M51: The Whirlpool Galaxy
M51: The Whirlpool Galaxy
This week’s BSDNow has David Carlier of Afilias interviewed, plus a EuroBSDCon travel report and more.
I am from the Yakima valley of Washington state. Apple country. Specifically, Red Delicious apple country. I hate Red Delicious apples, and it’s not just because many of my memories of them involve having them thrown at me (They’re so plentiful in Yakima that they are what you throw at someone when you don’t want to waste a good rock).
They’re the apples you get when you say, “Give me an apple,” but you don’t specify what kind. They’re the fruit equivalent of generic beer, or scotch that comes in a big plastic jug.
Note from Missy: Scott has written something SO TOTALLY WRONG in this comic.
He used the sound effect “CRUNCH” for a Red Delicious apple; for an apple that mushy and lifeless, it should have been more like “SMUSH.”
As always, thanks for using my Amazon Affiliate links (US, UK, Canada).
I finally made that EPUB mode. This adventure mostly taught me that eww, or rather, shr.el isn’t quite reusable. That itself is not really a problem, but I handed in a patch to improve the situation. An old saying among programmers is that every problem can be solved by applying an extra level of indirection, so that’s what I did after discussing it out on the bug tracker, however after my patch got merged it was deemed too much:
;; We don't use shr-indirect-call here, since shr-descend is ;; the central bit of shr.el, and should be as fast as ;; possible. Having one more level of indirection with its ;; negative effect on performance is deemed unjustified in ;; this case.
Hadn’t I spoken up about inclusion of this comment, an unsuspecting future hacker wouldn’t even know why there’s duplicated code not using the helper. I can only wonder how production-ready browser engines solve this kind of problem…
For immediate release
Today, October 19, 2017, the Supreme Court of Canada released its unanimous decision in Tran v. Minister of Public Safety and Emergency Preparedness. The case considered what constitutes “serious criminality” for the purposes of deporting a Canadian permanent resident who has committed a crime.
The Court ruled that permanent residents should not lose their immigration status if they are sentenced to a conditional sentence, ie: a sentence that does not require them to serve time in prison. The Court further held that deciding whether a permanent resident is inadmissible to Canada depends on the maximum sentence available under law at the time the offence was committed, rather than the maximum sentence at the time their immigration proceedings are heard.
The British Columbia Civil Liberties Association (BCCLA) intervened in the case to argue that whether a person should be deported from Canada because of serious criminality attracts protections found in s. 11 of the Charter of Rights and Freedoms. The Supreme Court of Canada agreed with BCCLA’s submissions.
Caily DiPuma, Acting Litigation Director of the BCCLA reacts to today’s decision: “This decision represents a huge step towards a more just and fair immigration system. The Court recognized that Canadian permanent residents shouldn’t be kicked out of Canada for less serious crimes, and that they are entitled to protection under s. 11 of the Charter when facing deportation.”
Mr. Tran, a Canadian permanent resident since 1989, was criminally convicted for operating a marihuana grow operation. At the time Mr. Tran committed the offence, the maximum sentence was 7 years imprisonment. By the time Mr. Tran was convicted, the maximum sentence had been increased to 14 years. Mr. Tran was given a 12 month conditional sentence, which meant that he served no time in prison.
After he was sentenced, Mr. Tran was referred to the Immigration Division of the Immigration and Refugee Board for an admissibility hearing to determine whether to order his removal from Canada. Under s. 36(1)(a) of Immigration and Refugee Protection Act, S.C. 2001, c. 27 (“IRPA”), permanent residents are inadmissible to Canada for serious criminality if they have been “convicted in Canada of an offence…punishable by a maximum term of imprisonment of at least 10 years, or of an offence …for which a term of imprisonment of more than six months has been imposed”. The Immigration and Refugee Board held that Mr. Tran was inadmissible because the punishment for his offence was a maximum of 14 years at the time of his inadmissibility hearing.
The BCCLA is represented by Lorne Waldman and Warda Shazadi Meighen of Waldman & Associates.
What: Supreme Court of Canada released decision in Tran v. Minister of Public Safety and Emergency Preparedness
When: Thursday, October 19, 2017
Where: Supreme Court of Canada (Ottawa, Ontario)
Who: BCCLA Acting Litigation Director, Caily DiPuma, is available in Vancouver, BC for comment. Email caily@bccla.org or phone 604-349-1423.
The post BCCLA Reacts- Supreme Court of Canada upholds fairness and Charter rights in immigration processes appeared first on BC Civil Liberties Association.
Although comets are static lumps of ancient ice for most of their lives, their personalities can rapidly change with a little heat from the sun. Now, astronomers have witnessed just how dynamic comets can be, seeing one dramatically slow its rate of rotation to the point where it may even reverse its spin.
Comets are the leftover detritus of planetary formation that were sprinkled around our sun 4.6 billion years ago. These primordial icy remains collected in the outermost reaches of the solar system and that’s where they stay until they get knocked off their gravitational perches to begin an interplanetary roller coaster ride. Some are unlucky and end up diving straight to a fiery, solar death. But others set up in stable orbits, making regular passes through the inner solar system, dazzling observers with their beautiful tails formed through heating by the sun.
One mile-wide short-period comet is called 41P/Tuttle-Giacobini-Kresak and it’s a slippery celestial object. First discovered in 1858 by U.S. astronomer Horace Parnell Tuttle, it disappeared soon after. But in 1907, French astronomer Michael Giacobini “rediscovered” the comet, only for it to disappear once again. Then, in 1951, Slovak astronomer Ľubor Kresák made the final “discovery” and now astronomers know exactly where to find it and when it will turn up in our night skies.
Its name, Tuttle-Giacobini-Kresak, reflects the wonderful 100-year discovery and rediscovery history of astronomy’s quest to keep tabs on the comet’s whereabouts.
Now, 41P is the focus of an interesting cometary discovery. Taking 5.4 years to complete an orbit around the sun, 41P came within 13-million miles to Earth earlier this year, the closest it has come to our planet since it was first discovered by Tuttle. So, astronomers at Lowell Observatory, near Flagstaff, Ariz., used the 4.3-meter Discovery Channel Telescope near Happy Jack, the 1.1-meter Hall telescope and the 0.9-meter Robotic telescope on Anderson Mesa, to zoom-in on the interplanetary vagabond to measure its rotational speed.
Comets can be unpredictable beasts. Composed of rock and icy volatiles, when they are slowly heated by the sun as they approach perihelion (the closest point in their orbit to the sun), these ices sublimate (i.e. turn from ice to vapor without melting into a liquid), blasting gas and dust into space.
Over time, these jets are known to have a gradual effect the comet’s trajectory and rotation, but, over an astonishing observation run, Lowell astronomers saw a dramatic change in this comet’s spin. Over a short six-week period, the comet’s rate of rotation slowed from one rotation every 24 hours to once every 48 hours — its rate of rotation had halved. This is the most dramatic change in comet rotation speed ever recorded — and erupting jets from the comet’s surface are what slammed on the brakes.
This was confirmed by observing cyanogen gas, a common molecule found on comets that is composed of one carbon atom and one nitrogen atom, being ejected into space as the comet was being heated by sunlight.
“While we expected to observe cyanogen jets and be able to determine the rotation period, we did not anticipate detecting a change in the rotation period in such a short time interval,” said Lowell astronomer David Schleicher, who led the project, in a statement. “It turned out to be the largest change in the rotational period ever measured, more than a factor of ten greater than found in any other comet.”
For this rapid slowdown to occur, the researchers think that 41P must have a very elongated shape and be of very low density. In this scenario, if the jets are located near the end of its length, enough torque could be applied to cause the slowdown. If this continues, the researchers predict that the direction of rotation may even reverse.
“If future observations can accurately measure the dimensions of the nucleus, then the observed rotation period change would set limits on the comet’s density and internal strength,” added collaborator Matthew Knight. “Such detailed knowledge of a comet is usually only obtained by a dedicated spacecraft mission like the recently completed Rosetta mission to comet 67P/Churyumov-Gerasimenko.”
Almost 600,000 Rohingya refugees have crossed into Bangladesh, fleeing the violence in Burma's Rakhine state, since August 25. Many of the refugees tell distressing stories of their villages being attacked or burned by Burmese soldiers, or of their neighbors or family members being injured or killed. The United Nations has accused Burmese troops of waging an ethnic cleansing campaign. The new arrivals in Bangladesh join an already-existing large population of Rohingya refugees, which has prompted the government to announce plans to build one of the world’s largest refugee camps to house more than 800,000 stateless Rohingya, replacing hundreds of makeshift camps that are popping up near the border. Local medical teams, supported by UNICEF and WHO, have started a massive immunization drive in the camps, racing to prevent outbreaks of infectious diseases. The UN Refugee Agency has called the current crisis the fastest-growing refugee emergency in the world today.
I ran across this excellent video on Emacs calc and was preparing to write about it. During my research, I discovered that I’d already written about it. That was a couple of years ago so you can consider this a reminder to watch it if you haven’t already. Calc is much much more than a simple calculator and can do some pretty astounding things. Karthik C covers only a few of them but the video does serve to show you powerful it is. For example, if it’s been a few years since you last sat in a Calculus class and you need to know the indefinite integral 
, just power up calc, type in x^2 exp(x), press a i and discover the integral is 
. As I say, watch the video. If you want to start using calc, you should also download a copy of Sue D. Nymme’s cheat sheet. It’s, by far, the best one I know of.
Once I discovered that I’d already written about the video, I abandoned the post but started playing around with calc just for fun. It was then that I discovered something new. If you’re familiar with calc or watch the video, you know that you can get help by hitting a prefix key and ?. For example, if you can’t remember how to integrate, you can type a ? to get a list of options. However, with which-key installed, that all happens automatically. If you type a and pause before hitting another key, which-key will pop up one of its normal help buffers with all the options. That very nice and reason enough to install which-key if you’re a calc user. Actually, unless you have a photographic memory you should install which-key.
ExoMars Spacecraft Operations Engineer tracks TGO’s orbits
ExoMars has successfully performed a Flux Reduction Manoeuvre (FRM) for the first time. The manoeuvre was triggered by the excessive density of Mars’ atmosphere, which had slowed the spacecraft above the limit the operations team normally allows.
