Planet Aardvark

July 12, 2020

• The Wakes I Leave An Overnight in Crystal Bay, Swinging at the Anchor

  On July 8, a warning for violent storms was in the forecast for southern Ontario. However, by mid-afternoon, radar images to the NW seemed to make this forecast quite unlikely, and Sassy and Woodpecker agreed to make a late dash into Lac Deschênes. Prevailing surface winds were SW at less than 5 Kts. and the nearby Crystal Bay shore, west and not far from the marina, seemed ideal for anchoring on its lee to cool down from the heat wave that affected the area.

   Woodpecker undocked aroud 18:00, ahead of Sassy and waited for Sassy outside the KN channel. It was also a good opportunity for Sassy to try her new VHF marine radio. With the small Standard Horizon HX40 providing direct communication between both vessels, the boats sailed together heading NW. With water levels one foot above datum there were no concerns about touching bottom, least of all coming aground. Woodpecker chose an anchorage just west of Rocky point, and Sassy followed suit dropping anchor a couple of boat length east from her companion of adventure. Woodpecker’s crew immediately made to the water in their unique dinghy designs for an overboard chat on a wealth of topics. Then, as the Sun started approaching the horizon…

  

   …it was time for some tough decisions about the future: Sassy decided in favour of an overnight swinging at the anchor and she watched Woodpecker sail away into the initial shadows of the night with the city silhouette lighting up in the background. The anchor light started to shine at the tip of Sassy’s mast and, after a frugal dinner, mosquito nets were installed in all hatches and the cabin was prepared for the night. Sleep was interrupted around 1:00 AM to come on deck, check the boat and the surroundings, assess the position and watch the night sky. The waning gibbous moon was shining towards the SE, some 10 degrees above the horizon, with Saturn and Jupiter shining to the South in a horizontal line within Sagittarius, not far from the hidden center of the galaxy. Both dippers were magnificent high above with, Polaris, the Northern star, clearly visible.. East of it was the Summer triangle (Deneb, Altair and Vega) and not far from it the “W” of Casiopeia leading the entire cast of the mythical characters in the legend of Andromeda. By 5:00 AM birds started singing ashore and within a few minutes, Sassy was able to witness the return of the Sun, emerging red over the city’s silhouette towards the East:

  

  After a breakfast on deck of expresso coffee and toasted bagels and jam, the air started to quickly warm up and it was time to return to port with enough time to dock and snug the boat before the heat would become unbearable. Close to 8:00 AM on July 9, Sassy was again docked at her slip in the marina after having provided her skipper with another amazing night at the anchor, away for a while from all the mythologies that so often obscure in humans their perception of reality.

July 11, 2020

• Oshpark Olimex designing powerful Linux board with KiCad

  Gareth Halfacree writes on Hackster about Olimex’s new project:

  

  Olimex’s Tukhla, Built Around the i.MX8QuadMax, Targets Open-Hardware Linux Power Users

  Bulgarian open-hardware specialist Olimex has revealed details of what it describes as its “most complex OSHW board yet:” an NXP iMX8QuadMax-based single-board computer dubbed the Tukhla.

  “[A] company from EU which values the OSHW [Open Source Hardware] recognized the absence of high-end open source Linux board and asked us to design one,” Olimex’s Tsvetan Usunov explains. “They offered to cover all associated design costs. They specially requested this to be not yet another [Rockchip] RK3399 board, but based on SoC with proper documentation and software support. NXP’s high end iMX8QuadMax matched their requirements perfectly.”

  “Currently all powerful Cortex-A72 comes from Chinese or Korean origin and are always closed projects, the only published info in best case is PDF schematic which can’t be verified i.e. the final product may or may not match what they publish. The popular Raspberry Pi goes even further and their ‘schematics’ are just connector diagrams.”

  

  The Tukhla, by contrast, will be a fully open design, Usunov promises — built in the open source KiCad electronic design automation (EDA) package. Aside from the iMX8 SoC itself — which includes two Arm Cortex-A72 cores, four Cortex-A53 cores, two Cortex-M4F cores, and a quad-core graphics processor with 32 OpenGL ES 3.2 and Vulkan compatible compute units — the board will include up to 16GB of LPDDR4 memory, microSD support, eMMC and QSPI flash storage, a SATA connector, two single-lane PCI Express connectors with NVMe support, HDMI input and output, USB 2.0 OTG and USB 3.0 Host support, two gigabit Ethernet ports, and two MIPI CSI camera connectors.

  We started the most complex design of Open Source Hardware Linux Computer with iMX8QuadMax SOC, to be completed with KiCAD and here are the details: https://t.co/HsAQibtaNI #oshw #linux #arm #imx8 #automotive #industrial #kicad @NXP pic.twitter.com/0GTPZURujo

  — OLIMEX Ltd (@Olimex) July 7, 2020

• Astro Bob How To Share Comet NEOWISE With Your Kids

  

  Something as wonderful and rare as a bright comet should be shared with as many people as possible. I understand it’s not easy getting up at 3 a.m. and driving to a place with a view, but I’ve yet to hear from anyone who felt put out after they made the effort to see comet NEOWISE. I was eager to show my daughters so I asked them to join me for a look. One was unable due to work but the other agreed. She normally stays up all night anyway. I like to tell her she already has the key qualification to becoming an amateur astronomer.

  

  We rose this morning at 3 and set off to see the comet. Once out of the car she looked around the sky and bingo, she found it just like that.  It appeared as a ghostly streak of light with a bright, point-like head. With the naked eye alone I could trace the tail for 4.5°, equal to 9 full moons. In binoculars and photos it extended all the way to Theta Aurigae (see map below), a distance of 8°. While the head is fading the tail just grows and grows, making the comet a more impressive sight now than a week ago when it was officially brighter.

  How fortunate to see a bright comet. And how rare. The last gem was Comet PanSTARRS in 2013, but it was nowhere near as easy to see as NEOWISE. The most comparable recent comet was McNaught which turned up in the winter sky in 2006 en route to a fantastic appearance in the southern hemisphere in 2007.

  

  If you have kids, now is the time to take them out and show them the comet. You even have half a moon to help light your path. Tomorrow it will pass near the planet Mars, another point of wonder in the sky. Make it a special occasion with hot chocolate or iced tea depending on your climate. Kids rebound quickly after losing sleep plus they’re almost always up for an adventure. My daughters were.

  

  Expect surprises, too. Where we live the mosquitos are bad on warm nights. They’re understandably hungry like every other living thing. From their perspective we arrived just in time for breakfast. After their peskiness nearly derailed our little expedition we settled in for a walk along the adjacent road, watched NEOWISE fade in the brightening sky and found relief. We also met up with a man out on his bike in search of the comet. It was an opportunity to share our mutual enthusiasm for sky-watching.

  

  Use the maps provided to help you find comet NEOWISE. If you’re bringing young children ask them later to make a drawing of what they saw with crayons or colored pencils. What a nice keepsake that would make. Talk to them about comets. People used to be afraid comets were portents of disaster. Now that we know what they are — small asteroid-like objects but made of dirty ice instead of rock — we can appreciate them for their beauty. Every time a comet goes around the sun some of that ice vaporizes in our star’s terrible heat to form a tail that lights up like the dust that rises from a dusty road. And it’s currently shining from over 80 million miles (129 million km) away. What a big place the solar system is with room for one star, at least eight planets and billions of comets and asteroids!

  Many have asked when is the best time to see NEOWISE. From most locations look between 2¼ hours to 1 hour before sunrise. If I had to pick a sweet spot it would be 3:20 a.m. to 4 a.m. local time. Whether going by yourself or with the little ones don’t forget the bug repellant if you live in the humid, eastern half of the U.S. And If you need another reason to go out consider that the comet won’t return again for another 6,800 years! For this particular object, it’s definitely a “once-in-a-lifetime.”

• Loren Grush SpaceX delays launch of its latest batch of Starlink satellites, with two hitchhiking spacecraft
  

  Update July 11th, 9:30AM ET: SpaceX postponed the launch again on Saturday morning, “to allow more time for checkouts.” The company says it will announce a new launch day once it’s confirmed.

  Original Story: A little over a week after launching a GPS satellite for the Space Force, SpaceX is back with another launch of its internet-beaming Starlink satellites. The company’s Falcon 9 rocket is slated to take off from Cape Canaveral, Florida, launching 57 Starlink spacecraft as well as two hitchhiking Earth observation satellites from operator BlackSky.

  The flight is the latest in SpaceX’s ongoing quest to flesh out its proposed massive Starlink constellation, aimed at providing broadband internet connectivity from space. The company has...

  Continue reading…

• DragonflyBSD Blog In Other BSDs for 2020/07/11

  Dragged right out of my RSS feeds.

  •  Chai-Fi, the minimalistic wpa_supplicant.conf “manager” for FreeBSD.  (via)
  • Valuable News – 2020/06/29 and Valuable News – 2020/07/06.
  • Classic ThinkPad Thermal Paste Change.  Bookmarked cause I’ll eventually need it.  There’s a Lenovo fan control for BSD buried in there too.
  • FreeBSD Virtual Bug Squash event, happening today.
  • Deep Integration of Filesystem Extended Attribute Support.  (HardenedBSD)
  • OPNsense 20.1.8 released.
  • TrueCommand 1.3 out.
  • OpenBSD upgraders need to delete libperl.a.
  • Diablo (Hell/Hell co-op) – PlayOnBSD.  (via)
  • Emulex – Cheapest 10GE for Your Homelab on FreeBSD.  (via)
  • Tutorial sites treating FreeBSD like a Linux distro.
  • Via previous link: Everyone should buy the USEBSD sticker.

  Also on:

  Twitter

• Bruce Schneier Friday Squid Blogging: China Closing Its Squid Spawning Grounds

  China is prohibiting squid fishing in two areas -- both in international waters -- for two seasons, to give squid time to recover and reproduce.

  This is the first time China has voluntarily imposed a closed season on the high seas. Some experts regard it as an important step forward in China's management of distant-water fishing (DWF), and crucial for protecting the squid fishing industry. But others say the impact will be limited and that stronger oversight of fishing vessels is needed, or even a new fisheries management body specifically for squid.

  As usual, you can also use this squid post to talk about the security stories in the news that I haven't covered.

  Read my blog posting guidelines here.

• Exosky.net Jupiter and Callisto

  Jupiter’s moon Callisto was in the frame for this image from July 9. The seeing was quite good, despite the 28 degree altitude.

  

July 10, 2020

• Oshpark Dream Team Members Announced for the 2020 Hackaday Prize

  

  The Dream Team program is an exciting new element of the 2020 Hackaday Prize, with twelve people accepted to work full-time on a specific problem for each of our non-profit partners this summer. Each team of three is already deep into an engineering sprint to pull together a design, and to recognize their efforts, they’ll be receiving a $3,000 monthly microgrant during the two-month program.

  Join us after the break to meet the people that make up each of the teams and get a taste of what they’re working on. We’ll be following along as they publish detailed work logs on the Dream Team project pages.

  via Dream Team Members Announced for the 2020 Hackaday Prize
• Astro Bob Comet NEOWISE Grows Another Tail

  

  This comet just keeps on getting better. I was out again at 3:30 this morning and found Comet NEOWISE without even trying. Early on its head appears faint because of low altitude, but the tail is growing. I could easily see 3°-4°of it with the naked eye. Binoculars and photos doubled that. By 4 a.m., when the comet’s head was high enough to see clearly, it looked exactly like a star. I was also able to photograph the comet’s ion tail for the first time. Although I don’t know the length of this delicate appendage, the dust tail is at least 10 million miles (16 million km) long. Dust deposited in the orbit of the comet gives the tail a curved shape.

  

  Ultraviolet light from the sun strips electrons from the gases released from vaporizing comet ice turning them into ions. If an atom or molecule gains or loses electrons it’s no longer “neutral” but said to be ionized. Ionized gases are strongly affected by magnetic fields bundled in the solar wind, the steady “breeze” of minute, subatomic particles blowing from the sun. By the way, these are the same specks that spark auroras. Comet ions are directed by the solar wind into a tail directly behind the comet.

  

  As of July 10 NEOWISE is now magnitude 2, so it’s faded a little, but that’s been more than offset by the comet’s increasing altitude and the waning of the moon. If you have a telescope be sure to look at the comet for a powerful eyeful. Then, as dawn gets too bright to see NEOWISE well, swing your scope over to the waning moon for a look at some of the most incredible crater fields you’d ever want to see. After the moon, visit Mars. The moon passes to the lower right of the planet on July 11 and to the lower left on the 12th. Use high magnification and you’ll see the coolest feature Mars has to offer — its stunning south polar cap.

  

  Richard Mitchell, one of our readers, reminds us that Venus is also at maximum brilliancy, another reason to get out at dawn. Coincidentally, it’s crossing the Hyades star cluster in Taurus, making for a pretty binocular sight.

  

  I normally wake up around 8 in the morning but thanks to NEOWISE I’ve been rising around around 10 … with a ferocious appetite after being out all morning! Let the comet change your life a little. If nothing else it’ll take your mind off COVID-19 for a little while. Clear skies!

  

   

   

   

• Bruce Schneier EFF's 30th Anniversary Livestream

  It's the EFF's 30th birthday, and the organization is having a celebratory livestream today from 3:00 to 10:00 pm PDT.

  There are a lot of interesting discussions and things. I am having a fireside chat at 4:10 pm PDT to talk about the Crypto Wars and more.

  Stop by. And thank you for supporting EFF.

• Centauri Dreams What Can SETI Scholars Learn from the Covid-19 Pandemic?

  The pandemic has everyone’s attention, but it’s not too early to ask what lessons might be learned from public response to it. In particular, are there nuggets of insight here into what might occur with another sudden and startling event, the reception of a signal from another civilization? John Traphagan takes a look at the question in today’s essay. Dr. Traphagan is a social anthropologist and Professor of Religious Studies, in the Program in Human Dimensions of Organizations, and Mitsubishi Fellow at the University of Texas at Austin. He also holds a visiting professorship at Waseda University in Tokyo, as well as being a board member of SSoCIA, the Society for Social and Conceptual Issues in Astrobiology. His research focuses on the relationship between science and culture and falls into two streams: life in rural Japan and the culture and ethics of space exploration. John has published numerous scientific papers and several books, including Science, Culture, and the Search for Life on Other Worlds (Springer, 2016). His most recent book, Cosmopolitan Rurality, Depopulation, and Entrepreneurial Ecosystems in 21st Century Japan, was published in 2020 by Cambria Press. This essay is a shorter version of a more detailed paper that is slated to appear in JBIS.

  by John W. Traphagan

  

  For people interested in the potential outcome of contact with extraterrestrial life, whether intelligent or otherwise, the Covid-19 pandemic is a timely case-study that can help us think through some of the challenges first Contact with ETI or even simple life might present for humans, because it represents a potential existential threat to the entire population of our planet. And that threat has forced governments into actions with widespread social, political, and economic implications up to world-wide depression.

  Like the emergence of Covid-19, first contact, in particular, has the potential to set in motion political machinations on the part of nation-states as national security interests are identified. If resources or information associated with contact are considered important to control by governments (see our earlier article On SETI, International Law, and Realpolitik in Centauri Dreams), then unexpected events which threaten global political and economic stability, regardless of the risks associated with contact itself may unfold. Indeed, this has been one of the outcomes of the Covid-19 pandemic in which there was early concern about the potential impact of policy responses to the pandemic and the associated collapse in oil prices. This could easily have led to political instability in already unstable areas of the world such as parts of the Middle East.