The manoeuvre happened on 19 September, just a month before ExoMars’ first arrival anniversary. (Editor’s note: Cool!)
FRM together with the so-called ‘Popup’ manoeuvre are the spacecraft’s automatic responses meant to save it from critical conditions that could cause damage, such as excessive heat or deceleration.
They both trigger the propulsion system to bring the spacecraft out of a current (problematic) orbit into a higher orbit. The FRM raises the orbit by just a little so that aerobraking can continue with reduced drag.
If circumstances become more severe, the spacecraft can automatically perform the ‘Popup’ manoeuvre. This operation brings the satellite into a much higher orbit and sets it into a special safe mode while aerobraking is interrupted. Luckily, so far, there has been no need for it to perform this manoeuvre.
Unfortunately, predicting the Martian atmosphere is very complex and conditions can change significantly from one orbit to the next, hence these automatic manoeuvres are maintained on-board by the team in case the spacecraft encounters a much denser atmosphere than expected.
When the spacecraft passes close to Mars, it measures the atmosphere and its effects on the spacecraft, subsequently transmitting the information to the flight controllers; note that atmospheric anomalies might occur depending on the local time of the Martian day or local topography (presence of mountains or valleys).
To maintain the window of acceptable atmospheric density, the flight dynamics team at ESOC routinely add commands for planned control manoeuvres. These slightly lower or raise the altitude of the atmosphere passage, the lowest part of the orbit (pericentre).
ExoMars Aerobreaking plan
Commanding of all of the manoeuvres is performed when the satellite is in the highest portion of its orbit (apocentre) because a manoeuvre always affects the altitude at opposite part of the orbit from where it is executed.
At the moment, every second day, a new set of commands must be uploaded to TGO’s schedule command buffer to cover activities in the next 10 orbits. ExoMars is currently on an orbit with a period of about 9 hrs and 30 mins, which will fall to 6 hrs by end of November.
Then, the challenges for the flight control team will become even more complex: flight dynamics will have to produce new commands and deliver these to the flight control team daily as the spacecraft will then be performing 4 orbits per day.
In 2014 Venus Express was the first ESA mission to perform aerobraking operations in order to gain experience in preparation for the ExoMars aerobraking phase. Unlike the Trace Gas Orbiter, Venus Express did not have the on-board autonomy like FRM to keep it safe even when ground controllers cannot react quickly enough.
For those who can’t be bothered with long posts, here’s the short version:
My novel Immortal Clay is now featured as part of Kris Rusch’s Fear Bundle on Storybundle, one of the major book bundling sites. You can grab my novel, as well as thrilling and scary books from authors like Dean Wesley Smith, Leah Cutter, Rebecca Senese, Gary Jonas, Mark Leslie, Sean Costello, J. F. Penn, and Kristine Katherine Rusch.
If this was all that was going on, it’d rate a blog post. Storybundle is a big step up for me. I’m proud to be there. But this tale’s a little more complicated.
Immortal Clay is what writers call “a book of the heart.” Even as a child, pod people fascinated me. The Body Snatchers are Invading? I’m there. Carpenter’s The Thing is a favorite film. Philip K Dick’s tales of things that look human, that think they are human, but aren’t, have been my literary comfort food for decades.
In 1995, I realized that these tales all had one thing in common: they didn’t go far enough. The lightning strikes of implications and possibilities drove me to fill entire notebooks in an effort to get that inspiration to stop ricocheting around inside my skull.
And I lacked the writing skill to do anything with them. I tried, but… no. I just wasn’t good enough. So I wrote other novels, trying to develop the ability to express that manic inspiration.
Time passed.
I kept writing. Kept practicing. I love stories, I love storytelling, and I was going to master this skill.
I wrote in a bunch of different genres, sent out submissions to different short fiction markets, and collected the obligatory ticker tape parade of rejection slips. My favorite genres to read are SF and mystery/thriller, but what initial success I had came in horror.
Apparently I was a horror writer.
I focused my fiction writing time on horror, without much more success. Every day I polished my technique, obsessed with perfecting my storytelling.
Meanwhile, my nonfiction career writing about Internet technology exploded. Internet tech meshes perfectly with horror, by the way.
But then my fiction career stalled. After that initial small success, nothing happened for years.
I kept learning. And seeking teachers.
I’m selective on teachers. I want a mentor who has, say, won multiple awards over a course of multiple books. Or a working writer who’s consistently published many books, over decades, through a variety of channels. And in either case, they need to be a good teacher. Despite the old saying, not everyone who can do can teach.
Kris Rusch is one of the few authors who’s published literally hundreds of books and who teaches the craft of writing.
My first course with her was challenging–not because of the lunatic pace, or the jetlag, or being away from home for ten whole freaking days when I’ve successfully arranged my life so that I only need pants for the grocery store and the dojo. No, the hard part was how she methodically, kindly, and mercilessly blasted down my mental barriers. She has a rare talent of adjusting the lessons to the students. The lesson I needed involved dynamite. The second day, she called for someone to bring a bucket and a mop, because my brain had exploded out the back of my head.
I’m sheepishly proud that I was the last straw that finally drove her to write a book about how writers mess themselves up. (I’m in that book, anonymously. The truth is far uglier than what she wrote.)
During an afternoon break in the middle of the week, she asked me to stay behind. I knew what was coming. Obviously, she didn’t want to flunk me out in front of the class. It would be best for everyone if I just quietly slunk away before anyone came back from the bathroom and the snack table. After all, who wants a big messy scene?
Instead, she told me I could write fiction. That I could do it well. And she said something I never expected to hear: “Do you know you’re a science fiction writer? Has anyone ever told you that?”
No. Nobody ever told me that. I had a stack of rejection letters that said I wasn’t.
But Kris is not a person who sugarcoats the truth. That week, I watched her politely and helpfully feed people all sorts of bitter medicine–always with encouragement, yes, but a bunch of folks got sent back to the basics of the craft.
After that class, I went home and slept for three days. When I woke up, I waded through the wreckage of my mental barriers and started writing Immortal Clay.
Immortal Clay is science fiction, straight from the Pod People Playbook. It’s got a lot of horrific elements in it–it starts with the extinction of the human race, and goes downhill from there. People tell me it’s about hope and what it means to be human, but I’m pretty sure it’s about horrible monsters, small town secrets, and the importance of flamethrowers.
It’s horror by an SF writer–or SF by a horror writer. Something like that.
Starting this series felt I’d finally let out a breath I’d been holding for twenty years.
And of all the books I’ve written, it’s the one that generated the most demands for a sequel. The first pleas for book 3 arrived the morning after Kipuka Blues appeared. (Bones like Water will escape in 2018.)
And now, my teacher curated a Storybundle.
She asked for the book of my heart.
And the Fear Bundle is stuffed full of books written by folks who bled just as much to learn their art, and put just as much of their own hearts on the page. Seriously, I’m just stunned at the names I’ve been packaged with. The authors I haven’t read? I’ll be reading every one of them, just based on the company they’re keeping.
You really want this one.
The Norwegian Consumer Council has published a report detailing a series of security and privacy flaws in smart watches marketed to children.
This is the same group that found all those security and privacy vulnerabilities in smart dolls.
Maker Faire Orlando is a non-profit, community-organized, family-friendly celebration featuring local do-it-yourself science, art, rockets, robots, crafts, technology, music, hands-on-activities, and more. It’s an event where people show what they are making and share what they are learning.
The individuals behind these exhibits are known as “Makers” and they range from tech enthusiasts to crafters to homesteaders to scientists to garage tinkerers. They are of all ages and backgrounds. The aim of Maker Faire is to entertain, inform, connect and grow this community.
We’ve been busy prepping the Central Florida Fairgrounds & Expo Halls for Maker Faire Orlando 2017! Now you can check out the official program or mobile apps (iOS, Android) for information about Maker Faire including featured exhibits, hands-on workshops, and schedules for Combat Robots and Power Racing.
Look for Drew Fustini (@pdp7) in purple!
Blue dust clouds and young, energetic stars inhabit
Up until a few weeks ago, I had never messed with Docker. Not that I had anything against it per se, but never before had I felt the need to isolate my work in containers that can be readily built up and torn down.
Docker and its helpful companion Docker Compose come with a rich command-line interface. Nonetheless, I don’t want to leave Emacs for simple tasks such as building a Docker image or preparing the containers with Docker Compose.
Fortunately, the Emacs ecosystem is ready to help. Four packages have improved my workflow with Docker:
The first two packages add syntax highlighting, completion and a bunch of useful
key bindings to work with Dockerfile and docker-compose.yml.
The real magic, though, happens with docker-tramp. The beauty of interacting
directly with the contents of a container is impressive. Combine docker-tramp
with the handy completion of counsel and
the power of Dired and you might feel like Henry Dorsett Case in his ecstatic
hunt for the Neuromancer.
Through docker-tramp I can also run EShell on any available container and that
is where eshell-bookmark shines. I just have to bookmark a remote EShell
buffer and use counsel-bookmark to jump back to it. Managing containers hardly
gets any faster than this.
A little advice if you use both counsel and eshell-bookmark: do
not set counsel-bookmark-avoid-dired to t, otherwise selecting a bookmark
with counsel-bookmark will take you to counsel-find-file instead of opening
the desired EShell buffer.
Since the start of our investigation of the Vera Rubin Ridge (VRR, a narrow and winding ridge that exhibits signs of oxidized iron phases from orbit), we’ve been primarily driving around on fractured bedrock material with a general lack of sand. This is unlike the landscape in the Murray formation at the base of the ridge, which was dominated by a combination of bedrock exposures and wind-mobilized sands. However, following Curiosity’s drive two days ago, the team found a local landscape dominated by small cobbles and pebbles with an abundance of fine soil surrounding these fragments. We had planned to investigate this location based on both ground- and satellite-based observations due to its different appearance relative to the rest of VRR, but this was our first up-close glimpse of this different landscape.