  In general, successful human response to a pandemic (such as Covid-19) is based on a combination of credible action by governments, strong leadership from international organizations such as WHO, and responsible behavior by nation-states concerned with the well-being of their populations. The same factors apply to contact with extraterrestrial life. In the event of an encounter with life from another world, public safety and health (including mental health) depend on: 1) timely and credible actions by governments where contact is made; 2) clear direction and leadership from international organizations and the scientific community to coordinate a global response; and 3) responsible behavior on the part of governments naturally concerned with protecting parochial national interests.

  In the case of non-intelligent extraterrestrial life, such as microbial life, the parallels with the Coronavirus pandemic are obvious, but are still complicated by the fact that we do not know how introduction of an alien microorganism into Earth’s ecosystem would affect life on Earth. But contact with any form of extraterrestrial life presents risks that have the potential to place our species in a position similar to what we are currently facing with Covid-19, which represents a global threat necessitating a global response.

  So, what can we learn from the pandemic? There are at least four tactical points to take away from our current situation:

  1. Differential values play a significant role in how governments respond to the pandemic, despite the fact that Covid-19 represents a global threat to human life.

  2. Each nation-state is largely going it alone in assessing the level of threat and developing appropriate responses to the pandemic based on risk assessments.

  3. There has been limited cooperation and some governments have withdrawn from the international political environment or even tried to thwart international organizations such as WHO.

  4. Responses to government rules such as wearing masks in public have varied and in some cases been resisted.

  The key point to take away from the Covid-19 pandemic for those interested in the potential risks and influences of contact with ETI is that different responses and policies are products of cultural, ideological, and political variations among and within nations of the world. Factors such as population density and socio-economic status also play a significant role in how the virus has spread and how governments and individuals have responded. And structural patterns of social and political life—such as the presence of systemic racism in the US—clearly shape how different people are affected by the pandemic. There is no reason to think contact with ETI would be different.

  Culture matters. There are at least three strategic lessons we can draw from this observation:

  • The world is unlikely to react as one. Even if it is determined that ETI poses an existential threat to humanity a well-coordinated and unified response to either physical or remote contact with ETI is unlikely, unless significant changes in human political behavior occur.

  • Culture will drive state and sub-state response. Cultural variation evident in complex and conflicting value systems will influence nation-states and other groups as they interpret and respond to contact.

  • Diversity of perspective, a significant advantage in assessing options, can be a hindrance to unified action. Diverse cultural, political, and economic characteristics that humans display and experience have the potential not only to provide multiple options in responding to contact, but may work against a successful response.

  We should be concerned. In the face of potential existential threat, unified and coordinated action is central to successful results—thousands of years of experience with warfare have shown this clearly to be the case. Unless we prepare for the fact of diversity in human responses to contact, rather than being a source of strength and options when facing contact that diversity may work against a coordinated effort.

  It would help for the SETI scientific community to move away from the often tacit assumption that humans live and operate within a single, unified (or monolithic) civilization to a concept of both our world and potential other worlds that expects diversity in cultures, interpretations, and likely responses to a contact scenario. Recognition of the potential for contact to stimulate increased conflict and disagreement among human groups—again as is evident in the Coronavirus pandemic—rather than to unify humanity in response to a real or perceived global threat, would represent a good starting point for thinking about protocols for contact.

  

  

  
• NK4GL N4KGL Plans for the 11 July RaDAR Challenge
  N4KGLwill operate RaDAR Challenge from Opal Beach on Santa Rosa Island in Northwest Florida. The island is very narrow with the Gulf of Mexico on the Southside and Santa Rosa Sound on the Northside. We will use a vertically polarized antenna to take advantage of the saltwater effect. Since the IARU HF Championship Contest will be underway, we will check 17 meters first, then 40 or 20 meters.  We will use low power and be on foot. Doing RaDAR, we will make five contacts and move one kilometer to the next stop, and repeat for four hours. Our start time is around 1600 UTC.

  
  

  Opal Beach is part of the National Parks Gulf Islands National Seashore and Parks On The Air. K-0661. We will spot to https://pota.us/#/ You can also set up your HamAlert for N4KGL  We welcome all chasers and especially RaDAR to RaDAR contacts. If you are out doing RaDAR or chasing, let me know via lanekg@gmail.com. 

  
  

  

  
  

  
  

  RaDAR is Rapid Deployment Amateur Radio. The Challenge rules are at http://radarops.co.za/index.php/radar-rules/ Thanks to Eddie ZS6BNE for the RaDAR concept. Good luck, and stay safe! 

  
  

  Dennis WA6QKN and Greg N4KGL

  
  

  

  
  
• Loren Grush How to catch a glimpse of the comet NEOWISE dazzling the skies right now
  Comet C/2020 F3 NEOWISE Near Barcelona. | Photo by Albert Llop / NurPhoto via Getty Images

  For any early birds who have ventured outside in the US this week, you may have seen a tiny — yet spectacular — sight in the pre-dawn sky. A comet with a bright, opulent tail has been gracing the skies in the wee morning hours before sunrise, and it’s been giving photographers quite the show for the last week.

  The comet is known as Comet C/2020 F3 NEOWISE — or just NEOWISE for short. Scientists just discovered the rock on March 27th. It gets its name from the NASA mission that discovered it, also called NEOWISE, for Near-Earth Object Wide-field Infrared Survey Explorer. The mission consists of a spacecraft in orbit around Earth that’s tasked with cataloging as many asteroids near Earth as possible — especially any that might be...

  Continue reading…

• Bruce Schneier Business Email Compromise (BEC) Criminal Ring

  A criminal group called Cosmic Lynx seems to be based in Russia:

  Dubbed Cosmic Lynx, the group has carried out more than 200 BEC campaigns since July 2019, according to researchers from the email security firm Agari, particularly targeting senior executives at large organizations and corporations in 46 countries. Cosmic Lynx specializes in topical, tailored scams related to mergers and acquisitions; the group typically requests hundreds of thousands or even millions of dollars as part of its hustles.

  [...]

  For example, rather than use free accounts, Cosmic Lynx will register strategic domain names for each BEC campaign to create more convincing email accounts. And the group knows how to shield these domains so they're harder to trace to the true owner. Cosmic Lynx also has a strong understanding of the email authentication protocol DMARC and does reconnaissance to assess its targets' specific system DMARC policies to most effectively circumvent them.

  Cosmic Lynx also drafts unusually clean and credible-looking messages to deceive targets. The group will find a company that is about to complete an acquisition and contact one of its top executives posing as the CEO of the organization being bought. This phony CEO will then involve "external legal counsel" to facilitate the necessary payments. This is where Cosmic Lynx adds a second persona to give the process an air of legitimacy, typically impersonating a real lawyer from a well-regarded law firm in the United Kingdom. The fake lawyer will email the same executive that the "CEO" wrote to, often in a new email thread, and share logistics about completing the transaction. Unlike most BEC campaigns, in which the messages often have grammatical mistakes or awkward wording, Cosmic Lynx messages are almost always clean.

• The Atlantic: In Focus Photos of the Week: Chicken Offering, Virginia Creeper, Comet Neowise (35 photos)

  Ominous statues in Thailand, protests in Serbia and Greece, solar boats in the Netherlands, a crane collapse in London, Formula One racing in Austria, the empty streets of Pamplona, a zoo re-opening in Ecuador, a nuclear power plant in France, a wildfire in California, and much more.

  

  
• XKCD Hamster Ball 2
  
• DragonflyBSD Blog BSD Now 358: OpenBSD Kubernetes Clusters

  This week’s BSD Now has a word combo I didn’t expect for a title, plus a number of useful learning links.  This week’s highlight: more Yubikey BSD support.

  Also on:

  Twitter

• Exosky.net About last night…

  The clouds cleared a bit last night, and there was some pretty good seeing behind them. I spend quite a bit of time on Jupiter (more on that in another post, after I’ve gone through the data), but I managed a shot of Saturn with a number of its moons in the field of view, just as it was transiting at about 29 degrees altitude.

  Visible in the image below are Saturn and its moons Dione, Tethys, and Enceladus (it’s the faint smudge to the right of the planet, about halfway to the edge of the image). Mimas in the in image very close to the rings, but is too faint (mag. 13) to show up against the brightness of the rings.

  

• Basic Instructions How to Craft a Sales Pitch

  

  I never thought about it before, but talking to a friend about your plan to “ask someone out” is similar to talking about your plan to “call someone out.” The intent is the opposite—fighting vs. hopefully not fighting—but the sentence structure, the hushed tones of the conversation, and, sadly, the discomfort caused in the person you’re discussing can be very much the same.

  As always, thanks for using my Amazon Affiliate links (US, UK, Canada).

• Eli My YouTube channel

  https://www.youtube.com/channel/UCjaUawnq7elxGo0kyDdJpoQ?view_as=subscriber

• Eli how do you know how much you have been a lot to me back and then do it haha 😆 I was a good time to get you back to my sleep and I am gonna I am so glad I did that it was really good
  2030-07-09T17:02:55

    days

    hours  minutes  seconds

  until

  It stops raining

  Just kidding. It will never stop raining.

  Hello hello there. It’s Eli again but i don’t know what to talk about again. But I will think of something. Today is Thursday and I delivered newspapers today so yeah. I have some money to spend and I need suggestions for what to buy so comment what you think I should buy. Maybe I will buy a car so I can go go go somewhere.
  I have a YouTube channel if you didn’t know that and I will put the link to it later on in this post. By the way if you could share this with somebody that would really help out a lot so yeah . I am very bored because it rained today and I didn’t do anything except deliver newspapers and write in this. Help help help help so bored . If you can’t read this, try harder. Seriously. It looks like I haven’t written a lot, but I actually have. So here is the end now. Bye bye

  Hey look it’s a meatball

  

• Hillel Wayne (Software Engineering: Oxymoron or no?) The Frink is Good, the Unit is Evil

  

  One day Alan Eliasen read a fart joke and got so mad he invented a programming language. 20 years later Frink is one of the best special purpose languages for dealing with units.

  “But why do we need a language just for dealing with units?” Glad you asked!

  Intro to Units

  A unit is the physical property a number represents, like distance or time. We almost always are talking about SI units, or Système international. That’s things like meters, seconds, kilograms, along with prefixes like kilo- and mega-. One kilometer = 1000 meters, 1 centimeter = 1/100th of a meter.

  Units can have exponents: m² is square meters, m³ is cubic meters, m * s^-1 is speed. These form new physical properties, or dimensions. We can multiply and divide numbers with different dimensions but not add them. I can add 1 m + 1 m, but not 1 m + 1 kg. A unit-aware language needs to be able to track units and make sure that I don’t add incompatible dimensions. It also should also make sure that I pass correct units into functions that depend on units. A pressure calculation would take an area and a force, not a frequency and an amperage.

  Simple, right?

  Nope

  First of all, there are multiple different representations of units. There’s the SI system, which all sane, right-thinking nations use, and then there’s the American system.¹ Feet and meters are both distance. Is it okay to mix feet and meters? This is the bug that destroyed the Mars Climate Orbiter. But there are also valid uses cases where you’d want to mix them! When I cook, I use a mix of metric weights and American volumes, like 1 cup of water and 128 grams of flour. In the UK, beer is measured using pints but its alcohol by volume is measured in SI.

  Different dimensions doesn’t always mean the units are incompatible. There’s a nonstandard set of units called “Gaussian units” used in some niches of physics. In SI, capacitance is measured in Farads, which has dimensions A² s⁴ kg^-1 m^−2. In Gaussian units, capacitance is measured in cm. If you’re explicit about what you’re doing you can add these seemingly-incompatible dimensions.

  Dimensions aren’t unique, and two incompatible physical quantities can have the same dimension. The canonical example is that energy and angular force are both measured in Newton-meters.² There are also plenty of domain specific examples. As you enter a gravity well, the rate at which gravitational force changes has dimensions N/m. Surface tension is also measured in N/m.

  What else?

  • What’s 200° + 360°? It could be 200° or 560°, depending on we have a “circular angle” or a “rotational angle” (like driving a screw in).
  • Some quantities are unitless. What’s 20° + 1 radian? They’re both unitless quantities that have compatible dimensions. What about adding two ratios? What about adding a radian to a ratio?
  • Units can have additional limitations. You can subtract timestamps from each other but not add them.
  • Units can have different historical values. A foot is defined as exactly 0.3048 meters. Before 1959, though, it was 0.3048006 meters. This is means that all historical documents have a different measurement of foot. And there was a period of time where we used both definitions in different places!
  • Uncertainties. If you’re working with physical measurements, all of your measurements will have some amount of uncertainty. What happens when you add two meters, plus or minus a centimeter?

  If you want to learn more about how evil units are, check out Bill Kent’s Measurement Data Report.

  Some solutions

  Adding units of measure to a language is tricky. It’s not just that there are many hard domain problems, there’s also different tradeoffs in solutions. Do we want compile-time or runtime correctness? Should units be part of the type system or is there a better representation? How do we handle derived units? How do we handle generics? A good overview of the design challenges is here, which discusses some of the solutions proposed for Ada.

  This page covers how various languages approach measurements. For the most part, they punt the question to preprocessors and libraries, limiting how much they can help you. The only mainstream language with built-in support for units of measure is F#. F# focuses on catching all errors at compile time. All conversions between units must be made explicit, so you can’t accidentally add feet and meters. The price for this is flexibility: you can’t add centimeters and meters, either.

  // Mass, grams.
  [<Measure>] type g
  // Mass, kilograms.
  [<Measure>] type kg
  
  // Define conversion constants.
  let gramsPerKilogram : float<g kg^-1> = 1000.0<g/kg>
  
  // Define conversion functions.
  let convertGramsToKilograms (x : float<g>) = x / gramsPerKilogram
  

  That’s a good design choice for F#’s goals. It adds boilerplate but keeps your software from going haywire. This is appropriate for industrial software where a lot of people could be affected by a bug.

  It’s less appropriate for low-stakes, small scale work. Boilerplate makes it harder to use things interactively. If I’m trying to find the Titanic’s weight in cups of rice I don’t want to spend ten minutes writing unit conversions. For that, the most common tool is units, a GNU program for conversions:

  You have: 12 ft + 3 in + 3|8 in
  You want: ft
          * 12.28125
          / 0.081424936
  

  units is a fine piece of software, but it’s not a programming language. I want a language that has built-in dimensional analysis but doesn’t need a lot of boilerplate. Something more powerful than units but not as strict as F#.

  Frink

  That’s where Frink comes in. In Frink, any number can be tagged with a unit. Frink will prevent you from adding incompatible units, same as F#.

  > 1 meter
  1 m (length)
  
  > 1 meter + 2 kilograms
  Error when adding:  meter + 2 kilograms
   Cause: Conformance Exception:
   Cannot add units with different dimensions.
    Dimension types:
     m (length)
     kg (mass)
  

  The syntax is designed to look like “natural” math, so a space counts as a multiplication. 1 meter is actually 1 * meter. This may seem like it’ll cause some problems, but it’s actually kinda nice. It makes translating equations to Frink easier.

  By using the -> operator, we can convert a value between two units. We can choose whether we include the name of unit in the conversion or not by putting it in quotes.

  > 10 meters + 2 furlongs -> "feet"
  2029212500/1499997 (approx. 1352.8110389554112) feet
  

  Frink comes with a boatload of predefined units; it’s default units file is over 5,000 lines long.

  //How do you measure, oh measure a year?
  > 525600 minutes -> years
  0.99933688171353600106
  
  > 525600 minutes -> siderealyears
  0.9992981356527034257
  
  > 525600 minutes -> gaussianyears
  0.99926355644744010579
  
  > 525600 minutes -> calendaryear
  1
  

  You can also define new units at runtime in terms of other units.

  > corn_on_sale := 0.25 USD
  // If we had a living wage, how many ears/corn 
  // could you buy with one days labor?
  > 15 USD/hour * 8 hours -> "corn_on_sale"
  480. corn_on_sale
  
  > 15 USD/hour -> "corn_on_sale/(8 hours)"
  480.0 corn_on_sale/(8 hours)
  

  Prefixes in Frink are just multipliers. I can write kilofeet and it automatically knows that means “1000 feet”. Frink also knows common terms like half and square.

  > square megapaces
  5.80644e+11 m^2 (area)
  

  You can break down conversions into multiple units.

  > 1 kilometer -> ["kilofeet", "feet", "inches"] 
  3 kilofeet, 280 feet, 1280/127 (approx. 10.078740157480315) inches
  
  > 1 kilometer -> ["kilofeet", "feet", "inches", 0]
  3 kilofeet, 280 feet, 10 inches
  

  Frink functions work as you’d expect, but you force parameters to conform to dimensions and preconditions.

  > sphereVolume[radius is length] := 4/3 pi radius^3 
  
  > sphereVolume[2]
  Error when calling function sphereVolume:
    Constraint not met--value must have dimensions of length
  

  Functions can also be the target of a conversion.

  > HMS[1 day]
  24 hours, 0 min, 0 sec
  
  > (10 miles) / (3 mph) -> HMS
  3 hours, 20 min, 0 sec
  

  Affordances

  Frink really shines in its affordances. It needs to be pleasant and reasonable if people are going to use it interactively. Frink does lots of small things to help with this. Some examples:

  You can change the display units for a dimension.

  > length :-> [feet, inches, 0]
  
  // All lengths are now in feet and inches
  > 1 meter
  3, 3
  
  // areas are unaffected
  > 2 m * 2 m
  4 m^2 (area)
  

  You can globally set precisions and output formats.

  > setPrecision[6]
   
  > setEngineering[true]
  
  140.5 million meters
  140.500e+6 m (length)
  

  You define entirely new dimensions and prefixes.

  > population =!= person
  > 2.7 megaperson / (5 square miles) -> (square feet) / person
   Warning: reciprocal conversion
  51.626666666666666665
  

  By using ?str you can get a list of all the existing units which start with str. By using ?? it also gives you the value of the unit.

  > ?foot
  [acrefoot, arabicfoot, assyrianfoot, boardfoot, cordfoot, doricfoot, earlyromanfoot, foot, footballfield, footcandle, footlambert, frenchfoot, greekfoot, ionicfoot, irishfoot, lateromanfoot, northernfoot, olympicfoot, romanfoot, scotsfoot, sumerianfoot, timberfoot]
  
  > ??foot
  arabicfoot = 0.270256 m (length)
  assyrianfoot = 0.27432 m (length)
  boardfoot = 18435447/7812500000 (exactly 0.002359737216) m^3 (volume)
  \\ it goes for a while
  

  There’s special syntax for representing timestamps, which makes it easy to convert dates and times.

  // Meeting is tomorrow, 3 PM Paris time, what's that in New York?
  > # 3 PM Paris # + 1 day-> "New York"
  AD 2020-07-10 AM 09:00:00.000 (Fri) Eastern Daylight Time
  

  Some Use Cases

  Eliasen loves cooking, so Frink has a lot of food measurements. A lot of baking recipes call for a volume of “sifted flour”, but sifting is messy, annoying, and imprecise. We should measure them by mass instead:

  > ?flour
  [breadflour_scooped, breadflour_sifted, breadflour_spooned, 
  cakeflour_scooped, cakeflour_sifted, cakeflour_spooned, 
  flour_scooped, flour_sifted, flour_spooned]
  
  > 2.5 cups flour_sifted -> grams
  283.49523125
  

  Let’s do something more complicated. Like Eliasen, I also love cooking. While I mostly make savory dishes, I also specialize in chocolatiering. I’ve always been a little curious about how many calories each of my chocolates are, so let’s try to figure that out using Frink.

  

  For this example I’ll use the Chai tea recipe from the CIA book.³ Here’s the list of ingredients:

  Ingredient	amount (g)	serving size	Calories[^kcal]
  Heavy Cream	180	1 tablespoon	50
  Milk Chocolate	460	1.55 oz	235
  Corn Syrup	60	2 tbsp	120
  Tea Blend	10 g	-	-
  Butter	20 g	14 grams	100

  I pulled the calories of each ingredient from its label, with the exception of the milk chocolate, as I buy that in bulk. Instead I found information online here. Not the same kind of milk chocolate, but it’ll do for an estimate.

  > specific_energy :-> "kcal/gram"
  > energy :-> "kcal"
  

  The :-> changes the default unit representation. Without it specific energy would be presented in base SI units, which would be joules per kilogram. Next I put all of the measurements into dictionaries. I didn’t bother converting every measurement to SI units, as Frink can calculate the ratios for me.

  kcg = new dict // kcal/gram
  kcg@"hc" = 50 kcal / (tablespoon heavycream)
  kcg@"cs" = 120 kcal / (2 tablespoon cornsyrup)
  kcg@"butter" = 100 kcal / (14 grams)
  kcg@"mc" = 235 kcal / (1.55 oz)
  
  recipe = new dict //what actually goes in
  recipe@"hc" = 180 grams
  recipe@"cs" = 60 grams
  recipe@"mc" = 460 grams
  recipe@"butter" = 20 grams
  
  ing = ["hc", "cs", "mc", "butter"]
  
  total_cals = 0 kcal
  for x = ing
    total_cals = total_cals + recipe@x kcg@x
  

  Depending on the shell, this is enough for somewhere between 80 and 100 chocolates. We can model this uncertainty with an interval:

  made = new interval[100, 120]
  

  Instead of having an exact number, we have an upper and lower bound on the number. All math done with the interval instead change the bounds. ⁴

  > x = new interval[80, 100]
  [80, 100]
  
  // frink does interval math
  > x + 2
  [82, 102]
  
  > x * 2
  [160, 200]
  
  > x - new interval[80, 100]
  [-20, 20]
  
  

  But there’s more to a chocolate than its filling. There’s also the shell around it, which is going to have a different specific energy than the filling. To figure out how much shell there is per chocolate, I weighed 10 chocolates and took the average. That gave me 9 grams per chocolate. I know roughly how much of the filling there is per chocolate, based on how many chocolates I made from the filling. Subtracting the mass of the filling from the mass of the chocolate gives me the mass of the shell.

  dictsum[d] := sum[map[{|x| x@1}, d]]
  
  // grams per chocolate
  gpc = new dict
  gpc@"recipe" = dictsum[recipe] / made
  gpc@"dc" = 9 grams - gpc@"recipe"
  

  From then is a straightforward calculation to figure out how much calories both the shell and the filling have in total. And that gives me the total calories of the chocolate.

  println[(total_cals / made)  + kcg@"mc" * gpc@"dc"] 
  

  This tells me that each chocolate is 40-50 kcal, which is about what I expected.

  ---

  If you’re interested in Frink, you can download it here. At the very least I’d recommend checking out the default units file; it’s a hilarious and insightful introduction to just how weird units can be. I’ll leave you with some of his comments on candela:

  I think the candela is a scam, and I am completely opposed to it. Some good-for-nothing lighting “engineers” or psychologists probably got this perceptually-rigged abomination into the whole otherwise scientific endeavor.

  What an unbelievably useless and stupid unit. Is light at 540.00000001 x 10^12 Hz (or any other frequency) zero candela? Is this expected to be an impulse function at this frequency? Oh, wait, the Heisenberg Uncertainty Principle makes this impossible. No mention for correction (ideally along the blackbody curve) for other wavelengths? Damn you, 16th CGPM! Damn you all to hell!

  Thanks to Jubilee Young for making the opening image. Composite images are from Sean Connery in Zardoz and Alan Eliasen’s homepage.

  ---

  1. Blame Ronald Reagan. We were supposed to have completed metricization by the 90’s, then Reagan killed the program. ^[return]
  2. They aren’t exactly identical dimensions, as energy is a scalar and torque is a vector. But the vector components of torque have the same dimensions and are scalars. ^[return]
  3. The other CIA. ^[return]
  4. Frink treats intervals as a single unknown value inside the interval, not the range itself. This means that for any interval x, x - x = 0. ^[return]

July 09, 2020

• Loren Grush NASA is updating its guidelines on how to prevent contamination of the Solar System
  An artistic rendering of astronauts landing on the surface of the Moon again | Image: NASA

  After years of debate, NASA plans to update its guidelines for how much biological contamination of other worlds will be allowed while the agency explores the Solar System. The new rules would relax some of the agency’s requirements for how to explore the Moon and Mars — two high-profile destinations where NASA hopes to send astronauts in the coming years.

  For decades, NASA has followed fairly strict rules about how much biological contamination is considered acceptable whenever the agency sends probes — or people — to other planets. It’s a concept known as planetary protection, and it has a legal basis in a treaty signed more than 50 years ago. Called the Outer Space Treaty, it challenges nations to explore other worlds “so as to avoid...

  Continue reading…

• Jetson Hacks JetPack 4.4 Over The Air (OTA) Update issues

  Over The Air (OTA) updates is one of the new features for the JetPack 4.4 Production Release – L4T 32.4.2. Unfortunately, there are some issues with this feature that people are encountering in the product rollout.

  Here’s the money quote from NVIDIA:

  Note: We have temporarily disabled the feature of upgrading JetPack or L4T using debian package management tool due to an issue we found in one of our debian packages causing the device to not boot properly. We have identified the root cause and fixing it currently. We will re-enable this feature soon once fixed and update this post.

  Please note that one can still install JetPack using SDKM or downloading SD card images (for Jetson Nano and Jetson Xavier NX) from the JetPack page.

  The major issue people are reporting is that after a system upgrade, the Jetson boots, but goes to a blank screen with a blinking cursor. You can read through this thread on the Jetson Xavier NX forum: Jetson Xavier NX not booting.

  There appears to be a work around, but since these issues are just coming to light the day of the rollout it feels prudent to take this into account before upgrading your system.

  Note: If you create a system from a JetPack 4.4 SD card image (on the Jetson Nano and Jetson Xavier NX) or install JetPack 4.4 using the SDK Manager (Jetson AGX Xavier, Jetson TX2), you will not encounter these issues. However, if you issue the commands:

  $ sudo apt update
  $ sudo apt upgrade

  When you reboot the system, you will get a black screen and a flashing cursor, no GUI.

  OTA updates is one of the most anticipated features of this release. The folks at NVIDIA are working on this, there should be fixes soon.

  The more you know …

  The post JetPack 4.4 Over The Air (OTA) Update issues appeared first on JetsonHacks.

• Astro Bob Comet NEOWISE Hits It Out Of The Park!

  

  With no baseball season yet underway we’ll have to depend on Comet NEOWISE for home runs for the time being. I hope you’ve had the opportunity to this delicate spectacle. If you’ve been unable to do so because of schedule or weather, hang in there. The comet will be around for a while. Although it’s slowly fading (now around magnitude 1.5-2) it’s still very obvious in binoculars and faintly visible with the naked eye even from suburbs and some cities.

  Here’s a report I received today from Jim Twellman, one of our readers:

  “I’m in Lake St Louis, a suburb 30-some miles west of St Louis. I viewed the comet the last 3 mornings. Today the sky was nearly crystal-clear, and I viewed the comet naked eye before ever getting the binoculars out. No need to use the binos to hunt for it. I was able to see it naked eye here from about 4:22 to about 4:55 AM, but those last 5 minutes it was diminishing rapidly.”

  

  I last saw the comet on July 8 before it was overtaken by clouds. Its visible tail had doubled in length (to 6°) from the previous morning, and it was a little brighter to the naked eye, too. Telescope and binoculars gave the best views. Because the sun is rising a little later and the moon is waning, dawn views of the comet and its long tail should improve a little in the coming days even as NEOWISE commences to fade.

  I did a careful check and it will be possible to see NEOWISE at dawn through July 18. At the same time, you can watch for it in the evening twilight starting about July 12 when it will appear in the constellation Lynx the lynx which neighbors Ursa Major. From July 12-18 you can see it at both dawn and dusk.

  

  Once it pushes into the evening hours it will climb the northwestern sky and be more convenient to view, but it will be fading, too. I always recommend seeing transient phenomena like comets when they’re brightest and at the earliest opportunity if for other reason than the weather. You never know when you’ll be slammed by storms and like and for how long.

  

  NEOWISE is amazingly colorful, an aspect I tried to capture in the sketch and displays a wonderful, bifurcated (split in two) dust tail. Dust is released when comet ice vaporizes in the heat of the sun. Sunlight exerts pressure on the dust, blowing it back behind the icy comet to form a tail. We see tails because the particles are excellent at scattering sunlight just like dust or smoke does on Earth.

  

  Recently, the comet developed a second tail called the gas or ion tail. It’s faint, pale blue and very narrow. Few have seen it yet, but it does show in deep exposure photographs like the one above. Sometimes bright comets develop a very faint sodium tail made from glowing sodium atoms. No one has seen that yet assuming there is one.

  

  

  I’ve included a new map for you so you can see where the comet is headed as it moves into the evening sky. If you do spot this beauty please send me a report in the comments area or friend me on Facebook and comment there. Clear skies!

• Avazea (Philly-based data science corp) Introducing Raster Vision 0.12

  We refactored the Raster Vision codebase from the ground up to make it simpler, more consistent, and more flexible. Check out Raster Vision 0.12.

  The post Introducing Raster Vision 0.12 appeared first on Azavea.

• Centauri Dreams Spin-Orbit Alignment: A Lesson from Beta Pictoris?

  I hadn’t planned to write about the recent work out of the University of Exeter on Beta Pictoris, but yesterday’s article on KELT-9b dealt with planetary alignment, given that the planet shows marked spin-orbit misalignment. At Beta Pictoris, an international team of researchers led by Exeter’s Stefan Kraus has carried out measurements of the spin-orbit alignment of Beta Pictoris b, a gas giant orbiting a young star in an orbit about as distant as Saturn from the Sun. Here we have the first spin-orbit alignment measurement of a directly imaged planetary system.

  How such alignments occur is clearly relevant to planet formation theories. There’s a bit of astronomy history here, for spin-orbit issues became significant for both Immanuel Kant (1724-1804) and Pierre-Simon Laplace (1749-1827), who looked at spin-orbit alignment in our own Solar System. It was apparent to both that the planets known to them orbited the Sun not only in alignment with each other but in alignment with the Sun’s axis as well. Hence the idea that the entire system formed from a rotating planetary disc, and a flattened one at that.

  Other planetary systems may follow different paths of development, as Kraus notes:

  “It was a major surprise when it was found that more than a third of all close-in exoplanets orbit their host star on orbits that are misaligned with respect to the stellar equator. A few exoplanets were even found to orbit in the opposite direction than the rotation direction of the star. These observations challenge the perception of planet formation as a neat and well-ordered process taking place in a geometrically thin and co-planar disc.”