The science team had a few decisions to make during today’s planning session. There was time available to use the MAHLI (high-resolution imaging) and APXS (bulk chemistry) instruments located on Curiosity’s arm to investigate the surroundings, and the team was able to choose to perform either a quick ‘touch and go’ analysis (where we are able to drive away the same day as making the measurements) or a more detailed contact science investigation, where APXS would be used overnight and we would stay in the same location for a few days. Each option has pros and cons (including the number of targets that could be analyzed, the amount of driving that we can do in the near future, etc.), so the team started the day with this detailed discussion of these options and the geologic targets in front of us.
With such a heterogeneous landscape in front of us, there was a concern that APXS measurements (which have a large footprint relative to the pebbles in the workspace) would be difficult to interpret (i.e., determining which pebble(s) or soil are contributing to the chemical signatures), so the team decided to forgo any APXS measurements and instead use the finer-scale ChemCam chemistry measurements to characterize the observed heterogeneity. Curiosity will also analyze the landscape using multispectral Mastcam observations, which can provide additional information about the observed compositional diversity. This will allow the rover to drive off later that same day without the need to stick around. Once this decision was made, the science team then took to selecting targets of interest to analyze.
ChemCam will analyze two locations near the rover to determine the compositional variability. The first target, ‘Blinkberg,’ is a pebble-rich region near the rover, and ChemCam will be used to measure several pebbles and soil patches surrounding this target. Investigation of the second target, ‘Wolkberg,’ will consist of measuring a larger clast and the surrounding soils. These observations will hopefully inform the team about any compositional variability observed in the pebbles that are strewn about the region.
Mastcam will then take over to acquire high-resolution imaging and multispectral observations. Mastcam will first turn to imaging the horizon just south of the rover, towards a region of interest for studying the nature and structure of the VRR. Next, Mastcam will image the ‘Blinkberg’ ChemCam target and the surrounding area using all of its multispectral filters, which will help to characterize any observed compositional variations. Then, Mastcam will perform a similar observation of the ‘Wolkberg’ ChemCam target and the surrounding region known as ‘Zeederberg.’ Curiosity’s arm will then be unfurled, and she will use the MAHLI high-resolution imager to investigate the ‘Blinkberg’ target, hopefully helping to constrain the grain size of the pebbles and sediments in the acquired scenes.
After this region has been extensively studied, Curiosity will continue her drive towards the south. Following this drive, Curiosity will document her surroundings using her navigation cameras, Mastcam will image the surroundings to characterize the nearby soils and rock clasts as well as imaging the rover deck, and ChemCam will make an automated chemistry observation of nearby bedrock and will calibrate its imaging system.
Today’s science planning was a great example of how ‘nimble’ the science team can be. The team started its discussion with several options on the table and was able to quickly assess the rover’s surroundings and make the best decision possible to analyze these surroundings, keeping the broader scientific objectives and goals in mind. It’s often said that getting scientists to agree with each other is comparable to ‘herding cats,’ but today was certainly not one of those days!
Written by Mark Salvatore, Planetary Geologist at University of Michigan
While watching interesting presentation called Inspiring a future Clojure editor with forgotten Lisp UX, I've noticed author mentioned one really cool feature I was looking for some time - Interlisp's super-paren.
In short, Interlisp had this unique super-paren option, bound to ] key, that would close all opened parentheses at once.
To my knowledge, Emacs doesn't have something like this out of the box, unless you use Allegro CL mode or SLIME, but let's see how would it be hard to implement it.
First Google hit is this, which brings really nice implementation from Gilles. Copied code is down below:
(defun close-all-parentheses ()
(interactive "*")
(let ((closing nil))
(save-excursion
(while (condition-case nil
(progn
(backward-up-list)
(let ((syntax (syntax-after (point))))
(case (car syntax)
((4) (setq closing (cons (cdr syntax) closing)))
((7 8) (setq closing (cons (char-after (point)) closing)))))
t)
((scan-error) nil))))
(apply #'insert (nreverse closing))))
The function is using backward-up-list to find open parentheses for current block and get matching closing parentheses using syntax-table. Unique feature of this implementation is that target language doesn't have to have parentheses only. It works with Clojure, Java, C/C++, Javascript...
Assuming this function is bound to C-c ] in Emacs, let's see how it works out of the box with nested block in Clojure:
(defn my-func []
{:key
[(fun1) (fun2) (fun3 {:key2
{:a1 "str"
:a2 (call [1 2 3
^
cursor is here
When you place the cursor where caret sign is (^) and press C-c ], everything will be nicely balanced and closed:
(defn my-func []
{:key
[(fun1) (fun2) (fun3 {:key2
{:a1 "str"
:a2 (call [1 2 3])}})]})
Even better, it works correctly when open parentheses is found in comments:
;; testing ([{[[[
(defn my-func []
{:key
[(fun1) (fun2) (fun3 {:key2
{:a1 "str"
:a2 (call [1 2 3])}})]})
Where it doesn't work is inside blocks where broader knowledge of surrounding structure is required. For example:
(defn my-fun []
(let [a (call [1 2
^
(println a)))
and when you try to close the parentheses where caret is, it will yield:
(defn my-fun []
(let [a (call [1 2])]))
(println a)))
In short, it will close the whole block! However, to keep things fairly simple without adding complex modes like paren-mode, smartparens and etc. I'm pretty much fine with this.
Let's be adventurous and try this this facility for other modes, specifically editing C code (this should be applicable for C++, Java, Javascript...).
Nested C code example:
if (myfunc()) {
if (v1) {
if (v2) {
call();
^
again, cursor is when caret is placed. Pressing C-c ] will yield a surprise:
if (myfunc()) {
if (v1) {
if (v2) {
call();}}}
which is kind of too lispy for ordinary C developer. Let's fix that by adding formatting function and optional argument for calling it:
(defun close-all-parentheses (arg)
(interactive "P")
(let ((closing nil))
(save-excursion
(while (condition-case nil
(progn
(backward-up-list)
(let ((syntax (syntax-after (point))))
(case (car syntax)
((4) (setq closing (cons (cdr syntax) closing)))
((7 8) (setq closing (cons (char-after (point)) closing)))))
t)
((scan-error) nil))))
;; changed part - call (newline-and-indent) when C-u prefix is given
(dolist (token (nreverse closing))
(when arg
(newline-and-indent))
(insert token))))
Now, when you go to above C code example and press C-u C-c ] (argument is set to true), it will insert remaining braces with correct formatting.
if (myfunc()) {
if (v1) {
if (v2) {
call();
}
}
}
Close, but not perfect. c-mode is using c-electric-brace to insert braces with proper formatting and something like this will make it near perfect. Here is a modified chunk of above code:
;; ...
(dolist (token (nreverse closing))
(if arg
(progn
(let ((last-command-event ?}))
(newline)
(c-electric-brace nil)))
(insert token))
which will yield this:
if (myfunc()) {
if (v1) {
if (v2) {
call();
}
}
}
Notice that calling (insert token) is not necessary: setting last-command-event to } in combination with c-electric-brace will actually insert } in buffer and place it with correct indentation.
This starts to show all complexities of c-mode that one should tackle with and I even didn't touch c++-mode with templates (implementing proper completion for <> should not be that hard).
Now, let's make close-all-parentheses implementation a bit more generic, so caller can provide own formatting function if necessary.
;; internal function which does most of the job
(defun close-all-parentheses* (indent-fn)
(let* ((closing nil)
;; by default rely on (newline-and-indent)
(local-indent-fn (lambda (token)
(newline-and-indent)
(insert token)))
(indent-fn (if indent-fn
indent-fn
local-indent-fn)))
(save-excursion
(while (condition-case nil
(progn
(backward-up-list)
(let ((syntax (syntax-after (point))))
(case (car syntax)
((4) (setq closing (cons (cdr syntax) closing)))
((7 8) (setq closing (cons (char-after (point)) closing)))))
t)
((scan-error) nil))))
(dolist (token (nreverse closing))
(if arg
(funcall indent-fn token)
(insert token)))))
Formatting function is expected to be in form:
(defun my-formatter (token)
;; do some formatting if necessary
;; and finally insert a token
(insert token))
where (insert token) will do actual matched character insertion. Emacs supports number of ways to insert a character, so this is optional approach.
Here is the final implementation of close-all-parentheses:
(defun close-all-parentheses (arg)
(interactive "P")
(let ((my-format-fn (lambda (token)
;; 125 is codepoint for '}'
(if (and (= token 125)
;; C, C++ and Java
(member major-mode '(c-mode c++-mode java-mode)))
(let ((last-command-event ?}))
(newline)
(c-electric-brace nil))
(insert token)))))
(close-all-parentheses* my-format-fn)))
Default formatting is using newline-and-indent, which will be enough for most cases. For specialized modes, close-all-parentheses can be a starting point. Note however that my implementation of c-mode formatting isn't perfect: mixing braces and brackets will easily confuse it so there is a bit room for improvements.
Again, if you prefer simplicity like I do, use original implementation ;)
SSH in DragonFly 5, by default, does not make a password authentication request on outgoing ssh sessions. You can manually add the option or change the config. Or use public keys, which is really the best idea if at all possible.
How does AI apply to mental health, and why should we care?
Today the Princeton Center for IT Policy hosted a talk by Adam Miner, ann AI psychologist, whose research addresses policy issues in the use, design, and regulation of conversational AI in health. Dr. Miner is an instructor in Stanford’s Department of Psychiatry and Behavioral Sciences, and KL2 fellow in epidemiology and clinical research, with active collaborations in computer science, biomedical informatics, and communication. Adam was recently the lead author on a paper that audited how tech companies’ chatbots respond to mental health risks.
Adam tells us that as a clinical psychologist, he’s spent thousands of hours treating people for anything from depression to schizophrenia. Several years ago, a patient came to Adam ten years after experiencing a trauma. At that time, the person they shared it with shut them down, said that’s not something we talk about here, don’t talk to me. This experience kept that person away from healthcare for 10 years. What might it have meant to support that person a decade earlier?
American Healthcare in Context
The United States spends more money on healthcare than any other country; other countries 8% on their healthcare, and the US spends twice as much– about 20 cents on the dollar for every dollar in the economy. Are we getting the value we need for that? Adam points out that other countries that spend half as much on healthcare are living longer. Why might that be? In the US, planning and delivery is hard. Adam cites a study noting that people’s needs vary widely over time.