  Which is to say that close-in exoplanets can depart markedly from the apparent norm, making the study of these hot Jupiters significant for initial formation scenarios. Kraus and company went to work with the GRAVITY instrument at the Very Large Telescope Interferometer (VLTI) in Chile, exploiting the fact that a star’s spectral lines show a spatial displacement — an exceedingly small one, to be sure — caused by gas absorption in the star’s atmosphere. The team used this effect to determine the orientation of the star’s rotation axis.

  

  Image: The new observations show that the stellar equator (right) is aligned with the orbital plane of the planet Beta Pictoris b (middle) and the plane of the extended disc of debris material that surrounds the system (left). Credit: ESO/A.M. Lagrange; ESO/A.M. Lagrange/SPHERE consortium.

  At Beta Pictoris, some 63 light years from Earth, a displacement about 1/100th the apparent diameter of the star itself is used to demonstrate that planet and star are as well-aligned as our own Solar System. Thus the classic model of planet formation seems to apply, with implications for the hot Jupiters we see that demonstrate marked spin-orbit misalignment. From the paper (internal references removed for brevity):

  Our finding of spin-orbit alignment for β Pic b suggests that this planet formed in a coplanar disks without primordial misalignments. This is in contrast to theories that describe the occurence of obliquities as a natural by-product of the star formation process, for instance through turbulent motions in the star-forming cloud and fluid-dynamical effects during disk formation. In case our finding of a well-aligned system is representative for wide-separation planets, it would suggest that the population of Hot Jupiters on oblique orbits (found in RM survey at orbit separations between ∼ 0.02 and 0.3 au) are likely transferred to oblique orbits through dynamical processes post-formation. Possible mechanisms include planet-planet scattering, stellar flybys, or the Kozai-Lidov mechanism, where a wide companion orbiting a close binary on a highly inclined orbit can induce oscillations in inclination/eccentricity of the close pair.

  

  Image: To derive the stellar rotation axis of Beta Pictoris the team used the unique high angular and high spectral resolution mode of VLTI/GRAVITY to measure shifts in the centroid position in the hydrogen Brackett-gamma absorption line on micro-arcsecond scales. In the blue-shifted part of the absorption line, the centroid of the emission is displaced to the North-East, which indicates that the South-Western hemisphere of the star is approaching the observer. Credit: Kraus et al. / University of Exeter.

  Much depends on just how representative Beta Pictoris b really is of gas giants with wide separation from their star. The authors propose a new high-spectral resolution interferometric instrument at the VLTI to measure the spin-orbit alignment of hundreds of gas giants, dramatically increasing the data on long-period planets. Kraus is involved in a proposed VLTI
  visitor instrument called BIFROST that could enable such an observing campaign. This, in turn, should stoke the discussion of planet formation and system evolution when it comes to architectures as extreme as the one we see at KELT-9.

  The paper is Kraus et al., “Spin-Orbit Alignment of the β Pictoris Planetary System,” Astrophysical Journal Letters, Vol. 897, No. 1 (29 June 2020). Abstract / Preprint.

  

  

  
• Quanta Magazine The Scientist Leading the World’s Aurora Hunters

  The shimmering sheets of spectral light we call auroras were once attributed to many preternatural acts or supernatural entities: a glowing bridge that led deceased warriors to their final resting place, or the whipping of the tail of a fire fox as it zipped across the snow. Today, we know that the northern and southern lights are a manifestation of space weather — the complex entanglement, destruction and reassembly of Earth’s magnetic tendrils as the sun’s charged particles rain down onto the planet’s atmospheric shell.

  Like much that flickers in the night sky, auroras are as likely to inspire primal feelings of awe today as they were centuries ago. But serendipity plays an outsize role in the spotting of ephemeral auroras. That’s why Liz MacDonald — a space weather scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland, and the de facto ringleader of the world’s aurora hunters — decided to cheat.

  In 2011, a vibrant crimson aurora ignited the night skies in North America, stretching as far south as Alabama. Twitter — still in its relative infancy back then — lit up too, as people from across the continent shared their gleeful detections of it, often accompanied by their attempts at astrophotography. MacDonald was struck by the possibility of harnessing social media to crowdsource auroral observations.

  She went on to found Aurorasaurus, a free citizen science platform that tracks the appearance of auroras in real time. Whenever someone sees an aurora, they log on to the website, sign into the app, or tweet about it, and a marker appears on a map of the world adorned with the time and location of their sighting. What was a kernel of an idea nine years ago has exploded into an international platform with thousands of aurora hunters keeping their eyes trained on incandescent skies.

  Aurorasaurus doesn’t just vastly improve the odds of anyone out in the wilderness being able to locate these famous elusive displays themselves. Scientists also plunge into this ocean of data to improve their auroral forecast models, gaining a better understanding of the enigmatic electrified upper layers of the planet’s atmosphere as they do so.

  Case in point: In 2018, researchers described a new auroral phenomenon that was discovered with the help of the platform. Aurora hunters had noticed an elongated purple arc, sometimes accompanied by what looked like a green picket fence, lingering at surprisingly low latitudes in the night skies over Alberta, Canada. They named it Steve, a reference to an animated comedy film in which woodland critters give that moniker to a shrub simply because they have no other word for it. MacDonald enjoyed the name so much that she turned it into the backronym STEVE, for Strong Thermal Emission Velocity Enhancement.

  Quanta Magazine caught up with MacDonald over the phone, just as the coronavirus pandemic forced billions of people to hunker down in their own homes. The interview has been condensed and edited for clarity.

  How does it feel knowing that Aurorasaurus has grown into this enormous endeavor?

  It’s totally unexpected. For a while, it was an idea that wouldn’t let go, you know? But we all know that scientists are fairly slow at doing things, and you’re definitely swimming upstream to do something like this. But the idea just wouldn’t go away. I had really no idea how big of a thing it could be.

  We got a million-dollar grant — that was great — in 2013 to actually build the site. But it wasn’t fully recognized within my own community. I remember my first invited talk to speak about the topic — which I think wasn’t until 2015 or so. When I said, “We use data from Twitter,” the audience of space scientists laughed. And it surprised me, you know, that it was that funny. It is funny, but it also tells you something about how other people are not getting it. You definitely can’t convince everyone, but I think I’ve learned to believe in myself and in this less traditional work, and believe in it being very viable, both for the science and for the impact on people’s lives in all kinds of different ways.

  After having scientists giggle at your data source, what was it like to use that source to discover STEVE?

  It’s been really cool to be part of that discovery. The arcs themselves are not the discovery; the fact that we now understand part of the underlying phenomena is.

  Actually, we just came out with a new paper working with an aurora historian named Michael Hunnekuhl in Germany, who went on a search through all kinds of modern and historical archives of auroras. He found many past observations dating back hundreds of years, including observations by the famous Norwegian scientist Carl Størmer. Størmer took photographs of the aurora for 40 years, 100 years ago, and he observed STEVE on, like, seven dates. He described them as “feeble homogenous arcs of great altitude,” which is a pretty cool description.

  There’s been a lot of discussion about STEVE. Some people think it’s an aurora, some people don’t. A 2019 paper suggested it’s a hybrid, with the purple bit being a “sky glow” instead. Is a sky glow an aurora by another name?

  Sky glow is a term that’s already in use in the light pollution community, so that’s not my favorite term. I think we all agree that it’s not a typical aurora, caused by particles raining down on the atmosphere and transferring the energy as they go lower down the chute. In STEVE’s case, you have this crazy east-west flow, and that is somehow exciting neutral particles and causing light to be emitted.

  So it’s very different, but I still think it behooves us to call it an aurora. There are many atypical kinds of auroras. There’s something called black aurora: It’s invisible, but it’s still particles that you can’t see doing plasma-physics kinds of things.

  What we call is continuing to evolve. An aurora is many different things to many different people, to scientists and different cultures around the world.

  When new papers on STEVE are published, do you think people should focus less on whether it’s an aurora or sky glow, and instead underscore the science behind it?

  People can do whatever they want, including scientists. We all have the right to have our say on this.

  The press is geared to encourage the drama, though.

  Yeah. And you know, it’s interesting to learn what’s viral, the aspects of the drama and how that intersects with papers. It’s kind of crazy.

  Are there any aspects of the auroras that you’d want more of the public to understand — something really basic, a misconception about them, perhaps?

  There are a lot of misconceptions, which is more the fault of my side, the scientists’ side. But the main one is that it’s not the particles from the sun that are directly causing most of the auroras. Particles from the sun enter the Earth’s magnetic field region, and a whole bunch of complicated stuff happens in there, and those particles are eventually trapped on the magnetic field lines of the Earth and are transported away to the night side of the Earth. The aurora is the result of a continuous process of that energy coming into the Earth’s magnetic field, being stored, and then being released back to Earth.

  But all that is especially hard to explain using 2D pictures.

  Do you have a favorite spot to go see the auroras?

  Yeah! I am not technically allowed to endorse a place. But I recently got to go to a remote lodge outside Yellowknife in Canada, and I also got to go to Fairbanks, Alaska. I’ve seen the aurora in many different places, but it’s constantly varying, and it’s always super cool to see. For me, the experience of going to this lodge where you can just walk outside at night and see the aurora from anywhere on the property — including the hot tub — was really amazing. And you know, you have to have a bit of luck involved, but even though it’s the solar minimum right now — the sun is not that active — when you go that far north, if it’s not snowing the whole time, the everyday aurora, and this constant energy storage and release that happens every three or four hours, can be spectacular.

  Under the pandemic, can you still go to these remote places and still abide by social distancing rules?

  No, that lodge had to close. You can’t have tours come in, and they’re off-grid, they have no medical facilities, that sort of thing. You have to take a seaplane to get there. We got really, really lucky in our timing. And I’ve been very fortunate this past year to see auroras in Norway in September, when I got to go to Svalbard as part of the Hearts in the Ice expedition.

  They are closer to the aurora — which is 10 times higher than the clouds — than to the nearest town. And they are locked in the ice. They are remarkable, badass women. And their expedition is quite remarkable: They’re educating people, Skyping into classrooms, doing all kinds of citizen science projects, and raising awareness of climate change.

  While we’re all riding out the pandemic, are memories of past aurora viewings and thoughts of future expeditions keeping you sane?

  I’m doing science here at my house. It’s not aurora-related, but that is keeping me sane. And with citizen science, you can vicariously experience other environments. People who are in Alaska and Canada and other places — the aurora is still happening there. And people are still contributing. You can follow along and see some of their beautiful photographs and observations.

  Does the thrill of Aurorasaurus largely come from the idea of making scientific discoveries, or just getting more people to look up at the auroras in wonder?

  The beauty is that these data are scientifically useful and that we can then help people be more successful at seeing the northern lights. There’s also the fact that we’re leveraging and communicating with people that are already experts in these phenomena. We’re getting help from them, and then it’s a question of how we can give back.

  But also, for me, it’s been a way to reconnect with beauty. Some of that beauty, when you actually study the auroras and the data and all of that stuff, it can kind of get beaten out of you. So that’s where I’m coming from.

• Andrew LePage The Soviet Space Exhibit at the Boston Museum of Science – July 1990

  When I was growing up in the 1970s, I was already an avid space enthusiast who tried to keep abreast of all the latest space missions. While there was plenty of information to be had about NASA’s various programs through the news media and especially literature and pictures I got directly from NASA, the Soviet space program was largely a mystery to me. I had the occasional news item which would appear in the newspapers or news magazine to rely on as well as brief mentions in my various space books and more detailed articles which appeared from time to time in Sky & Telescope, Science News and other magazines I read. But aside from these brief glimpses, details on the Soviet space program were hard to find.

  For me, that all began to change once I entered college in the fall of 1980. I quickly discovered the weekly periodical Aviation Week & Space Technology which was one of the best places at the time to find news on the Soviet space program as well as detailed analyses. Other periodicals and my classmates’ interest in spaceflight further fueled my growing passion for the Soviet space program especially their crewed, lunar and planetary missions. I eventually special-ordered books on the subject by Nicholas Johnson, James Oberg and others which helped to fill in lots of details and identified many of the remaining mysteries.

  

  Here I am, a 19 year-old college student, sitting in front of an H-1 engine during my first visit to Kennedy Space Center in July 1981. (A.J. LePage)

  After I graduated college with my degree in physics, I continued digging into the Soviet space program in my free time learning all that I could. By the late 1980s, I joined an informal study group of like-minded Soviet space enthusiasts in the Boston area called Krasnaya Orbita (“Red Orbit”, in Russian) where we shared information and the results of our analyses projects. With the start of Glasnost in 1986, even more information about the Soviet space program became available prompting me to start writing about the subject in 1990 to share what I had learned with others (see “The Future that Never Came: Mars 94”).

  Around the same time I published my first article, I found out that the Boston Museum of Science was going to host an exhibit of Soviet space hardware in the summer of 1990. This was just too good of an opportunity to pass up and I made a couple of visits to see it in July with my friend, Larry Klaes (who was a fellow space writer, member of Krasnaya Orbita as well as the editor who got me my start in freelance writing). Not only did we get to talk to some of the Soviet engineers who accompanied the exhibit, but we photographed much of the hardware and its details in order to glean as much information as possible from this opportunity. What follows are a selection of my photographs from that exhibit thirty years ago.

   

  Launch Vehicles & Engines

  One of the first displays which caught my attention in July 1990 was an automated display model of how a Soyuz rocket was erected on its pad at the Baikonur Cosmodrome. In addition to my interest stemming from model railroading, it gave me an opportunity to see the details of how this process worked from multiple angles.

  

  Model of a Soyuz launch vehicle that was part of an animated display. (A.J. LePage)

  

  A montage of photos of an animated display showing the erection of a Soyuz launch vehicle on its pad. Click on image to enlarge. (A.J. LePage)

  In addition to display models of various Soviet launch vehicles, the exhibit also included displays of some rocket engines. The RD-253, which was the largest on display, was used on the first stage of the largest operational Soviet launch vehicle, the Proton-K. Burning the hypergolic propellants UDMH and nitrogen tetroxide, each of the six RD-253 engines generated 1,630 kilonewtons of thrust.

  

  A display model of the RD-253 engine used in the first stage of the Proton-K launch vehicle. (A.J. LePage)

  Another interesting engine (which I had not heard about at that time) was the RD-301. This experimental engine burned the exotic propellant combination of liquid ammonia and highly reactive liquid fluorine to generate 97 kilonewtons of thrust with an I_SP of 400 seconds – comparable to the performance of American cryogenic engines. Originally developed to serve as the propulsion system of a high-energy Proton-K4H upper stage, the project was shelved in 1977.

  

  A model of the experimental RD-301 engine which burned liquid ammonia and liquid fluorine. (A.J. LePage)

   

  Crewed Spaceflight

  One of the eye-opening treats of the exhibit for me was a display of the Soyuz descent module. What struck me was how small the interior volume of this module was especially compared to the Apollo spacecraft which I had already seen on display (including an interactive display at the Boston Museum of Science almost 20 years earlier – see “Plans for a Command Module of My Own”). Also included in the display was not only a dummy in a Sokol spacesuit in a Soyuz seat, but an empty seat which exhibit-goers could sit in. Needless to say, this seat was a very tight fit for my 6’1” frame making me wonder how I would fare even a short trip in a Soyuz.

  

  A display of the Soyuz descent module. In front is a dummy in a Soyuz seat wearing a Sokol spacesuit. (A.J. LePage)

  

  A peek inside the Soyuz descent module. (A.J. LePage)

  

  Another view of the Soyuz interior showing the second seat position. (A.J. LePage)

  Other items on display included Soviet space suits. One was the Sokol space suit used by cosmonauts flying Soyuz while another was a Berkut suit of the type used by Alexei Leonov during the first EVA in March 1965 (see “The Mission of Voskhod 2”).

  

  Display of the Soviet Berkut spacesuit used for the Voskhod 2 EVA (left) and the Sokol worn by cosmonauts on the Soyuz. (A.J. LePage)

  Another interesting display was an Orlan EVA suit and the SPK – the Soviet equivalent of NASA’s Manned Maneuvering Unit (MMU). The SPK was carried on the then-new Mir space station and had been tested during a pair of EVAs in 1990.

  

  A view of a dummy wearing an Orlan EVA suit with an SVK manned maneuvering unit tested on Mir in 1990. (A.J. LePage)

  

  A face-on, closeup of the Orlan and SVK. (A.J. LePage)

   

  Lunar & Planetary Missions

  By far, the part of the display that was of greatest interest to me in this 1990 exhibit was the displays of Soviet lunar and planetary hardware. After seeing models of American lunar and planetary spacecraft during the previous decade, I was struck by the size of these Soviet spacecraft. Prominently displayed was a model of the Lunokhod 2 lunar rover which explored LeMonnier Crater in 1973. It would be years later that I discovered that this rover also carried an astrophotometer to assess the possibility that the lunar surface would be a suitable site for an observatory (see “The Original Lunar Observatories”).

  

  A display of the Lunokhod 2 lunar rover. (A.J. LePage)

  

  A rear view of the Lunkohod 2 lunar rover. (A.J. LePage)

  One of the biggest thrills of the exhibit for me was the display of hardware from the Luna 24 mission – the last Soviet lunar sample return mission from August 1976 (see “The Last Lunar Sample Return Mission”). With a wink of consent from one of the Soviet engineers minding the exhibit, I actually got to briefly touch the actual return capsule of the E-8-5M Luna 24 mission. Also on display was an engineering model of the LB-9 drill used to secure a two-meter long core sample of the lunar surface and the mechanism used to stow it in a return container. It would be two years before I got to see an engineering model of the entire E-8-5M spacecraft on display at the National Museum of the USAF in Dayton, Ohio.

  

  The actual Luna 24 return capsule on display. (A.J. LePage)

  

  An engineering model of the KB-9 lunar drill used by the E-8-5M Luna 24 to secure a two-meter long core sample for return to Earth. (A.J. LePage)

  

  A closeup of the head of the KB-9 lunar drill. (A.J. LePage)

  

  The sample container used by the E-8-5M return capsule. (A.J. LePage)

  

  A display of the Soviet E-8-5M sample return spacecraft in July 1992 at the Museum of the USAF in Dayton, Ohio. (A.J. LePage)

  As impressed as I was with the size of some of the Soviet space hardware, I was somewhat surprised by the simplicity and small size of the one-meter diameter Venera 7 lander which landed on the surface of Venus in December 1970.

  

  A model of the Venera 7 descent capsule which landed on Venus in December 1970. (A.J. LePage)

  

  A closeup of the top of the Venera 7 lander. (A.J. LePage)

  Much larger and more impressive was the display of a VEGA spacecraft. The Soviet Union and an international collaboration of scientists flew a pair of VEGA spacecraft to explore Venus using an advanced lander and a long-lived balloon payload when they arrived in June 1985. Following their flyby of Venus, the VEGA spacecraft went on to explore Comet Halley in March 1986 using an array of instruments including a suite carried on a pointable platform (see “The Missions to Comet Halley”).

  

  A model of the Soviet VEGA spacecraft. (A.J. LePage)

  

  A cutaway view of the VEGA descent capsule showing the Venus lander tucked inside. (A.J. LePage)

  

  A view of the Venus balloon payload carried by the VEGA spacecraft. (A.J. LePage)

  

  Closeup view of VEGA’s pointable platform carrying instruments to study Comet Halley. (A.J. LePage)

  Probably the largest spacecraft on display at the 1990 Soviet Space Exhibit was an engineering model of the Phobos spacecraft. A pair of this new generation of planetary spacecraft was launched just two years earlier in July 1988 with the goal of entering orbit around Mars and eventually rendezvousing with the Martian moon, Phobos. Unfortunately, contact with Phobos 1 was lost that September because of a faulty command from ground controllers (see “A Brief History of Planetary Orbit Insertion Failures”). While Phobos 2 made it to Mars, contact was lost in March 1989 just days before its scheduled encounter with the Martian moon. Despite the problems, the design was expected to be used in the Mars 94 mission then under development (see “The Future that Never Came: Mars 94”) while its propulsion system would serve as the basis of the Fregat upper stage.

  

  A model of the Soviet Phobos spacecraft. (A.J. LePage)

  

  A closeup of the core of the Phobos spacecraft. (A.J. LePage)

  

  A closeup of the propulsion module of the Phobos spacecraft. (A.J. LePage)

   

  Science Missions

  Wrapping up what I saw at the 1990 Soviet Space Exhibit were some unmanned science satellites. One of these was an engineering model of the International Astrophysical Observatory Granat based on the highly successful 4V Venera spacecraft. A follow on mission to the highly successful Astron space telescope (see “Astron: Venera Turned Space Telescope”), Granat had been launched a few months earlier in December 1989 carrying a suite of Soviet, French and Dutch instruments to study astronomical X-ray sources.

  

  A model of the International Astrophysical Observatory Granat which was based on the successful Soviet Venera spacecraft. (A.J. LePage)

  Another piece of hardware was a model of the Vostok-based Bion spacecraft used to fly biological experiments in orbit including some supplied by NASA. While configured somewhat differently from the Vostok, it gave me a good sense of the size of this long-lived spacecraft design especially compared to NASA’s Mercury (see “Vostok’s Legacy”).

  

  A model of the Vostok-based Bion spacecraft. (A.J. LePage)

   

  Follow Drew Ex Machina on Facebook.

   

  Related Reading

  “Plans for a Command Module of My Own”, Drew Ex Machina, May 31, 2014 [Post]

  “The Mission of Voskhod 2”, Drew Ex Machina, March 18, 2015 [Post]

  “The Original Lunar Observatories”, Drew Ex Machina, August 21, 2014 [Post]

  “The Last Lunar Sample Return Mission”, Drew Ex Machina, August 18, 2016 [Post]

  “The Missions to Comet Halley”, Drew Ex Machina, March 6, 2016 [Post]

  “A Brief History of Planetary Orbit Insertion Failures”, Drew Ex Machina, February 13, 2010 [Post]

  “The Future that Never Came: Mars 94”, Drew Ex Machina, March 1, 2015 [Post]

  “Astron: Venera Turned Space Telescope”, Drew Ex Machina, January 7, 2016 [Post]

  “Vostok’s Legacy”, Drew Ex Machina, April 12, 2015 [Post]

   

• Oshpark Qwiic GPIO expander based on PCF8574

  Greg Steiert (@fpgahelper) has shared this Qwiic GPIO expander on Hackaday.io:

  

  QGPIO: Qwiic GPIO expander based on PCF8574

  This is a handy general purpose input/output Qwiic board. It provides 8 GPIO each with an LED indicator, and goes to a pin in a dual row 100mil header. The LEDs provides a nice visual output. The second row on the header is grounded, so jumpers can be used to drive the pins low for basic inputs. The 100mil pitch headers are also convenient for connecting to external circuits as well. The interrupt and VCC pins also have their own LEDs and header pins. There are two Qwiic connectors for pass through connections.

  

• Bruce Schneier Traffic Analysis of Home Security Cameras

  Interesting research on home security cameras with cloud storage. Basically, attackers can learn very basic information about what's going on in front of the camera, and infer when there is someone home.

  News article.

  Slashdot thread.

• DragonflyBSD Blog Automatic wlan

  Daniel Fojt has fixed something that has bothered me for years: you no longer need to manually create wlan interfaces; devd does it for you.

  Also on:

  Twitter

July 08, 2020

• Arlo July 8, 2020

  What’s up I’m Arlo Cristofaro, the internet’s favorite 14-year-old. Today Eli woke me up at 10:00 to hand me a cassette tape. If you are wondering, it was “Queen: Greatest Hits” or something like that. As he handed me the cassette tape he said “Arlo, your friend is on the phone.” He actually said the name of one of my friends but I will not reveal that. Now, I had heard of this trick before and I was feeling surprisingly awake for having just woken up so I threw the tape at Eli and said “This is a tape, I’m not stupid.” Looking defeated, Eli turned around and went downstairs. That’s the end of my story, but I thought I might just add that I didn’t get out of bed for another 20 minutes after that. SO last week was my birthday and I just wanted to say thank you to all the people who sent me happy birthday wishes or presents. Sometimes both! I had a really fun day, and all the gifts were great. Today I went on a bike ride and depending on how things go, I may go on another one later. I use this app called “Strava” to track my bike rides and keep track of where I go and I would definitely recommend it. This isn’t sponsored by the way but if you end up getting the app you can follow me, my name is Arlo Cristofaro. Well, thanks for reading todays po- WAIT! There has been an update regarding Fantastic Mr. Fox! My Blu-Ray has been processed and shipped! It is coming from Toronto and I just found out yesterday so hopefully it will be here in a few days to a week. I am excited and when I get it I will post pictures on my website. Thanks for reading and I hope everyone has a great day/week/time until I write again. Bye for now!

• The Atlantic: In Focus Photos: Deadly Flooding in Japan (23 photos)

  Days of torrential rainfall in central Japan have led to extensive flooding and mudslides, leaving as many as 58 people dead so far. Rivers that overflowed their banks have swept away bridges and roads, cutting off communities and making it difficult for rescue workers to reach many areas. Emergency crews are now working against the clock, trying to find people who may still be trapped.

  

  
• Quanta Magazine How and Why Computers Roll Loaded Dice

  Here’s a deceptively simple exercise: Come up with a random phone number. Seven digits in a sequence, chosen so that every digit is equally likely, and so that your choice of one digit doesn’t affect the next. Odds are, you can’t. (But don’t take my word for it: Studies dating back to the 1950s reveal how mathematically nonrandom we are, even if we don’t recognize it.)

  Don’t take it to heart. Computers don’t generate randomness well, either. They’re not supposed to: Computer software and hardware run on Boolean logic, not probability. “The culture of computing is centered on determinism,” said Vikash Mansinghka, who runs the Probabilistic Computing Project at the Massachusetts Institute of Technology, “and that shows up at pretty much every level.”

  But computer scientists want programs that can handle randomness because sometimes that’s what a problem requires. Over the years, some have developed sleek new algorithms that, while they don’t themselves generate random numbers, offer clever and efficient ways to use and manipulate randomness. One of the most recent efforts comes from Mansinghka’s group at MIT, which will present an algorithm called Fast Loaded Dice Roller, or FLDR, at the online International Conference on Artificial Intelligence and Statistics this August.

  Simply put, FLDR uses a random sequence to perfectly simulate the rolling of a loaded die. (Or a weighted coin, or a rigged card deck.) “It shows how to change a perfectly random coin toss into a biased coin toss,” said the mathematician Peter Bierhorst of the University of New Orleans. Bierhorst did not contribute to the research but describes the premise behind FLDR’s success as “compelling.”

  FLDR won’t give you an edge in Monopoly or boost your odds at Las Vegas craps tables. But its creators say it suggests a way to integrate random numbers into software and hardware, which are built to be deterministic. Incorporating this kind of uncertainty will help machines make humanlike predictions and better simulate phenomena that rely on probability like the climate or financial markets.

  Randomness is a trickier concept than it seems. In sequences of random numbers, where there’s no discernible pattern, every digit has the same probability of showing up. Pi itself is not a random number, for example, but the digits of pi are believed to be random in this way (what mathematicians describe as “normal”): Every integer from 0 to 9 appears about the same number of times.

  Even though you can find a “random number generator” in Google, pure randomness is not what you get. Today’s processors, search engines and password generators use “pseudorandom” approaches that are close enough for most purposes. They’re generated according to complicated formulas, but in theory if you knew the formula, you could likely predict the sequence.

  Scientists have tried to build actual randomness into machines for at least 80 years. (Before then, random numbers came from old standbys like rolled dice, numbered balls picked from a well-mixed bag or other mechanical exercises. In 1927, a statistician sampled census data to produce a table of 40,000 random digits.)

  Early sources of random numbers were physical machines. The first random number-generating machine was the brainchild of the British statisticians Maurice George Kendall and Bernard Babington Smith, who described it in 1938. The machine was placed in a dark room, where it spun a disk divided into 10 equal wedge-shaped pieces labeled 0 to 9. When someone tapped a key at erratic intervals, a brief neon flash or spark would illuminate the disk so that it appeared to freeze, with only one number visible. A later machine, called Ernie, used signal noise in neon tubes instead; starting in 1957 it chose the winning numbers in a British lottery.

  More recently, for truly random sequences, Bierhorst says, computer scientists have to look to natural phenomena like the cosmic background radiation or the unpredictable behaviors of quantum systems. “There are random processes in nature that can be harnessed that are truly unpredictable,” he said. “The electron that dodges to the left or to the right doesn’t even know what it’s going to do beforehand.”

  But randomness can only take you so far. By the late 1940s, physicists began generating random numbers to fit a given probability distribution. Such tools — a theoretical version of rolling a loaded die — could more accurately be used to model real-world situations, like traffic flow or chemical reactions. In 1976, the pioneering computer scientists Donald Knuth and Andrew Yao introduced an algorithm that could use a string of random numbers to produce random samplings of any array of weighted outcomes. “It was the most time-efficient algorithm one could ever arrive at,” said Feras Saad, a doctoral student in Mansinghka’s lab who led the new work on FLDR.

  Unfortunately, Saad says the algorithm makes a trade-off that’s well known to computer scientists: Many applications that run quickly use a lot of memory, and applications that use little memory can have a long runtime. Knuth and Yao’s algorithm falls into the first category, making it elegant but too memory-intensive for any practical use.

  But last spring, Saad spotted a clever workaround. He realized that when the weights on a die added up to a power of 2, the algorithm was efficient in both time and memory. So for a six-sided die, imagine that the odds of rolling the numbers 1 through 6, respectively, are weighted at 1, 2, 3, 4, 5 and 1. That means the probability of rolling a 1, for example, is 1/16, and the probability of rolling a 2 is 2/16. Since the weights add up to a power of 2 — 16 is 2⁴ — the algorithm for this system is efficient in time and memory.

  But imagine that the weights are instead 1, 2, 3, 2, 4, 2, which sum to 14. Since 14 is not a power of 2, the Knuth-Yao algorithm requires significantly more memory. Saad realized he could include an additional weight so that they always summed to a power of 2. In this case, he would simply add another hypothetical face — one with weight 2 — so that the weights added up to 16. If the algorithm chose one of the original faces, the value was recorded. If it chose the extra face, the value was discarded, and the algorithm was run again.

  This is the key to FLDR’s efficiency, making it a powerful tool in simulations: The amount of extra memory needed for the additional rolls is minimal compared to the hefty memory usually required in the original.