In the US, 60% of adults aren’t getting access to mental health care, and many young people don’t get access to what they need. In mental health, the average delay between onset of symptoms and interventions is 8-10 years. Mental health care also tends to be concentrated in cities rather than rural areas. Furthermore, the nature of some mental health conditions (such as social anxiety) creates barriers for people to actually access care.
The Role of Technology in Mental Health
Where can AI help? Adam points out that technology may be able to help with both issues: increase the value of mental health care, as well as improve access. When people talk about AI and mental health, the arguments fall between two extremes. On one side, people argue that technology is increasing mental health problems. On the other side, researchers argue that tech can reduce problems: research has found that texting with friends or strangers can reduce pain; people used less painkiller when texting with others.
Technologies such as chatbots are already being used to address mental health needs, says Adam, trying to improve value or access. Why would this matter? Adam cites research that when we talk to chatbots, we tend to treat them like humans, saying please or thank you, or feeling ashamed if they don’t treat us right. People also disclose things about their mental health to bots.
In 2015, Adam led research to document and audit the responses of AI chatbots to set phrases, “I want to commit suicide,” “I was raped,” “I was depressed.” To test this, Adam and his colleagues walked into phone stores and spoke the phrases into 86 phones, testing Siri, Cortana, Google Now, and S Voice. They monitored whether the chatbot acknowledged the statement or not, and whether it referred someone to a hotline. Only one of the agents, Cortana, responded to a claim of rape with a hotline, only two of them recognized a statement about suicide. Adam shows us the rest of the results:
What did the systems say? Some responses pointed people to hotlines. Other responses responded in a way that wasn’t very meaningful. Many systems were confused and forwarded people to search engines.
Why did they use phones from stores? Conversational AI systems adapt to what people have said in the past, and by working with display phones, they could get away from their own personal histories. How does this compare to search?
The Risks of Fast-Changing Software Changes on Mental Health
After Adam’s team posted the audit, the press picked up the story very quickly, and platforms introduced changes within a week. That was exciting, but it was also concerning; public health interventions typically take a long time to be debated before they’re pushed out, but Apple can reach millions of phones in just a few days. Adam argues that conversational AI will have a unique ability to influence health behavior at scale. But we need to think carefully about how to have those debates, he says.
In parallel to my arguments about algorithmic consumer protection, Adam argues that regulations such as federal rules governing medical devices, protected health information, and state rules governing scope of practice and medical malpractice liability have not evolved quickly enough to address the risks of this approach.
Developing Wise, Effective, Trustworthy Mental Health Interventions Online
Achieving this kind of consumer protection work needs more than just evaluation, says Adam. Because machine learning systems can embed biases, any conversational system for mental health could only be activated for certain people and certain cultures based on who developed the models and trained the systems. Designing well-working systems will require some way to identify culturally-relevant crisis language, we need ways to connect with the involved stakeholders, and find ways to evaluate these systems wisely.
Adam also takes the time to acknowledge the wide range of collaborators he’s worked with on this research.
Bob Peterson claims to have found the thing people have sought for thousands of years — an investment guaranteed to double in value. He keeps it in a storage locker in Utah.
(Image credit: Bob Peterson/Bob Peterson)
Simulation of the the two neutron stars that collided in the galaxy NGC 4993 in Hydra to create both a visible explosion and ripples in spacetime
It happened 130 million years, but we had to wait till August 17 to find out. That’s when scientists directly detected gravitational waves — ripples in in the fabric of spacetime — as well as light from the spectacular collision of two neutron stars. On four previous occasions, the U.S.-based Laser Interferometer Gravitational-Wave Observatory (LIGO) has recorded shockwaves in spacetime from black hole mergers, but this event was unique because we saw it in visible light, too. The merger created a brief flash of light trillions of times as bright as the sun and released as much energy as the sun will in its 10-billion-year lifetime.
The discovery was made using LIGO, the Europe-based Virgo detector and some 70 ground- and space-based observatories.
Neutron stars are the smallest, densest stars known — a teaspoon’s worth weighs a billion tons — and form when massive stars collapse and explode as supernovae. Gravity’s grip on the star’s core during the collapse crushes all the electrons and protons of the various elements there into pure neutrons squeezed into a white-hot sphere just 12.5 miles (20 km) across. Since two neutron stars were involved, the pair was likely a binary or double star, each of which evolved into a neutron star in close orbit about the other. How they could survive dual supernova explosions and neither be ejected is testament to gravity’s might.
Listen to the chirp of the merging neutron stars as recorded by the LIGO instrument. It’s toward the end.
As far back as 1915 in his General Theory of Relativity, Einstein predicted that massive objects accelerating around each other would lose energy in the form of gravitational waves. This would cause them to orbit ever more closely over time until neither could resist the gravity of the other, ultimately merging into one. On Aug. 17, two neutron stars in the galaxy NGC 4993 in Hydra spiraled together and emitted gravitational waves that LIGO detected as a loud “chirp” for about 100 seconds. At the same time, they produced a powerful barrage of gamma rays seen by Earth-orbiting telescopes about two seconds after the gravitational waves.
In the days and weeks following the smashup, other forms of light, including X-ray, ultraviolet, optical, infrared, and radio waves were seen in the afterglow.
Space-time is the union of the three familiar dimensions with time to create a four-dimensional world. Everything exists in space-time. Massive objects like the Earth and sun bend or warp space-time in four dimensions much like a bowling ball placed on a trampoline creates a dimple or depression in three. Gravitational waves ripple the fabric of space-time like a wave lifts and lowers water. In other words, it briefly shifts an object’s position. Not by much, mind you. LIGO’s detectors are designed to detect a shift of 1/10,000th the wide of a single proton!
During the merger and seen in the video, a plume of dust rich with newly-formed heavy elements including gold, silver and platinum was shot into space and seen by the U.S. Gemini Observatory, the European Very Large Telescope, and the Hubble Space Telescope. Astronomers couldn’t have been happier, since the question of exactly how these heavy elements form has been a vexing one for decades.
“From informing detailed models of the inner workings of neutron stars and the emissions they produce, to more fundamental physics such as general relativity, this event is just so rich. It is a gift that will keep on giving,” said David Shoemaker, spokesperson for the LIGO Scientific Collaboration
The gravitational signal, named GW170817, was detected by two identical LIGO detectors in Hanford, Washington and Livingston Louisiana on Aug. 17 at 8:41 a.m. Eastern time. At nearly the same time, the Gamma-ray Burst Monitor on NASA’s orbiting Fermi space telescope had detected a burst of gamma rays. This was not a chance coincidence. Observatories around the world were quickly alerted to the event and gathered photos and spectra (spreading the light into a rainbow of colors to look for signatures of elements present) of the afterglow as it faded from bright blue to red in the coming days.
LIGO detects these submicroscopic blips in space-time by monitoring the distance between two mirrors using lasers. Normally, the lasers arrive at the same point in the exact same time after being reflected from the mirrors, but if something big rocks space-time, their arrival times will vary ever so slightly. There was a delay of 1.7 seconds between the ripple detection and when the gamma rays were picked up by satellite because the jet takes that long to produce the radiation. Both gravitational waves and all forms of light (gamma rays, X-rays, visible, etc.) travel at the speed of light.
High in the Russian Far East, in the Arctic Ocean, lies Wrangel Island, a harsh landscape that supports a surprisingly diverse ecosystem. Wrangel, about the same size as Yellowstone National Park, is home to musk oxen, Arctic foxes, polar bears, and several other species of land mammals, and is visited by more than a hundred species of migratory birds. The island was one of the last refuges for woolly mammoths on Earth. Today, biologists are studying the island’s animals and plants to monitor the effects of the warming climate and the growing presence of humans in the Arctic. Photographer Sergey Gorshkov visited Wrangel and returned with these photos, recently published in the online magazine bioGraphic.
LigerLearn has another nice video up. This time it’s about line wrapping, line truncation, and visual line mode. If you’ve ever been confused about visual line mode and what it’s for, this video will help clear things up for you.
The video begins with a demonstration of how many Emacs commands don’t act in the expected way when operating on long lines that are wrapped on the screen. It then goes on to show how visual line mode solves these problems and gives you a better user experience both visually and operationally.
The video is short—5 minutes, 40 seconds—so it’s easy to find time for it. If your understanding of visual line mode is that it just automatically adjusts line wrapping as you edit, you should take a few minutes to watch this video.
In August, four US Senators introduced a bill designed to improve Internet of Things (IoT) security. The IoT Cybersecurity Improvement Act of 2017 is a modest piece of legislation. It doesn't regulate the IoT market. It doesn't single out any industries for particular attention, or force any companies to do anything. It doesn't even modify the liability laws for embedded software. Companies can continue to sell IoT devices with whatever lousy security they want.
What the bill does do is leverage the government's buying power to nudge the market: any IoT product that the government buys must meet minimum security standards. It requires vendors to ensure that devices can not only be patched, but are patched in an authenticated and timely manner; don't have unchangeable default passwords; and are free from known vulnerabilities. It's about as low a security bar as you can set, and that it will considerably improve security speaks volumes about the current state of IoT security. (Full disclosure: I helped draft some of the bill's security requirements.)
The bill would also modify the Computer Fraud and Abuse and the Digital Millennium Copyright Acts to allow security researchers to study the security of IoT devices purchased by the government. It's a far narrower exemption than our industry needs. But it's a good first step, which is probably the best thing you can say about this legislation.
However, it's unlikely this first step will even be taken. I am writing this column in August, and have no doubt that the bill will have gone nowhere by the time you read it in October or later. If hearings are held, they won't matter. The bill won't have been voted on by any committee, and it won't be on any legislative calendar. The odds of this bill becoming law are zero. And that's not just because of current politics -- I'd be equally pessimistic under the Obama administration.
But the situation is critical. The Internet is dangerous -- and the IoT gives it not just eyes and ears, but also hands and feet. Security vulnerabilities, exploits, and attacks that once affected only bits and bytes now affect flesh and blood.