  FLDR makes the Knuth-Yao algorithm efficient and suggests ways to improve a wide swath of applications. Climate change simulations, crop yield predictions, particle behavior simulations, financial market models and even the detecting of underground detonations of nuclear weapons depend on random numbers in weighted probability distributions. Random numbers also form the backbone of cryptography schemes that protect data sent over the internet.

  Mansinghka says FLDR may also help researchers find ways to integrate probability into computer processors — the focus of his lab’s work at MIT. The algorithm could help inform the design of software libraries and new hardware architectures that can generate random numbers and use them in efficient ways. That would be a dramatic departure from the deterministic Boolean machines we’re used to.

  “We might be very well positioned to integrate randomness into the building blocks of software and hardware,” he said.

• Centauri Dreams Building the Psyche Asteroid Explorer

  If all goes well (an often perilous assumption, as JWST so frequently reminds us), NASA’s Psyche mission to the intriguing asteroid of the same name will lift off in about two years. We’re now moving out of the design and planning stage into manufacturing the spacecraft hardware, this following a period of testing on the core engineering models that will deliver the spacecraft to its target in the main asteroid belt. The critical design review, a shakeout of the three science instruments and engineering subsystems, has just been passed with flying colors.

  

  Principal investigator Lindy Elkins-Tanton (Arizona State University) calls the process “one of the most intense reviews a mission goes through in its entire life cycle.” True enough, as everything from telecommunications, power and propulsion must pass the test, not to mention the flight avionics and computing systems. We’re a long way past the digital blueprint stage, having followed it up with prototypes and engineering models of the science instruments and engineering subsystems, all performed before the flight hardware could be built.

  “This is planning on steroids” said Elkins-Tanton. “And it includes trying to understand down to seven or eight levels of detail exactly how everything on the spacecraft has to work together to ensure we can measure our science, gather our data and send all the data back to Earth. The complexity is mind-boggling.”

  So what’s next? Assembling and testing of the full spacecraft is to begin in February of 2021, with a deadline of April 2021 for each instrument to be delivered to the main clean room at the Jet Propulsion Laboratory. This is going to be a fascinating mission to watch from the technology standpoint, as it will involve a demonstration of the Deep Space Optical Communications system (DSOC), intended to improve communications performance by 10 to 100 times without corresponding increases in mass, volume or power.

  We’re going to want to follow DSOC closely because of its deep space implications. The plan is to deploy advanced lasers in the near infrared, and a look through NASA materials on the project shows three technologies — a low-mass spacecraft pointing assembly; a flight laser transmitter; and a pair of photon-counting detector arrays — being integrated into the DSOC system, communicating with a ground-based receiver to enable efficient communications. All this by way of exploring a future that will one day demand high-definition imagery, live video feeds and real-time data transmission for long-duration missions to deep space.

  So while it’s a demonstrator, DSOC is an important one, and the Psyche mission offers a test of the system’s ability to cull faint laser signals out of a noisy background. Beyond DSOC, engineers at Maxar Technologies in Palo Alto (CA) are building the main body of the spacecraft (the Solar Electric Propulsion Chassis), attaching propulsion tanks enroute to delivery early next year to JPL, followed not long after by the solar arrays critical to power the spacecraft’s systems.

  The avionics subsystem is being built at JPL, where Psyche Project Manager Henry Stone notes:

  “One of the things we pride ourselves on in these deep-space missions is the reliability of the hardware. The integrated system is so sophisticated that comprehensive testing is critical. You do robustness tests, stress tests, as much testing as you can – over and above. You want to expose and correct every problem and bug now. Because after launch, you cannot go fix the hardware.”

  Imagine having a job where you can talk about your involvement in multiple deep space missions, the kind of thing that makes me wish for a quick rejuvenation and a new career doing exactly that at places like JPL. And then to watch the mission fly… Psyche is to launch in August of 2022, with a Mars gravity assist in May of 2023 and arrival at Psyche in 2026.

  

  Image: This artist’s concept, updated as of June 2020, depicts NASA’s Psyche spacecraft. Set to launch in August 2022, the Psyche mission will explore a metal-rich asteroid of the same name that lies in the main asteroid belt between Mars and Jupiter. The spacecraft will arrive in early 2026 and orbit the asteroid for nearly two years to investigate its composition. Credit: NASA/JPL-Caltech/ASU/Peter Rubin.

  What an interesting destination we’re dealing with. Psyche is made up mostly of iron and nickel, making it much like Earth’s core, so we may be looking at the stripped core of a differentiated planetesimal, unless the asteroid formed as a body rich in iron. If its mantle was stripped away, when did that occur, and how? Exactly how will this asteroid compare to known stony, icy objects we’ve visited? We can’t see planetary cores, but Psyche may give us a look into a planetesimal core from the era of collisions and accretion that produced the terrestrial planets.

  The spacecraft will fly with a magnetometer to measure the asteroid’s magnetic field, along with a multispectral imager to collect images and data about the object’s composition and topography. Spectrometers will analyze the surface to determine its chemical abundances. The propulsion system is an electric hall thruster using xenon as the propellant. ATLO is next — Assembly, Test and Launch Operations — all beginning in February of next year. Love those NASA acronyms!

  

  

  
• Bruce Schneier Half a Million IoT Passwords Leaked

  It is amazing that this sort of thing can still happen:

  ...the list was compiled by scanning the entire internet for devices that were exposing their Telnet port. The hacker then tried using (1) factory-set default usernames and passwords, or (2) custom, but easy-to-guess password combinations.

  Telnet? Default passwords? In 2020?

  We have a long way to go to secure the IoT.

• Oshpark Give the gift of a personalized PCB keychain

  From n°Garage offers personalized one square-inch keychains on Tindie:

  

  n°Keychain

  This n°Keychain family consists of a series of one-square-inch keychains or pendants. These little beauties are perfect gifts for festival, graduation and remembrance. And more, write lovely words to make it unique and personal.

  One order will have two keychains or pendants. To customize it, please choose the option from the drop down above if you would like to add personalized text.

  • Background Words(0~15chars): BRAVE / KIND / Curious / Hindsight 2020
  • Time Mark (0~15chars): Happy New Year / Happy Birthday / Class 2020
  • Name Tag (0~25chars): Alice / Rob / Queen Elizabeth School

  If ordering the customizable option, please leave the details of the above inside the field of Additional Instructions at checkout. Please do not exceed the maximum number of characters for each field.

  For personalized keychain, it may take about 5 to 9 workdays to ship after ordering. An email notification will be sent to you once shipped. Usually the shipping takes about 10 work-days.

• Bunnie Huang A Near-Ultrasound (NUS) Data Link

  We were requested to investigate “near ultrasound” (NUS) links as part of our research on developing the Simmel reference design for a privacy-preserving COVID-19 contact tracing device. After a month of poking at it, the TL;DR is that, as suspected, the physics of NUS is not conducive to reliable contact tracing. While BLE has the problem that you have too many false positive contacts, NUS has the problem of too many false negatives: pockets, purses, and your own body can effectively block the signal.

  That being said, we did develop a pretty decent-performing NUS data link, so we’ve packed up what we did into an open source reference design that you can clone and use in your own projects.

  
  Top trace: demodulated data at 1 meter, 50dB background noise. Bottom trace: raw signal, normalized so it is visible. Without normalization the trace just looks like a flat line.

  I imagine one use for this would be a way to provision IoT devices: the “how do I get wifi credentials into an IoT device that lacks both screen and keyboard?” problem. With the addition of a ~$1 microphone to a Cortex-M4 class device, you get a short-range data link to a host device, such as a phone. You can use a web page (via Javascript) to generate the modulated audio directly (relevant example), thus bypassing a host of multi-platform issues, or you can generate a file off-line and send it to any standard music player.

  The TL;DR on the link is it uses a 20,833Hz carrier modulated with BPSK. We use PSK31 coding, so our baud rate is ~651 symbols per second (this is the 1/0 symbol rate before Varicode encoding). This isn’t breaking any speed records, but it’s good enough to send a UUID and some keys over the air in a couple seconds. Tests show decent performance over a distance of 1 meter with about 60dB ambient noise (normal conversation or background music playing at the same time).

  

  The demodulator uses a Costas loop. We’ve documented its details, including comments on porting to other chipsets than the NRF52.

  We also have a reference modulator using a non-linear transducer (e.g. a piezo element), which uses some of the more advanced features of the NRF52 PWM block to eliminate audible sidebands. We also have a rough C program to generate a .wav file, which needs to be run through a high-pass filter using e.g. Audacity to eliminate the low-frequency modulation sidebands; but the resulting .wav file can be played directly on your smartphone and it will demodulate correctly.

  
  Acknowledgements: Sean ‘xobs’ Cross is an equal contributor to this research. This research is funded through the NGI0 PET Fund, a fund established by NLnet with financial support from the European Commission’s Next Generation Internet programme, under the aegis of DG Communications Networks, Content and Technology under grant agreement No 825310.

• Exosky.net The new Jupiter Apparition

  Observers in the southern hemisphere have been having a wonderful apparition for imaging Jupiter. Not so much up here at mid-northern latitudes where Jupiter only rises to about 28 degrees this year. Nevertheless, thanks to the new generation of cameras, software, and magic pixie dust, I’ll be trying to image the great gas giant as often as the weather permits.

  That said, here are some images from recent sessions. A good bit of seeing on July 1, and some fair seeing on July 6.

  

  

• Jetson Hacks JetPack 4.4 Production Release

  JetPack 4.4 – L4T R32.4.3 is now available!

  NVIDIA announces today that the production version of JetPack 4.4 is now available. JetPack 4.4 replaces the current JetPack 4.3 as the production version.

  

  There are many upgrades and new features. Here’s the official blurb from NVIDIA:

  We are pleased to announce the JetPack 4.4 production release 1 supporting Jetson AGX Xavier series, Jetson Xavier NX, Jetson TX2 series, Jetson TX1, and Jetson Nano. (JetPack 4.4 replaces JetPack 4.3 as the latest production release.)

  The JetPack 4.4 production release builds on top JetPack 4.4 Developer Preview, and includes production versions of TensorRT 7.1 and cuDNN 8.0.

  Along with JetPack 4.4, we are introducing a web based Power Estimator tool 2 to simplify creation of custom nvpmodel power profiles for Jetson.

  Please refer to the JetPack Release Notes 1 and L4T Release Notes for additional info.

  JetPack 4.4 Highlights:

  • Support for the new Jetson Xavier NX module 1 and Jetson Xavier NX Developer Kit
  • Support for CUDA 10.2, and TensorRT 7.1.3 and cuDNN 8.0.0
  • Support for Vulkan 1.2 1 and VPI 0.3 1 (Developer Preview)
  • Support for upgrading JetPack and L4T using Debian package management tool
  • Support for Generic Timestamping Engine (GTE) for Jetson AGX Xavier and Jetson Xavier NX
  • Support for Dynamic Frequency Scaling (DFS) for Video Image Compositor (VIC) using actmon
  • SE (Security Engine) samples to demonstrate hardware backed authentication and encryption capabilities of Jetson TX2 series, Jetson AGX Xavier and Jetson Xavier NX modules.
  • Utility to fuse multiple Jetson modules simultaneously
  • Option to specify APP partition size on the microSD card during initial configuration at first boot of Jetson Nano Developer Kit

  JetPack 4.4 components:

  • L4T R32.4.3
  • CUDA 10.2
  • cuDNN 8.0.0
  • TensorRT 7.1.3
  • VisionWorks 1.6
  • OpenCV 4.1
  • Vulkan 1.2
  • VPI 0.3 (Developer Preview)
  • Nsight Systems 2020.2
  • Nsight Graphics 2020.1
  • Nsight Compute 2019.3

  Existing installations of JetPack 4.4 Developer Preview and JetPack 4.3 can be upgraded in-place to the JetPack 4.4 production release without re-flashing the device. For more information about upgrading JetPack via the Debian package management tool, please refer to the JetPack documentation here 1.

  Download JetPack…https://developer.nvidia.com/embedded/jetpack 1

  JetPack Release Notes…https://docs.nvidia.com/jetson/jetpack/release-notes/index.html 1

  L4T Release Notes…https://developer.nvidia.com/embedded/secure/tools/files/jetpack-sdks/jetpack-4.4-ga/Jetson_Linux_Driver_Package_Release_Notes_R32.4.3_GA.pdf

  Go check it out!

  The post JetPack 4.4 Production Release appeared first on JetsonHacks.

• XKCD Acceptable Risk
  
• DragonflyBSD Blog Games still go

  I am entertained by the notion that adventure(6), backgammon(6), battlestar(6), hack(6) and trek(6) can still get updates.  I did not know, incidentally, that sendmail and trek share an author.

  Also on:

  Twitter

• Basic Instructions How to Discuss a Movie Without Spoiling It

  

  Shameful admission time. I have only ever seen The Evil Dead once, and I never saw the modern remake. I kind of consider The Evil Dead 2 to not be a sequel so much as a second draft.

  The movie I want to see is a documentary about the period of time in the early ’80s when Bruce Campbell and Sam Rami shared an apartment with the Coen Brothers, Francis McDormand, Holly Hunter, and Kathy Bates. That’s a lot of talent and strong personalities in a confined space. There must be some great stories there.

  As always, thanks for using my Amazon Affiliate links (US, UK, Canada).

July 07, 2020

• WB4SON Renaming Audio In/Out in Win 10

  As I slowly change from older generation radios to newer ones, many of them come with a USB interface for Rig Control as well as modulation In and Out.  The trouble is that the vendors don’t do a good job of identifying which audio device is which (Kudos to FlexRadio which does, by the way — thumbs down to Icom, Kenwood, and Yaesu who do not).

  For example,

  • K3s Modulation Output “Speakers USB Audio CODEC”
  • K3s Modulation Input “Microphone USB Audio CODEC”
  • FTDX101MP Modulation Output “LINE USB AUDIO CODEC”
  • FTDX101MP Modulation Input “Microphone USB AUDIO CODEC”

  Those names are not very descriptive and leads to confusion when picking an audio device for WSJT-X, FLDIGI, etc.  You CAN rename the devices, after they are installed, using the Windows 10 Control Panel/Hardware and Sound/Sound.  For the Modulation Output, pick the “Recording” tab.  For Modulation Input, pick the “Playback” tab.

  As an example, suppose I want to rename the “LINE USB AUDIO CODEC” on my FTDX-101MP to identify itself as “FTDX USB AUDIO CODEC”, I chose the Recording Tab (it is the radio Modulation Output, so that feeds the Windows 10 “Recording” inputs), the scroll down until I find the “LINE USB AUDIO CODEC”. Highlight that device, then click Properties, then overwrite the “LINE” name and change it to FDTX101, and press OK. (Pick a new Icon if you like).

  

   

   

• Astro Bob Get Out Of Bed And See Comet NEOWISE, You’ll Be Happy You Did

  

  I thought it was going to be cloudy all week but magically the updated forecast predicted clear skies last night (July 6-7). So of course I went to bed at midnight after observing and photographing noctilucent clouds (7th time this season!) and awoke at 2:30 in pursuit of Comet NEOWISE.

  

  The night was still, humid and foggy. In fact, fog blanketed my little observing site that features a wide-open view to the northeast. So I drove around in search of an “island” of clarity in the fog and luckily found it just in time. It was 3:20 a.m. — the sky was growing brighter in the unstoppable dawn. I set up a tripod with a tracking mount and got out the binoculars.

  Yes, I could see them comet dimly with the naked eye — a delicate streak about 1.5° long with a teeny, tiny “star” for a head. It reminded me of a fading meteor or a punk, one of those smoldering sticks of sawdust used to light firecrackers. But the view in binoculars proved sumptuous. NEOWISE’s head was a bright, yellow pea sprouting an elegant, pale orange tail. The way the tail swept back, arching toward the star Theta Aurigae, made my heart melt. Just beautiful.

  

  Way off to the right of NEOWISE I could see Venus and near it the star Aldebaran in Taurus. Comparing the comet to Aldebaran (magnitude 0.9) I estimated the comet’s brightness at magnitude 1.4, by far the brightest comet to grace our skies since Comet PanSTARRS (C/2011 L4) in March 2013.

  I first saw NEOWISE in binoculars around 3:10 a.m. very, very low through the fog. By 3:25 a.m. (2 hours before local sunrise) I could easily spot it with the naked eye. I don’t want to give you the impression it was super-easy to see — you had to know where to look — but once seen I never lost it. And though the sky grew brighter and brighter, it was partly offset by the comet climbing higher and higher. I was able to follow it with my eyes till about 4:15 a.m. and in binoculars until 4:35 a.m., only 45 minutes before sunrise.

  

  I also looked at it through a portable 10-inch telescope. The colors were even more intense, and the tail was clearly bifurcated — split in two with a dark channel separating both halves. I could also see the split in binoculars. It’s unclear to me at the moment how the dark channel forms. But it seems to happen in comets that are actively producing massive quantities of dust whether because they’ve passed close to the sun or due to cracks that cause outbursts of fresh material.

  I want you to see Comet NEOWISE while it is brightest and best. Nothing would make me happier. So set your alarm to go out about 2 hours before sunrise. You’ll need to find a spot in advance with a good view low down in the northeastern sky. You key guide star is the unmistakeable Capella in the constellation Auriga, located nearly 2 fists high at the start of dawn. Start there and use the map below to get there. Remember that the comet will appear as a dim streak with the naked eye (at least at the moment) but much nicer in binoculars or a small telescope.

  

  Starting about July 11 (Saturday) the comet will start to transition into the evening sky. I’ll have a fresh map to help you find it then, too. While you absolutely don’t need a telescope by all means bring binoculars. I hope the sight will thrill you as much as it did me.

• Oshpark Build Your Own RF Lab: Scalar Network Analyzer

  Whitney Knitter writes on Hackster about a simple scalar network analyzer that can be controlled by a Raspberry Pi for measuring the frequency response of filters and networks:

  

  Build Your Own RF Lab: Scalar Network Analyzer

  With the popularity of wireless applications having become such a staple in the hobbyist community, the need for RF testing capabilities in the hobbyist realm has also increased. Anyone familiar with traditional RF test equipment knows that it is expensive. But challenges like this are what bring out the engineering creativity in this community. Steven Merrifield designed and laid out his own simple scalar network analyzer (SNA) using just a few IC chips. SNAs are handy for testing the frequency response of filters or networks.

  A scalar network analyzer is used to test the amplitude of a device’s frequency response by outputting a sine wave sweeping over a certain frequency range (bandwidth) then measuring the amplitude of each incremental output frequency.

  Thus if you directly connect the sine wave output of an SNA to its measurement input, then it will read a flat line of the same amplitude for each incremental output frequency of the sweep:

  

  Merrifield’s SNA has a 30MHz bandwidth as demonstrated in shorting the SNA’s terminals.

  When a device is connected to the SNA, the amplitude of the sine wave at each frequency after going through the device will reflect the device’s frequency response over that bandwidth.

  Merrifield’s design accomplishes an SNA’s functionality via implementation of a DDS Synthesizer chip, an ADC, and a logarithmic amplifier chip. The AD9850 DDS is responsible for outputting the sweeping sine wave while the AD8307 logarithmic amplifier conditions the signal input into the SNA for the log of the signal’s envelope before passing it on to the ADC for digitizing. A second AD8307 also conditions the output of the DDS and outputs it to a second channel of the ADC so that it can be used in software for compensation of any variations on the DDS’s output due to the effects of various loads of devices being tested.

  

  A 10Hz to 30MHz sweep done using a Raspberry Pi to control the SNA.

  The ADC outputs its digital measurements via an I2C interface to a GPIO header that matches the Raspberry Pi’s GPIO header pinout, but any desired MCU or FPGA could be used. The source code Merrifield wrote is in C, making it easy for porting across different platforms.

  

  The SNA with added shielding, cut from 0.5mm copper sheet.

  Check out Merrifield’s project logs here. He linked his PCB layout on OSH Park if you’re interested in ordering it and putting one of these together for your own lab!

• Loren Grush House budget bill denies major increases for NASA to fund ambitious Moon program
  An artistic rendering of astronauts on the Moon, mining resources. | Image: NASA

  House appropriators don’t intend to substantially increase NASA’s budget, potentially jeopardizing the agency’s plans of sending astronauts back to the Moon by 2024.

  Today, the House Appropriations Committee released its latest funding bill for fiscal year 2021, detailing the budgets for all commerce, justice, and science agencies in the US. The bill would give NASA a total budget of $22.63 billion for next year, the same amount the agency received for 2020. However, it’s nearly $3 billion less than the $25.2 billion the Trump administration called for in the president’s budget request — a hefty amount intended to fund an ambitious lunar return.

  NASA has been very vocal about its goal to send the first woman and the next man to the Moon...

  Continue reading…

• The Atlantic: In Focus The Colorful Blooms of Castelluccio, Italy (14 photos)

  In central Italy, the small village of Castelluccio sits atop a hill overlooking the Piano Grande—a broad basin surrounded by the Sibillini Mountains—where fields of lentils and poppies bloom every year, carpeting the landscape with a colorful quilt of blossoming flowers. Every summer the phenomenon is viewed by thousands of tourists, and this year, the photographers Antonio Masiello and Tiziana Fabi visited the fields, sending back these photos.

  

  
• Centauri Dreams KELT-9b: ‘Gravity Darkening’ and an Asymmetric Light Curve

  Perhaps the hottest planet ever discovered spotlights yet another way to interpret light curves produced by transiting worlds. KELT-9b comes out of data gathered by the KELT transit survey, the acronym standing for Kilodegree Extremely Little Telescope. KELT consists of two robotic telescopes, one at Winer Observatory in southeastern Arizona, the other at the South African Astronomical Observatory in Sutherland, South Africa. The planet orbits an A-class star in Cygnus about 670 light years away and turned up in the KELT data in 2017.

  We’ve learned a lot more about KELT-9b thanks to the TESS mission, allowing us to understand just how unusual this planet is. 2.9 times as massive as Jupiter, the world orbits its star in 36 hours, receiving 44,000 times the energy from its host that Earth receives from the Sun. Reaching 4,300 degrees Celsius, this is a tidally locked planet whose dayside is hotter than the surfaces of some stars. Its orbital path takes it almost directly above both the star’s poles.

  But this mix gets even more intriguing. The primary, KELT-9, is roughly twice the size of the Sun, 56 percent hotter, and spins 38 times as fast. That makes for a complete stellar rotation in 16 hours. As you would imagine, the rapid spin causes the star to deform, flattening at the poles and broadening at the equator. As a result, we run into the phenomenon known as gravity darkening — the poles brighten as the equatorial region cools and dims by comparison.

  We get a temperature differential of almost 800 degrees Celsius. The effects on the transit light curve are interesting. Beginning near the star’s poles, the transit blocks less light as KELT-9b travels over the stellar equator. We have an asymmetry here we can work with to gain information about the temperature and brightness changes over the surface of the star, learning more about its shape and orientation.

  Jason Barnes (University of Idaho) is a co-author of the paper on this work:

  “Of the planetary systems that we’ve studied via gravity darkening, the effects on KELT-9 b are by far the most spectacular. This work goes a long way toward unifying gravity darkening with other techniques that measure planetary alignment, which in the end we hope will tease out secrets about the formation and evolutionary history of planets around high-mass stars.”

  

  Image: Observations from NASA’s Transiting Exoplanet Survey Satellite (TESS) have revealed new details about KELT-9b’s environment. The planet follows a close, polar orbit around a squashed star with different surface temperatures, factors that make peculiar seasons for KELT-9b. The planet’s transits begin near one of the star’s hot, bright poles and progress toward the cooler, dimmer equator. Credit: NASA’s Goddard Space Flight Center.

  Depending on which part of the star is being referenced, the phenomenon behind gravity darkening is sometimes called gravity brightening, reflecting the fact that the oblate shape of such a rapidly spinning star causes higher surface gravity at the poles, producing higher temperature and brightness; by contrast, the equator is darker. Because of the temperature differential on the surface of the star, KELT-9b experiences an unusual kind of seasonality, hotter over the poles, colder over the star’s equator. A kind of summer, a kind of winter, with each season lasting nine hours, only to repeat during the brief year.

  A planet like this is going to be useful for research into hot Jupiters. There is a clear trend among such worlds in that they are often spin-orbit misaligned. The paper continues:

  “Its high dayside temperature provides excellent opportunities for phase curve and secondary eclipse analyses (Hooton et al. 2018; Wong et al. 2019; Mansfield et al. 2020). The high signal-to-noise ratio of its transit makes KELT-9 b a top target for transmission spectroscopy (Hoeijmakers et al. 2018, 2019; Cauley et al. 2019). In this work, we model KELT-9 b’s Transiting Exoplanet Survey Satellite (TESS) light curve including rapid stellar rotation to measure the hot Jupiter’s transit parameters, and we take advantage of the transit asymmetry caused by gravity darkening to robustly constrain the planet’s orbital geometry including its true spin–orbit orientation.

  Thus this paper is unusual in being one of the few that deal with gravity darkening in analyzing an exoplanet lightcurve. Using it, the authors measure the planet’s alignment angle and discuss the effects of gravity darkening on the hot Jupiter’s atmospheric processes. In the figure below, the effects of gravity darkening are apparent in the transit.

  

  Image: This is Figure 2 from the paper. Caption: (Left) KELT-9 b begins its transit near the star’s hot pole and moves toward the star’s cooler equator. Our transit analysis directly measures the stellar inclination ( i ), the planet’s projected alignment (λ), and the orbital inclination (i.e., the impact parameter b). We find that KELT-9 varies in effective temperature by ∼800 K between its hot poles and cooler equator. (Right) KELT-9 b’s phase-folded primary transit from TESS. The transit depth steadily decreases throughout the eclipse, indicating that KELT-9 b begins its transit near one of the host star’s hotter poles and moves toward the dimmer stellar equator. Credit: Ahlers et al.

  Models of rapidly rotating stars are still being developed, but will be needed to analyze the high number of such stars expected to be discovered by TESS. In fact, I was surprised to learn that in a previous paper, lead author John Ahlers (NASA GSFC) had estimated on the order of 2,000 exoplanets will turn up orbiting A/F stars in the TESS data, and the expectation is that a large number of these will be spin-orbit misaligned. Thus KELT-9b gives us a window into fast rotators, which are expected to comprise a large number of the A/F systems discovered.

  The paper is Ahlers et al., “KELT-9 b’s Asymmetric TESS Transit Caused by Rapid Stellar Rotation and Spin–Orbit Misalignment,” The Astronomical Journal Vol. 160, No. 1 (5 June 2020). Abstract.

  

  

  
• Bruce Schneier IoT Security Principles

  The BSA -- also known as the Software Alliance, formerly the Business Software Alliance (which explains the acronym) -- is an industry lobbying group. They just published "Policy Principles for Building a Secure and Trustworthy Internet of Things."

  They call for:
  

  • Distinguishing between consumer and industrial IoT.
    
  • Offering incentives for integrating security.
    
  • Harmonizing national and international policies.
    
  • Establishing regularly updated baseline security requirements

  As with pretty much everything else, you can assume that if an industry lobbying group is in favor of it, then it doesn't go far enough.

  And if you need more security and privacy principles for the IoT, here's a list of over twenty.

• Quanta Magazine Why Is Glass Rigid? Signs of Its Secret Structure Emerge.

  Most materials derive their macroscopic properties from their microscopic structure. A steel rod is hard, for instance, because its atoms form a repeating crystalline pattern that remains static over time. Water parts around your foot when you dip it into a lake because fluids don’t have that structure; their molecules move around randomly.

  Then there’s glass, a strange in-between substance that has puzzled physicists for decades. Take a snapshot of the molecules in glass, and they’ll appear disordered just like a liquid’s. But most of the molecules barely move, making the material rigid like a solid.

  Glass is formed by cooling certain liquids. But why the molecules in the liquid slow down so dramatically at a certain temperature, with no obvious corresponding change in their structural arrangement — a phenomenon known as the glass transition — is a major open question.

  Now, researchers at DeepMind, a Google-owned artificial intelligence company, have used AI to study what’s happening to the molecules in glass as it hardens. DeepMind’s artificial neural network was able to predict how the molecules move over extremely long timescales, using only a “snapshot” of their physical arrangement at one moment in time. According to DeepMind’s Victor Bapst, even though the microscopic structure of a glass appears featureless, “the structure is maybe more predictive of the dynamics than people thought.”

  Peter Harrowell, who studies the glass transition at the University of Sydney, agrees. He said the new work “makes a stronger case” than ever before that in glass, “structure somehow encodes for the dynamics,” and so glass isn’t as disordered as a liquid after all.

  Predicting Propensity

  To understand what microscopic changes cause the glass transition, physicists need to relate two kinds of data: how the molecules in a glass are arranged in space, and how they (slowly) move over time. One way to link these is with a quantity called dynamic propensity: how much a set of molecules is likely to have moved by some specific time in the future, given their current positions. This evolving quantity comes from calculating the molecules’ trajectories using Newton’s laws, starting with many different random initial velocities and then averaging the outcomes together.

  By simulating these molecular dynamics, computers can generate “propensity maps” for thousands of glass molecules — but only on timescales of trillionths of a second. And molecules in glass, by definition, move extremely slowly. Computing their propensity to a horizon of seconds or more is “just impossible normal computers because it takes too much time,” said Giulio Biroli, a condensed matter physicist at the École Normale Supérieure in France.

  What’s more, Biroli said, merely turning the crank on these simulations doesn’t produce much insight for physicists about what structural features, if any, could be causing the molecular propensities in glass.

  DeepMind’s researchers set out to train an AI system to predict propensities in glass without actually running the simulations, and to try to understand where these propensities come from. They used a special kind of artificial neural network that takes graphs — collections of nodes connected by lines — as input. Each node in the graph represents a molecule’s three-dimensional position in the glass; lines between nodes represent how far apart molecules are from each other. Since neural networks “learn” by changing their own structure to reflect the structure of their inputs, “the graph neural network is very well suited to represent particles’ interaction,” Bapst said.

  Bapst and his colleagues first used the results of simulations to train their AI system: They created a virtual cube of glass comprising 4,096 molecules, simulated the evolution of the molecules based on 400 unique starting positions at various temperatures, and computed the particles’ propensities in each case. After training the neural network to accurately predict these propensities, the researchers next fed 400 previously unseen particle configurations — “snapshots” of the glass molecules’ configurations — into the trained network.

  Using only these structural snapshots, the neural network predicted the molecules’ propensities at different temperatures with unprecedented accuracy, reaching 463 times further into the future than the previous state-of-the-art machine learning prediction method.