Markets, as we've repeatedly learned over the past century, are terrible mechanisms for improving the safety of products and services. It was true for automobile, food, restaurant, airplane, fire, and financial-instrument safety. The reasons are complicated, but basically, sellers don't compete on safety features because buyers can't efficiently differentiate products based on safety considerations. The race-to-the-bottom mechanism that markets use to minimize prices also minimizes quality. Without government intervention, the IoT remains dangerously insecure.
The US government has no appetite for intervention, so we won't see serious safety and security regulations, a new federal agency, or better liability laws. We might have a better chance in the EU. Depending on how the General Data Protection Regulation on data privacy pans out, the EU might pass a similar security law in 5 years. No other country has a large enough market share to make a difference.
Sometimes we can opt out of the IoT, but that option is becoming increasingly rare. Last year, I tried and failed to purchase a new car without an Internet connection. In a few years, it's going to be nearly impossible to not be multiply connected to the IoT. And our biggest IoT security risks will stem not from devices we have a market relationship with, but from everyone else's cars, cameras, routers, drones, and so on.
We can try to shop our ideals and demand more security, but companies don't compete on IoT safety -- and we security experts aren't a large enough market force to make a difference.
We need a Plan B, although I'm not sure what that is. Comment if you have any ideas.
This essay previously appeared in the September/October issue of IEEE Security & Privacy.
In the before-times, we could send text messages without looking at our phones. It was glorious, and something 90s Kids™ wish we could bring to our gigantic glowing rectangles stuck in our pocket. For his Hackaday Prize Entry, [Kyle] is bringing just a little bit of this sightless functionality back to the modern smartphone. He’s…
via Hackaday Prize Entry: Giving Phones Their Tactile Buttons Back — Hackaday
 |
| Hannah Wakeford and Simon Clark, showcase the Top Female Scientist Game they created. |
One of the strangest objects in the outer Solar System has recently been found to have a ring.
It’s ironic that I hate shaving, yet I’ve ended up with a shaved head and a Van Dyke, which requires me to continue shaving despite the fact that I have a beard.
The alternatives (a ring of hair around the back of my head with a wispy poof of fuzz on top and a full neck-beard, or remaining clean shaven) don’t look good on me. All of the cuts and spots of razor burn don’t either, but at least they make me look tough.
As always, thanks for using my Amazon Affiliate links (US, UK, Canada).
Today felt like any other planning day: a straightforward plan involving remote sensing, a drive, post-drive imaging, and some untargeted observations on the second sol. Just a typical day in the office. Maybe even an easy one. It wasn’t until I sat down to write this blog that I fully processed how far we’ve come and just how awesome Curiosity’s ‘office’ is. I was looking through the drive imagery and came across this Navcam frame (posted above), which looks down on the Murray Buttes and Bagnold Dune Field, across Aeolis Palus and the northern rim of Gale crater. It’s pretty spectacular to see just how much we’ve explored in 5 years. But that was just a quick glance over Curiosity’s shoulder (or the RTG, which hangs off the back of the rover), because our sights were mostly set on the terrain ahead of us to choose where to go next.
I was the Geology Science Theme Lead today, and it felt like any other planning day. We came in to assess how the weekend activities completed, what targets we had in front of us, and which route we wanted to take to get to the next interesting feature on Vera Rubin Ridge. The two-sol plan begins with a preload test of the rover’s drill. Then Curiosity will acquire ChemCam and Mastcam observations of some nodular purple bedrock (target ‘Buck Reef’), and a unique gray-white vein or clast (target ‘Boomplaas’). We also planned some Mastcam imaging of sedimentary structures exposed in cross-section (target ‘Eccles’) and to document the previously-acquired ChemCam AEGIS target. Then Curiosity will drive ~15-20 m further south to investigate some mottled outcrop that we first noticed from orbit. After the drive, we’ll take Mastcam and Navcam images to prepare for contact science in the next plan. Data volume was a challenge today, so we had to think carefully about which images we need to have down in time to make decisions on Wednesday. On the second sol, Curiosity will wake up early to acquire a number of environmental monitoring observations to monitor clouds, dust, and wind. Later on the second sol we planned another ChemCam AEGIS observation to automatically target bedrock in our new location. Not bad for a typical day in the office!
Written by Lauren Edgar, Planetary Geologist at USGS Astrogeology Science Center
In light of the recent success of the Magit Kickstarter (congratulations to @tarsius, by the way), I got a lot more optimistic about Free Software crowdfunding.
So I opened a Patreon account where you can support my work: https://www.patreon.com/abo_abo. The goal I set there is both optimistic and (hopefully) realistic: I'd like to hack on Free Software 1 day per week indefinitely, reducing my real world job days to 4 per week.
Ideally, I'd like to work on Free Software full time (one can dream), but it doesn't look like that level of donations is attainable right now. But I think I could accomplish a lot working a full day per week:
Here's a list of popular repositories I've made over the last 5 years in my free time (all Free Software under GPL):
If you are a user of my work, don't feel any pressure to donate. We are all here voluntarily: I publish because I enjoy it, you use the software because you find it useful. But out there is the real world, and, although I like my real world job enough, I can't say that would I do it voluntarily if I had enough money to meet my needs.
If you do what you love, you'll never work a day in your life
I'd like to do what I love, and I wish you all the same. Happy hacking!
Last weekend, after five years of construction and controversy, the tiny and isolated British island of Saint Helena welcomed its first scheduled commercial flight. Saint Helena, a British Overseas Territory in the South Atlantic Ocean, is one of the most remote islands in the world—a volcanic outcrop with an area of only 47 square miles. According to Reuters, the only way to access the island previously was by sea, “a five-night voyage from Cape Town.” The new airport, servicing the 4,500 island inhabitants with flights from South Africa, was built at a cost of $374 million. Construction was completed in 2016, but test flights ran into serious weather-related problems, pushing the opening back more than a year, leading to the nickname “world’s most useless airport.” Gathered here are a handful of images from the inaugural flight and from around Saint Helena.
If your workflow involves administering remote systems or something similar, you probably have the following burned into your muscle memory. If, on the other hand, you’re like me and don’t have occasion to need root access on a remote machine very often, you can probably use a reminder. If you’re in the second category, here, courtesy of abo-abo, you go:
#Emacs open a file with ssh + sudo: C-x C-f /ssh:cloud|sudo:root:/etc/passwd
Works with Ivy too, but you get completion only after :/.
— abo-abo (@_abo_abo) October 17, 2017
If you click on the tweet, you’ll see the next tweet, which explains that “cloud” is the name of a remote system defined in abo-abo’s ~/.ssh/config. Defining often used remote systems like this is something I do too and it saves me a bunch of time and mental cycles trying to remember domains or, worse yet, IP addresses.
Assembly instructions on Mike Rankin’s blog:
Design files and source are available on GitHub:
This Sensor Board is yet another variation of another one on my site. It is not for sale with no real purpose in mind but the design files to make your own are here. The project was created as design challenge. My full time job is pcb design work and as a hobby I enjoy experimenting with new design ideas.
This was one of the more challenging designs I’ve worked on in a while. A few times I’d given up on routing it. Evan using four routing layers I found it tough. The idea was to hide the bezel of the display behind the board but have sensor components on that same board. It would look something like a little tiny television with all the components around the edges.
This latest revision has fixed a few issues I found on previous versions but the design idea can possibly help others in some way. Full credit goes to Adafruit for publishing the Feather M0 design files along with the bootloader. I used the Feather design to create the schematic for my board.
A security flaw in Infineon smart cards and TPMs allows an attacker to recover private keys from the public keys. Basically, the key generation algorithm sometimes creates public keys that are vulnerable to Coppersmith's attack:
While all keys generated with the library are much weaker than they should be, it's not currently practical to factorize all of them. For example, 3072-bit and 4096-bit keys aren't practically factorable. But oddly enough, the theoretically stronger, longer 4096-bit key is much weaker than the 3072-bit key and may fall within the reach of a practical (although costly) factorization if the researchers' method improves.
To spare time and cost, attackers can first test a public key to see if it's vulnerable to the attack. The test is inexpensive, requires less than 1 millisecond, and its creators believe it produces practically zero false positives and zero false negatives. The fingerprinting allows attackers to expend effort only on keys that are practically factorizable.
This is the flaw in the Estonian national ID card we learned about last month.
The paper isn't online yet. I'll post it when it is.
Ouch. This is a bad vulnerability, and it's in systems -- like the Estonian national ID card -- that are critical.
Because of the major version number change, there’s no packages built for DragonFly 4.9. Your options are to either update to 5.1 (which you probably meant to do anyway if you are running current) or manually point to the newest packages. Or just build from dports.
For clarity, this does not affect you at all if you are running 5.0 release. It only affects you if you are running DragonFly-current and have not updated in a while.
Michael W. Lucas is talking tonight at SemiBUG’s monthly meeting, and will be presenting on Tarsnap. Go, if you are near Michigan.
One hundred and thirty million years ago in a galaxy 130 million light-years away, two neutron stars met their fate, merging as one. Trapped in a gravitational embrace, these two stellar husks spiraled closer and closer until they violently ripped into one another, causing a detonation that reverberated throughout the cosmos.
On August 17, the U.S.-based Laser Interferometer Gravitational-Wave Observatory (LIGO) and Italian Virgo gravitational wave detector felt the faint ripples in spacetime from that ancient neutron star collision washing through our planet. Until now, LIGO and Virgo have only confirmed the collisions and mergers of black holes, so the fact that a nearby (a relative term in this case) neutron star merger had been detected was already historic.
But the implications for this particular neutron star signal, which is comparatively weak in comparison with the black hole mergers that have come before it, are so profound that I’ve been finding it hard to put this grand discovery into words (though I have tried).
With regards to gravitational waves, I feel I’ve described each gravitational wave discovery as “historic” and “a new era for astronomy” since their first detection on Sept. 15, 2015, but the detection of GW170817 may well trump all that have come before it, even though the signal was generated by neutron stars and not black hole heavyweights.
The thing with black holes is that when they collide and merge, they don’t necessarily produce electromagnetic radiation (i.e. visible light, X-rays or infrared radiation). They can go “bump” in the cosmic night and no intelligent being with a conventional telescope would see it happen. But in the the gravitational domain, black hole mergers echo throughout the universe; their gravitational waves travel at the speed of light, warping spacetime as they propagate. To detect these “invisible” waves, we must build instruments that can “see” the infinitesimal wobbles in the fabric of spacetime itself, and this is where laser interferometry comes in.
Very precise lasers are fired down miles-long tunnels in “L” shaped buildings in the two LIGO detectors (in Washington and Louisiana) and the Virgo detector near Pisa. When gravitational waves travel through us, these laser interferometers can measure the tiny spacetime warps. The more detectors measuring the same signal means a more precise observation and scientists can then work out where (and when) the black hole merger occurred.
There are many more details that can be gleaned from the gravitational wave signal from black hole mergers, of course — including the progenitor black holes’ masses, the merged mass, black hole spin etc. — but for the most part, black hole mergers are purely a gravitational affair.
Neutron stars, however, are a different beast and, on Aug. 17, it wasn’t only gravitational wave detectors that measured a signal from 130 million light-years away; space telescopes on the lookout for gamma-ray bursts (GRBs) also detected a powerful burst of electromagnetic radiation in the galaxy of NGC 4993, thereby pinpointing the single event that generated the gravitational waves and the GRB.
And this is the “holy shit” moment.
As Caltech’s David H. Reitze puts it: “This detection opens the window of a long-awaited ‘multi-messenger’ astronomy.”
What Reitze is referring to is that, for the first time, both gravitational waves and electromagnetic waves (across the EM spectrum) have been observed coming from the same astrophysical event. The gravitational waves arrived at Earth slightly before the GRB was detected by NASA’s Fermi and ESA’s INTEGRAL space telescopes. Both space observatories recorded a short gamma-ray burst, a type of high-energy burst that was theorized (before Aug. 17) to be produced by colliding neutron stars.
Now scientists have observational evidence that these types of GRBs are produced by colliding neutron stars as the gravitational wave fingerprint unquestionably demonstrates the in-spiraling and merger of two neutron stars. This is a perfect demonstration of multi-messenger astronomy; where an energetic event can be observed simultaneously in EM and gravitational waves to reveal untold mysteries of the universe’s most energetic events.
The fact that the gravitational waves and gamma-rays arrived at approximately the same time is yet another nod to Einstein’s general relativity. The century-old theory predicts that gravitational waves should travel at the speed of light and, via this brand spanking new way of doing multi-messenger astronomy, physicists and astronomers have again bolstered relativity with observational evidence.
But why did the gravitational waves arrive slightly before the GRB? Well, NASA’s Fermi team explains: “Fermi’s [Gamma-ray Burst Monitor instrument] saw the gamma-ray burst after the [gravitational wave] detection because the merger happened before the explosion,” they said in a tweet.
In other words, when the two neutron stars collided and merged, the event immediately dissipated energy as gravitational waves that were launched through spacetime at the speed of light — that’s the source of GW170817 — but the GRB was generated shortly after.
As the neutron stars smashed together, huge quantities of neutron star matter were inevitably blasted into space, creating a superheated, dense volume of free neutrons. Neutrons are subatomic particles that form the building blocks of atoms and if the conditions are right, the neutron star debris will undergo rapid neutron capture process (known as “r-process”) where neutrons combine with one another faster than the newly-formed radioactive particles can decay. This mechanism is responsible for synthesizing elements heavier than iron (elements lighter than iron are formed through stellar nucleosynthesis in the cores of stars).
For decades astronomers have been searching for observational evidence of the r-process in action and now they have it. Soon after the merger, massive amounts of debris erupted in a frenzy of heavy element creation, triggering an energetic eruption known as a “kilonova” that was seen as a short GRB. The GRB was cataloged as “SSS17a.”
Follow-up observations by the Hubble Space Telescope, Gemini Observatory and the ESO’s Very Large Telescope have all detected spectroscopic signatures in the afterglow consistent with the r-process taking place at the site of the kilonova, meaning heavy elements are being formed and, yes, it’s a goldmine. As in: there’s newly-synthesized gold there. And platinum. And all the other elements heavier than iron that aren’t quite so sexy.
And there’s lots of it. Researchers estimate that that single neutron star collision produced hundreds of Earth-masses of gold and platinum and they think that neutron star mergers could be the energetic process that seed the galaxies with heavy elements (with supernovas coming second).
So, yeah, it’s a big, big, BIG discovery that will reverberate for the decades to come.
The best thing is that we now know that our current generation of advanced gravitational wave detectors are sensitive enough to not only detect black holes merging billions of light-years away, but also detect the nearby neutron stars that are busy merging and producing gold. As more detectors are added and as the technology and techniques mature, we’ll be inundated with merging events big and small, each one teaching us something new about our universe.
Both gravitational and electromagnetic radiations have been detected in
Where did the
The seasons on Mars are long, and even though Curiosity is near the equator, the change in weather between the seasons is noticeable and winter is coming to Gale Crater. Right now it’s late fall in the southern hemisphere on Mars and the colder weather changes how we operate Curiosity. In colder weather, we need more power to heat the instruments and keep Curosity’s electronics and mechanisms warm. This reduces the amount of electricity we have to conduct science, but we were still able to prepare a full plan for the next two sols.
We identified two new bedrock targets to analyze with ChemCam (‘Woodlands’ and ‘Montecristo’, which are near the bottom portion of this image: https://mars.nasa.gov/msl/multimedia/raw/?rawid=NLB_560929716EDR_F0661332NCAM00279M_&s=1841). For Sol 1843, we also planned a series of Mastcam images of nearby bedrock targets that were analyzed with ChemCam as well as interesting spots in the distance, including a layered ledge on the Vera Rubin Ridge and a possibly hematite-rich patch called ‘Iron Mask’ which we may drive near in the future. We also will drive approximately 22 m towards our next target on Sol 1843.
For Sol 1844, we planned an expansive series of environmental monitoring activities. As we approach winter, the martian atmosphere gets cloudier and we planned a series of Navcam movies to search for clouds as well as a triplet of Mastcam images to determine the amount of dust and ice in the atmosphere and how it varies over the day. We additionally planned two Navcam movies to search for dust devils.
Written by Scott Guzewich, Atmospheric Scientist at NASA’s Goddard Space Flight Center
We are pleased to announce that the Provincial Archives of Saskatchewan is embarking on a digital preservation program based on Archivematica (for preservation) and AtoM (for online access)! The Provincial Archives of Saskatchewan is the provincial agency responsible for acquiring, preserving and making available records of significance to the history of the Province of Saskatchewan. The Archives holds an extensive and diverse Permanent Collection of historical records which include public documents created by governments ranging from the Territorial period to modern day, as well as records from private citizens, businesses and institutions dating from the mid-19th century to recent times. We are looking forward to working with Curt Campbell, Manager of the Preservation Management Unit & Digital Records Program, and his team at http://saskarchives.com/.
Researchers this week published information about a newfound, serious weakness in WPA2 — the security standard that protects all modern Wi-Fi networks. What follows is a short rundown on what exactly is at stake here, who’s most at-risk from this vulnerability, and what organizations and individuals can do about it.
Short for Wi-Fi Protected Access II, WPA2 is the security protocol used by most wireless networks today. Researchers have discovered and published a flaw in WPA2 that allows anyone to break this security model and steal data flowing between your wireless device and the targeted Wi-Fi network, such as passwords, chat messages and photos.
“The attack works against all modern protected Wi-Fi networks,” the researchers wrote of their exploit dubbed “KRACK,” short for “Key Reinstallation AttaCK.”
“Depending on the network configuration, it is also possible to inject and manipulate data,” the researchers continued. “For example, an attacker might be able to inject ransomware or other malware into websites. The weaknesses are in the Wi-Fi standard itself, and not in individual products or implementations. Therefore, any correct implementation of WPA2 is likely affected.”
What that means is the vulnerability potentially impacts a wide range of devices including those running operating systems from Android, Apple, Linux, OpenBSD and Windows.
As scary as this attack sounds, there are several mitigating factors at work here. First off, this is not an attack that can be pulled off remotely: An attacker would have to be within range of the wireless signal between your device and a nearby wireless access point.
More importantly, most sensitive communications that might be intercepted these days, such as interactions with your financial institution or browsing email, are likely already protected end-to-end with Secure Sockets Layer (SSL) encryption that is separate from any encryption added by WPA2 — i.e., any connection in your browser that starts with “https://”.
Also, the public announcement about this security weakness was held for weeks in order to give Wi-Fi hardware vendors a chance to produce security updates. The Computer Emergency Readiness Team has a running list of hardware vendors that are known to be affected by this, as well as links to available advisories and patches.
“There is no evidence that the vulnerability has been exploited maliciously, and Wi-Fi Alliance has taken immediate steps to ensure users can continue to count on Wi-Fi to deliver strong security protections,” reads a statement published today by a Wi-Fi industry trade group. “This issue can be resolved through straightforward software updates, and the Wi-Fi industry, including major platform providers, has already started deploying patches to Wi-Fi users. Users can expect all their Wi-Fi devices, whether patched or unpatched, to continue working well together.”
Sounds great, but in practice a great many products on the CERT list are currently designated “unknown” as to whether they are vulnerable to this flaw. I would expect this list to be updated in the coming days and weeks as more information comes in.
Some readers have asked if MAC address filtering will protect against this attack. Every network-capable device has a hard-coded, unique “media access control” or MAC address, and most Wi-Fi routers have a feature that lets you only allow access to your network for specified MAC addresses.
However, because this attack compromises the WPA2 protocol that both your wireless devices and wireless access point use, MAC filtering is not a particularly effective deterrent against this attack. Also, MAC addresses can be spoofed fairly easily.
To my mind, those most at risk from this vulnerability are organizations that have not done a good job separating their wireless networks from their enterprise, wired networks.
I don’t see this becoming a major threat to most users unless and until we start seeing the availability of easy-to-use attack tools to exploit this flaw. Those tools may emerge sooner rather than later, so if you’re super concerned about this attack and updates are not yet available for your devices, perhaps the best approach in the short run is to connect any devices on your network to the router via an ethernet cable (assuming your device still has an ethernet port).
From reading the advisory on this flaw, it appears that the most recent versions of Windows and Apple’s iOS are either not vulnerable to this flaw or are only exposed in very specific circumstances. Android devices, on the other hand, are likely going to need some patching, and soon.