  Correlated Clues

  According to Biroli, the DeepMind neural network’s ability to predict molecules’ future movements based on a mere snapshot of their current structure provides a powerful new way to explore the dynamics of glasses, and potentially other materials as well.

  But what pattern did the network detect in those snapshots in order to make its predictions? The system can’t be easily reverse-engineered to determine what it learned to pay attention to during training — a common problem for researchers trying to use AI to do science. But in this case they found some clues.

  According to Agnieszka Grabska-Barwinska, a member of the team, the graph neural network learned to encode a pattern that physicists call correlation length. That is, as DeepMind’s graph neural network restructured itself to reflect the training data, it came to exhibit the following tendency: When predicting propensities at higher temperatures (where molecular movement looks more liquid-like than solid), for each node’s prediction the network depended on information from neighboring nodes two or three connections away in the graph. But at lower temperatures closer to the glass transition, that number — the correlation length — increased to five.

  “We see that the network extracts, as we lower the temperature, information from larger and larger neighborhoods” of particles, said Thomas Keck, a physicist on the DeepMind team. “At these different temperatures, the glass looks, to the naked eye, just identical. But the network sees something different as we go down.”

  Increased correlation length is a hallmark of phase transitions, in which particles transition from a disordered to an ordered arrangement or vice versa. It happens, for instance, when atoms in a block of iron collectively align so that the block becomes magnetized. As the block approaches this transition, each atom influences atoms farther and farther away in the block.

  To physicists like Biroli, the neural network’s ability to learn about correlation length and factor it into its predictions suggests that some hidden order must be developing in the structure of glass during the glass transition. Peter Wolynes, a glass expert at Rice University, said that the correlation length learned by the machine provides evidence that materials “approach a thermodynamic phase transition” as they become glassy.

  Still, the knowledge gained by the neural network doesn’t easily translate into new equations. “We cannot say, ‘Oh, actually our network is looking at this correlation that I can give you a formula for,’” said Pushmeet Kohli, who heads DeepMind’s science team. To some glass physicists, this caveat limits how useful the graph neural network might be. “Can this be explained in human terms?” said Wolynes. “That they did not do. That doesn’t mean they cannot do it in the future.”

• Avazea (Philly-based data science corp) Maintaining Data on the Curb with CurbLR: A New Open Standard

  CurbLR is a promising new open data specification for curb regulation. We used it to visualize and analyze Philadelphia's curb management approaches affect on traffic.

  The post Maintaining Data on the Curb with CurbLR: A New Open Standard appeared first on Azavea.

• ke9v Spartan Sprint Results

  It’s been nearly a year since I last participated in a Spartan Sprint so I marked my calendar so as not to forget it last night. It was of course, another backyard activation for me using the KX3. It was also a 40 meter only operation. Having setup at 8pm local for the SP which wouldn’t begin for another hour, I had some time to tune around and get the lay of the band.

  The 13 Colonies stations were popping up like dandelions and while I had no interest in collecting them this year, I ended up logging K2A, K2B, K2C, K2K, K2H, K2J, K2L, and WM3PEN. Quick and easy without a single request for a repeat despite the band being in not so good shape.

  When 9pm arrived I moved up in the 7040-7045 range as I recalled from the last time I was in the SP that seemed to be the hangout. But this is also where things got tougher as I was now chasing QRP stations and not the bigger signals from the original colonies.

  I managed to coax a few signals out of the aether. K3RLL was first followed by K3JZD, K4BAI and WB9HFK. And that was it. I hung around until almost 10:30pm local but I never even copied other stations working the event, and you can’t work ‘em if you can’t hear ‘em.

  I’ll send in my results and will be interested to see how everyone did. Usually if I report poor band conditions and only 4 contacts someone else will say the bands were in “great” shape and put 200 Qs in their log! I hate it when that happens…

July 06, 2020

• DragonflyBSD Blog Booting DragonFly on APU2 boards

  If you happen to have an APU2, here’s some tips on the boot process.

  Also on:

  Twitter

• Astro Bob Why Wait For Betelgeuse To Blow Up? See Two Bright Supernovae Tonight

  

  Why wait around for Betelgeuse to blow up to see a supernova in your lifetime? If you have a 6-inch telescope and dark sky you can see one right now. Two actually. Both are visible in the western sky at nightfall in the neighboring constellations Virgo and Coma Berenices.

  The first of the pair, dubbed SN (for supernova) 2020nlb, was discovered by the Asteroid Terrestrial-impact Last Alert System (ATLAS) on June 25 in the 10th magnitude galaxy M85. Located in Coma Berenices 60 million light years from Earth, M85 is an elliptical galaxy a quarter again as large our Milky Way. The “M” stands for Charles Messier, an 18th century French astronomer who compiled a list of galaxies, star clusters and nebulae he stumbled on during searches for his favorite prey, comets.

  

  On July 1, Japanese amateur astronomer and prolific supernova hunter Koichi Itagaki nabbed SN 2020nvb in NGC 4457, a spiral galaxy in Virgo located about 55 million light years away. Each of these newly discovered supernovae occurred in a close double star system where a tiny, superdense white dwarf star orbits a normal star like our sun. The dwarf is only about the size of the Earth, but its matter is packed so tightly it has nearly the same mass as the sun.  You’d need a huge crane to lift even a thimbleful!

  

  The dwarf’s powerful gravity siphons material from its companion onto its surface until the added weight and pressure of the stolen material initiates runaway nuclear fusion within the dwarf and boom! — it explodes cataclysmically as a supernova.

  Like breakfast cereals, supernovas come in a variety of types but are broadly divided into Type Ia (white dwarf explosions in close pairs) and Type II (massive star blasts like Betelgeuse). Both 2020nlb and 2020nvb are Type Ia supernovae, among the brightest “candles” in the universe. In fact, the most luminous supernovae routinely outshine their entire host galaxy! Betelgeuse is a standalone, gigantic star. One day it will run out of nuclear fuel, stop “burning” and then collapse and explode as a supernova as bright as the gibbous moon.

  The M85 supernova has been getting brighter and brighter since discovery and now shines at magnitude 12.2, within the range of a 6-inch telescope from a dark sky. It’s located right next to a 13.1 magnitude Milky Way foreground star a short distance north of the galaxy’s center. The NGC 4457 supernova is even brighter at magnitude 11.9 and located a little northwest of the center of the galaxy’s nucleus.

  

  Now that the moon is past full it’s on its way out of the evening sky, so you’ll have the darkness you’ll need to spot these distant explosions. I encourage you to start looking for the pair as soon as it gets dark when they’re highest in the sky and least affected by the atmosphere. Begin at Denebola, an obvious 2nd magnitude star about two fists (20°) high in the western sky at twilight’s end, and star hop to M85. Then use the photo to identify the supernova. Or use Epsilon Virginis. To reach NGC 4457 start at either Porrima or Eta Virginis in Virgo and use the detailed map below to star hop to this galaxy.

  

  Use your lowest magnification while star-hopping. Once you’ve arrived at each galaxy increase the power to 100x or higher to pick out the supernovae. The next part’s the best. You get to imagine that the point of light you see is actually a star in the process of self-destruction, one of the most powerful and creative acts in the universe. Creative? You bet. Supernovae explosions seed interstellar space with lots of elements including familiar ones like iron, nickel, lead and gold. All that material regathers into great clouds of gas and dust called nebulae within which are born new generations of stars … and planets.

• The Wakes I Leave Tacking to Crystal Bay: First Daysail of the Season

  Here is Sassy Gaffer’s GPS track that proves it all:

  

  On July 4 2020, Sassy Gaffer accepted the invitation of Woodpecker to sail in Lac Desch̻nes. Both sailboats sailed for five hours (8:20 Р13:20 EDT) under sunny skies with the wind steady at 4-8 Kts. from the NW (likely gusting to double that strength).

  The trip covered 9.70 NM in 3:55 hrs underway at an average speed of 2.5 Kts. with a maximum sailing speed of 4.7 Kts. All points of sail were explored with a nice break for a one-hour chat while rafted at the northern tip of Crystal Bay (with each crew remaining in its own vessel and keeping all recommended COVID distances as prescribed by the rules of the Nepean Sailing Club). The raft held tight against wind and waves swinging at Woodpecker’s rode and large anchor.

   Woodpecker was able to try her functional multi-panelled junk-rig sail with multiple mainsheets, each attached to a different batten, an interesting design that allows for full control on the sail twist:

  

  While Sassy sailed full sail with her gaff fully hoisted:

  

  Both boats seemed well matched given the prevailing conditions, and in spite of their different design and rig they were able to keep within a short distance of each other for the duration of the entire trip, which for Sassy Gaffer was her first real daysail of the season.

• ke9v Antenna Work

  The 44-foot Rohn push-up mast finally arrived today. It’s the last bit of hardware I’ve been waiting on to complete my HF antenna upgrade. It will support another center-fed zepp, but this taller support will permit me to cut this one a little longer and I expect it to play well on 80 and 40 meters. That should be valuable for the upcoming fall/winter season.

  Today is the first Monday of the month and that means tonight (local) is the July Spartan Sprint. I’ll be in the fray, hoping to be heard by a few other stations. I haven’t done well in this QRP event for a few years, but tonight could be my lucky night? See you there.

• Quanta Magazine How Your Heart Influences What You Perceive and Fear

  We consider the brain the very center of who we are and what we do: ruler of our senses, master of our movements; generator of thought, keeper of memory. But the brain is also rooted in a body, and the connection between the two goes both ways. If certain internal receptors indicate hunger, for instance, we’re driven to eat; if they indicate cold, we dress more warmly.

  However, decades of research have also shown that those sensations do much more than alert the brain to the body’s immediate concerns and needs. As the heart, lungs, gut and other organs transmit information to the brain, they affect how we perceive and interact with our environment in surprisingly profound ways. Recent studies of the heart in particular have given scientists new insights into the role that the body’s most basic processes play in defining our experience of the world.

  In the late 19th century, the psychologist William James and the physician Carl Lange proposed that emotional states are the brain’s perception of certain bodily changes in response to a stimulus — that a pounding heart or shallow breathing gives rise to emotions like fear or anger rather than vice versa. Researchers have since found many examples of physiological arousal leading to emotional arousal, but they wanted to delve deeper into that link.

  The heartbeat provided the perfect means to do so.

  The Heart Tips the Seesaw

  Cardiac activity can be divided into two phases: systole, when the heart muscle contracts and pumps out blood, followed by diastole, when it relaxes and refills with blood.

  Beginning in the 1930s, scientists found that systole dampens pain and curbs startle reflexes. Further work traced this effect to the fact that during systole, pressure sensors send signals about the heart’s activity to inhibitory regions of the brain. This may be useful because, while the brain must constantly balance and integrate internal and external signals, “you cannot pay attention to everything at once,” said Ofer Perl, a postdoctoral research fellow at the Icahn School of Medicine at Mount Sinai in New York. Experiments even showed that people were more likely to forget words that were presented exactly at systole than words that they saw and encoded during the rest of the cardiac cycle.

  “I really see the senses like a seesaw,” said Sarah Garfinkel, a neuroscientist at Brighton and Sussex Medical School in England and one of the lead investigators on the memory work. “When you’re sensing something from internally, then it dampens down processing of external signals. When your heartbeat is going, then it’s just loading up the seesaw to one side.”

  The heart’s inhibitory effects were demonstrated once again in work published in May in the Proceedings of the National Academy of Sciences. When people were presented with a barely detectable electrical stimulus to their finger, they were more likely to perceive it during diastole and to miss it during systole. Moreover, participants with greater neural responses to cardiac activity were less sensitive to the stimulus. “It’s fascinating that, even in this millisecond range, our perception can change,” said Esra Al, a doctoral student at the Max Planck Institute for Human Cognitive and Brain Sciences and lead author of the study.

  The team noted how the heart might be “loading up the seesaw” in this case. During systole, as the heart pushes blood into the rest of the body, it’s possible to feel your pulse in your fingertips. It’s advantageous for the brain to cancel out those signals since they don’t provide new information about the environment — but in doing so, slight touch sensations might get suppressed, too.

  What doesn’t seem to get suppressed, however, is fear.

  Fear Breaks Through

  In 2014, Garfinkel and her colleagues showed that the processing of fear and threatening stimuli was not inhibited at systole. While systole activated inhibitory brain regions, it also activated the amygdala, an area implicated in the experience of fear. The researchers found that during systole, people tended to perceive fearful faces more intensely. This was not the case for faces expressing a neutral emotion: Study participants rated those as less intense during systole; that processing seemed to get the usual dampening treatment. “What’s most striking about fear is that it breaks through,” Garfinkel said. “It’s impervious to this inhibitory effect of the heart.”

  This is likely to be an adaptive response to the greater number of systoles that fear provokes. “If your heart is beating really strong and fast, and you’re in a fear state, you don’t want to be sensitive to pain. You want to be able to run over broken twigs and glass to escape the threat,” Garfinkel said. “But you want to be hyper-alert to a threat in the environment. … Fear is something that can help you survive.”

  Garfinkel recently found that this link to fear is even stronger than expected. As described in a preprint now under review for publication, she and her team conditioned test subjects to associate some shapes with a mild electric shock, and then presented them with those shapes — as well as more neutral ones — during systole and diastole. The expectation was that people would always exhibit more fear of the shapes associated with the shock. Instead, the participants responded more fearfully to all the shapes that were presented at systole. “And that overshadows them learning, initially, what’s associated with shock or not shock,” Garfinkel said. “There’s something inherent about the thing that is presented when the heart is beating which is more fearful. And that’s so strong. That’s such a strong effect, it really blew my mind.”

  “The heartbeat signal is shown to have an intrinsic threatening value, which kind of slows down unlearning of threat,” said Hugo Critchley, a psychiatrist at Brighton and Sussex Medical School and another author on the study.

  When the Inner World Rules

  Adaptations to responses other than fear may also have built on this coupling of heartbeat and inhibition. In a paper published in Cognition in March, researchers found that eye movements occur more often at systole, while we fix our gaze on a target more often during diastole. During rapid eye movements, the brain momentarily blinds us so that we don’t see our surroundings jump. We seem to time that sampling of the visual environment to coincide with moments of inner quiescence.

  “Systole is the point when you’re least sensitive to the world, when processing tends to be dampened down — when the inner world rules,” said Garfinkel, who was not involved in the study. “So it makes sense to couple your eye movements and be blind when you don’t mind as much about the outside world.”

  Critchley, Garfinkel and others have also found that systole is more likely to enhance fear processing in people with anxiety. The researchers now hope that their work can guide therapies for certain phobias and post-traumatic stress disorder. “If you can change how threatening stimuli are” by presenting them at different phases of the cardiac cycle, Critchley said, “then you can get people out of anxiety states in one form or another.”

  Other scientists are studying how information sampling and sensory processing, as well as behavior, might be adaptively coupled to other physiological rhythms, such as breathing and digestion. What’s readily apparent in that work, too, is that “the world isn’t just a stable thing,” Garfinkel said. “How we perceive it is based on our own bodies.”

• VE3CLQ IARU HF Championship
  

  Coming up this weekend, July 11 - 12, is the IARU HF World Championship.  The contest runs from 1200 UTC Saturday and ends at 1159 UTC on Sunday.

  
  

  Rules for this contest can be found HERE, and I would suggest you read them before you start the contest.

  
  

  Always lots of good DX available during this event, let's hope the propagation picks up before Saturday.