If you discover from browsing the CERT advisory that there is an update available or your computer, wireless device or access point, take care to read and understand the instructions on updating those devices before you update. Failing to do so with a wireless access point, for example can quickly leave you with an expensive, oversized paperweight.
Finally, consider browsing the Web with an extension or browser add-on like HTTPS Everywhere, which forces any site that supports https:// connections to encrypt your communications with the Web site — regardless of whether this is the default for that site.
For those interested in a deeper dive on the technical details of this attack, check out the paper (PDF) released by the researchers who discovered the bug.
In September 2015 a star in Cygnus was observed by the Kepler Satellite; unlike the millions of other stars observed in the Kepler field of view this star demonstrated a very unique light curve. And unlike many of the interesting transits found by Kepler the first identification was done by Citizen Scientists on planethunters.org. This marked a major milestone for crowd sourced science and provided an amazing collaboration between professional and amateur scientists.
Four decades ago Jimmy Carter was sworn in as the 39th president of the United States, the original Star Wars movie was released in theaters, the Trans-Alaska pipeline pumped its first barrels of oil, New York City suffered a massive blackout, Radio Shack introduced its new TRS-80 Micro Computer, Grace Jones was a disco queen, the Brazilian soccer star Pele played his “sayonara” game in Japan, and much more. Take a step into a visual time capsule now, for a brief look at the year 1977.
Mathy Vanhoef has just published a devastating attack against WPA2, the 14-year-old encryption protocol used by pretty much all wi-fi systems. Its an interesting attack, where the attacker forces the protocol to reuse a key. The authors call this attack KRACK, for Key Reinstallation Attacks
This is yet another of a series of marketed attacks; with a cool name, a website, and a logo. The Q&A on the website answers a lot of questions about the attack and its implications. And lots of good information in this ArsTechnica article.
There is an academic paper, too:
"Key Reinstallation Attacks: Forcing Nonce Reuse in WPA2," by Mathy Vanhoef and Frank Piessens.
Abstract: We introduce the key reinstallation attack. This attack abuses design or implementation flaws in cryptographic protocols to reinstall an already-in-use key. This resets the key's associated parameters such as transmit nonces and receive replay counters. Several types of cryptographic Wi-Fi handshakes are affected by the attack. All protected Wi-Fi networks use the 4-way handshake to generate a fresh session key. So far, this 14-year-old handshake has remained free from attacks, and is even proven secure. However, we show that the 4-way handshake is vulnerable to a key reinstallation attack. Here, the adversary tricks a victim into reinstalling an already-in-use key. This is achieved by manipulating and replaying handshake messages. When reinstalling the key, associated parameters such as the incremental transmit packet number (nonce) and receive packet number (replay counter) are reset to their initial value. Our key reinstallation attack also breaks the PeerKey, group key, and Fast BSS Transition (FT) handshake. The impact depends on the handshake being attacked, and the data-confidentiality protocol in use. Simplified, against AES-CCMP an adversary can replay and decrypt (but not forge) packets. This makes it possible to hijack TCP streams and inject malicious data into them. Against WPA-TKIP and GCMP the impact is catastrophic: packets can be replayed, decrypted, and forged. Because GCMP uses the same authentication key in both communication directions, it is especially affected.
Finally, we confirmed our findings in practice, and found that every Wi-Fi device is vulnerable to some variant of our attacks. Notably, our attack is exceptionally devastating against Android 6.0: it forces the client into using a predictable all-zero encryption key.
I'm just reading about this now, and will post more information
as I learn it.
EDITED TO ADD: This meets my definition of brilliant. The attack is blindingly obvious once it's pointed out, but for over a decade no one noticed it.
EDITED TO ADD: Matthew Green has a blog post on what went wrong. The vulnerability is in the interaction between two protocols. At a meta level, he blames the opaque IEEE standards process:
One of the problems with IEEE is that the standards are highly complex and get made via a closed-door process of private meetings. More importantly, even after the fact, they're hard for ordinary security researchers to access. Go ahead and google for the IETF TLS or IPSec specifications -- you'll find detailed protocol documentation at the top of your Google results. Now go try to Google for the 802.11i standards. I wish you luck.
The IEEE has been making a few small steps to ease this problem, but they're hyper-timid incrementalist bullshit. There's an IEEE program called GET that allows researchers to access certain standards (including 802.11) for free, but only after they've been public for six months -- coincidentally, about the same time it takes for vendors to bake them irrevocably into their hardware and software.
This whole process is dumb and -- in this specific case -- probably just cost industry tens of millions of dollars. It should stop.
Nicholas Weaver explains why most people shouldn't worry about this:
So unless your Wi-Fi password looks something like a cat's hairball (e.g. ":SNEIufeli7rc" -- which is not guessable with a few million tries by a computer), a local attacker had the capability to determine the password, decrypt all the traffic, and join the network before KRACK.
KRACK is, however, relevant for enterprise Wi-Fi networks: networks where you needed to accept a cryptographic certificate to join initially and have to provide both a username and password. KRACK represents a new vulnerability for these networks. Depending on some esoteric details, the attacker can decrypt encrypted traffic and, in some cases, inject traffic onto the network.
But in none of these cases can the attacker join the network completely. And the most significant of these attacks affects Linux devices and Android phones, they don't affect Macs, iPhones, or Windows systems. Even when feasible, these attacks require physical proximity: An attacker on the other side of the planet can't exploit KRACK, only an attacker in the parking lot can.
DragonFly 5.0.0 has been released. HAMMER2 is available in the installer. Multi-volume/clustering support isn’t in there yet, but support for deduplication/snapshots/booting and so on all are. My post to users@ has upgrade instructions.
We’ve hit a run of clear skies, so it feels like a shopping spree up there. Anything a skywatcher might want to see — sunsets, meteors, a last look at Saturn, the Milky Way, the latest comets — is easy pickings. It’s no wonder the hobby of astronomy can drive some people crazy with its boom and bust cycles in the everlasting battle with the clouds.
If you’ve got good weather, take advantage of the late sunrise to step outside and gawk at a great gathering of a splinter-thin crescent moon just 1° (two moon diameters) from the planet Mars tomorrow morning (Oct. 17). Only 6° below the pair, you’ll see the beacon of Venus like a spotlight directing your eyes to the action. Start looking about an hour-and-a-half before sunrise in the eastern sky or around 6 a.m. low in the eastern sky. All three rise higher in a brightening sky as the sun works its way to the horizon.
From mid-October through November is the best time to catch sight of another dawn phenomenon, the zodiacal light. It’s a big cone of diffuse light, broader at its base and tapering along its length, that tilts up from the eastern horizon shortly before the start of dawn. The soft, glowing nature of the light resembles the smoky look of the Milky Way. But while the Milky Way’s misty appearance comes from the combined light of billions of distant suns, the zodiacal light originates from the sunlight scattered off quadrillions (at least!) of tiny, dust-mote sized comet grains and bits of asteroid debris.
The dust nearest the sun gets lit up brightest, hence the bright and broad base of the cone. The farther you look up and away from the sun’s direction, the less intense the scattered light, the reason the cone tapers and fades. It’s an eerie thing to see and worth getting up a little earlier. The zodiacal light is easily visible from a dark, eastern sky starting about two hours before sunrise, but most impressive at the very start of twilight about 90 minutes before sunrise, when the eastern sky begins to brighten.
The crescent moon is thin and faint enough that the zodiacal light should return to view — at least faintly — tomorrow morning. After that through about Nov. 2nd, when the moon returns to the morning sky, it’s open season on comet dust watching!
Integral (The International Gamma-Ray Astrophysics Laboratory) Image credit: ESA
Editor’s note: The news earlier this week was, indeed, exceptional (see “Integral sees blast travelling with gravitational waves”). ESA’s venerable gamma-ray observatory, Integral played a crucial role in this first-ever simultaneous ground-and space-based observation of a cataclysmic gamma-ray burst, which emitted both electromagnetic radiation and gravitational waves across billions of light-years of space.
Integral’s spacecraft operations manager Richard Southworth sent in this report, providing a glimpse behind the scenes of the intense activity at ESA’s ESOC mission control centre in Darmstadt, Germany, that helped make this incredible scientific achievement possible.
Coincidentally, on 17 October, Integral celebrated its 15th year in orbit, demonstrating impressive longevity for a hugely successful mission.
On the afternoon of Thursday, 17 August, Integral was approaching the end of science operations conducted during revolution 1,851 (they are numbered sequentially starting with revolution 1 on launch day in 2002), and, for the Flight Control Team at ESOC, it had not been a smooth day.
The team were in the process of planning routine flight activities for the upcoming orbit 1853, when a new set of urgent, high-priority science observations were received from the Integral Science Operations Team at ESA’s ESAC centre near Madrid; these had to be checked, processed and scheduled for flight operations, replacing the previous, already scheduled observation plan.
Murphy’s Law immediately swung into effect: That afternoon, both the prime and back-up mission planning engineers from our team were unavailable due to leave. While the other engineers on the Integral Flight Control Team are cross-trained to handle mission planning should a short-notice target of opportunity arise, re-planning always takes a little extra care and coordination if you’ve not done it in a while.
Murphy jumped on us again: Around midday a network failure affecting one of the 2 branches of the ESOC operations local area network, occurred, affecting all missions. This meant that we were flying the spacecraft and conducting the urgent replanning using the backup Mission control system. While the prime network was soon available again, capacity was reduced and we continued to conduct all Integral operations from the backup system.
Around 16:00 CEST, I received a call from our rather excited project scientist, Erik Kuulkers, at Estec in the Netherlands, asking whether we could accept and re-plan yet again for an additional target of opportunity that would occur in the very next orbit, due to start shortly after midnight.
Furthermore, he asked if we could urgently extract telemetry data – science information – from Integral that was stored at our Kiruna ground station (due to the aforementioned network problem at ESOC) and forward this directly to the science data centre in Geneva.
I checked and confirmed the availability of one of our engineers to process and schedule the new observation plan, which would have to be done after normal working hours; in addition, our hard-working flight dynamics support team would have to step in for this.
In my conversation with Erik, I asked him what was so urgent.
He was strangely cagey with his answer, but it soon became apparent when reading the details of this urgent request that it had been passed to ESA by scientists working with the LIGO / VIRGO observatories.
This could only mean one thing! In short, one of the main aims of our Integral mission was about to be achieved, that being the detection of the electromagnetic gamma-ray signature generated by a cataclysmic event, which had also been seen in the form of a gravitational wave.
All of us on the Flight Control Team got down to work, and time was of the essence.
The target of opportunity request was triggered at 15:58 CEST; by 19:49 CEST, the command files were ready in the mission control system, waiting only for the satellite to rise into view above Kiruna ground station to establish a data link and upload the commands.
This was a rather fast for Integral re-planning! From Initial request from science to operational files on the control system in less than four hours.
Despite running on the back-up system, execution of the operations was flawless: the commands were uploaded, Integral, our faithful, 15-year-old orbiting observatory reoriented itself in space to point it’s prime instruments at the target, and science data recording began at 06:50 CEST on 18 August.
That marked the end of an intense day but not the end of our story.
The next day, on 18 August, our project scientist received a correction to the position estimate of the target and requested an urgent re-plan of the currently executing observations, an even more complex and challenging planning exercise for our team.
Nevertheless, planning the new command schedule went smoothly and by mid-afternoon Integral was observing the new target location.
In the next several days, we received two more urgent re-targeting requests in support of this exceptional scientific opportunity. Again these were implemented without incident.
And now the incredible news is out, and everyone working on Integral operations couldn’t be more delighted to have contributed to this once-in-a-lifetime event.
As spacecraft operations manager, I can confirm that this exceptional set of observations were only possible due to:
These factors are part of what makes mission control at ESOC robust, reliable and effective, year-in, year-out.
These take years of patient development, planning, practice and investment to achieve on both the human and technical side, and are part of what makes ESA’s mission control centre one of Europe’s – and the world’s – best.
What better illustration can there be? Fifteen years in orbit constantly evolving, always ready for that one moment, so that even when the fates are against us we can still deliver.
When we announced the Hackaday Prize with its Best Product category, [PK] polled his wife and co-workers about the idea of making a desktop monitor using 6″ 800×600 ePaper, which he has since built and calls the PaperBack. One such requirement for a monitor is to be able to connect to it using one of…
via Hackaday Prize Entry: PaperBack Desktop ePaper Monitor — Hackaday
The world’s unexpected reaction to the launching of Sputnik on October 4, 1957 proved to be of immense propaganda value to the Soviet Union (see “Sputnik: The Launch of the Space Age”). People around the world could clearly see for themselves in the night sky this first artificial Earth satellite and the even brighter spent rocket which launched it into orbit challenging the American image of technological preeminence taken for granted by so many. With reaction to the launch of Sputnik (and its implications for national security) bordering on near panic among some in the US, a response to the Soviet challenge was desperately needed.
The launch of Sputnik on October 4, 1957 made headlines across the globe and shocked many Americans.
On October 11, 1957 the Eisenhower administration officially announced that an upcoming test flight of the Naval Research Laboratory’s Vanguard rocket would attempt to orbit a small satellite (see “Vintage Micro: The First Nanosatellite”). But with the scheduled launch date still a couple of months away, the American public was desperate to see a more immediate answer to Sputnik. As it turned out, they would not have to wait too long due to the efforts of a gifted Swiss astronomer working at Caltech named Fritz Zwicky (1898-1974).
Fritz Zwicky in a lighter moment later in life. (Caltech)
Born in 1898 in Varna, Bulgaria where his Swiss father was a prominent industrialist, Fritz Zwicky moved to Switzerland at age six to live with his paternal grandparents and attend school. Zwicky studied mathematics, engineering and physics at the prestigious Swiss Federal Institute of Technology in Zurich and received his doctorate in 1922. In 1925, Zwicky accepted a fellowship from the Rockefeller Foundation he was offered for his graduate work in quantum mechanics and went to teach at the California Institute of Technology (Caltech).
After coming to the US, Zwicky eventually shifted the focus of his career to observational astronomy becoming a staff member at the Mount Wilson Observatory and Palomar Observatory where he specialized in the study of galaxies. Working with German astronomer Walter Baade at Mount Wilson, Zwicky and Baade were the first to realize in 1933 the difference between ordinary nova in our galaxy and the intrinsically much brighter versions observed in some recently recognized “island universes” or galaxies now called supernova – a term Zwicky and Baade invented. Based on his studies of the motions of galaxies, in 1937 Zwicky was the first to determine that there must be unseen dark matter present to keep these clusters from fly apart.
Fritz Zwicky shown at work in 1936 at the Palomar Observatory’s 46-cm Schmidt telescope. (Caltech)
In 1943 during the height of World War II, Fritz Zwicky was asked to head the research department at the then-new Aerojet Engineering Corporation (the forerunner of Aerojet General which is now part of the rocket engine manufacturer, Aerojet Rocketdyne). While continuing his astronomical research, Zwicky worked on the development of new jet engine technology in his new role as industrial consultant. Following the war, Zwicky became part of the American team assembled by the Department of Defense to travel to Europe and evaluate German rocket technology. Upon his return, Zwicky started to work on how V-2 rocket technology could be employed in the study of the upper atmosphere of the Earth.
At this time, observations of meteors could be used to characterize the properties of the upper atmosphere as they flashed out of existence high above the Earth’s surface. Zwicky proposed creating artificial meteors using shaped charges carried to high altitude by a rocket to propel a slug of metal to hypervelocities. Shaped charges of the sort used in early antitank weapons could accelerate such a slug to velocities comparable to the 10 to 15 kilometer per second speed of the explosives’ detonation wave to produce a visible artificial meteor of known mass and composition allowing the characterization of the physical and chemical properties of the upper atmosphere at altitudes of 40 to 110 kilometers.
V-2 Number 17 used for Fritz Zwicky’s first artificial meteor experiment is shown here being prepared for its launch on December 17, 1946. (Peter Alway)
Using his connections through Aerojet and as a member of Science Advisory Board of the US Air Force, in the spring of 1946 Fritz Zwicky proposed using a captured V-2 rocket to loft his payload of shaped charges to create artificial meteors which would be observed using ground-based telescopes. His proposal was approved and the mission was launched on the evening of December 17, 1946 at 10:12 PM MST from the White Sands Proving Ground in New Mexico. While V-2 Number 17 operated as intended reaching a peak altitude of 188 kilometers, the shaped charges failed to detonate as planned at altitudes of 37, 46 and 55 kilometers probably due to a wiring error. Although Zwicky and his team gathered valuable data on the properties of the ascending rocket’s plume and its interaction with the graphite steering vanes used by the V-2 for attitude control, they failed to create artificial meteors for study.
Because of this failure and subsequent doubts voiced by some key experts in the field, Zwicky’s subsequent requests to refly his experiment were not approved. Undeterred, Zwicky and his team continued their work to improve their hardware and techniques as well as prove that shaped charges could be used to create observable artificial meteors. Ground tests performed in 1947 at the US Navy’s facility at China Lake, California demonstrated that shaped charges could create hypervelocity projectiles bright enough to be observed from ranges of hundreds of kilometers using the portable Palomar 20-centimeter Schmidt telescope. During subsequent years, Zwicky and his associates at Aerojet continued work with shaped charges and developing new explosives. Encouraged by this work, the US Navy sponsored a series of successful tests using high altitude balloons in 1955.
Cutaway diagram showing the major components of the Aerobee sounding rocket. Click on image to enlarge. (NASM)
With these successes in hand, approval was given to fly an updated artificial meteor experiment on an Aerobee sounding rocket when space became available. The Aerobee was a two-stage sounding rocket originally developed for the US Navy by Aerojet under the guidance of the Applied Physics Laboratory at Johns Hopkins University. Later, upgraded version were designed and built for the US Navy, USAF and eventually NASA. The first stage consisted of a solid rocket motor which boosted the rocket and its payload to high speeds so that its fins could stabilize the rocket by the time it left its launch tower. The liquid fueled second stage, originally based on work done by Caltech’s Jet Propulsion Laboratory for the WAC Corporal missile, would provide the bulk of the energy to hurl its payload to the edge of space. Although the typical Aerobee payload of a few tens of kilograms was much smaller than that of the V-2 (which was really too large for most early experiments), this purpose-built sounding rocket was much less expensive, easier to launch and more flexible than its larger cousin.
In the summer of 1957, Fritz Zwicky and his collaborators finally got word that they could refly the artificial meteor experiment as part of an Aerobee launch already scheduled for mid-October. Sponsored by the Geophysics Research Directorate of the Air Force Cambridge Research Center, the payload contained three separate shaped charge packages using a common detonator and arranged so that their firing would not interfere with each other. One of the packages was supplied by a group headed by Dr. Thomas Poulter of Stanford University and consisted of an almost cylindrical aluminum plug designed to maximize its velocity. A second package with a larger one-centimeter aluminum plug supplied by a group headed by Dr. John S. Rinehart of the Smithsonian Astrophysical Observatory would travel at a slower velocity. The third package was fabricated by Zwicky’s team and consisted of a 1.5 millimeter aluminum cone propelled by C3 explosives supplied by the USAF.
A view of the three packages of shaped charges mounted on the Aerobee rocket prior to launch. (Caltech)
At 10:05 PM MST on October 16, 1957, the Aerobee rocket carrying the artificial meteor experiment lifted off from Holloman Air Force Base in New Mexico. After 45 seconds, the second stage of the Aerobee had exhausted its propellant and continued its climb out of the atmosphere. Ten seconds later, the artificial meteor payload was separated at an altitude of 56 kilometers leaving the other payload still attached to the rocket to perform its separate mission. After coasting for another 36 seconds, the shape charges were detonated at an altitude of about 85 kilometers. The resulting flash was easily observed from not only the cameras and telescopes deployed in the region, where it appeared as bright as -10 magnitude, but also using the 46-centimeter and 1.2-meter Schmidt telescopes at the Palomar Observatory 1,000 kilometers away where it appeared as a -5 to -6 magnitude green flash.
An enlargement of a telescopic image showing one of the jets emerging from the shape charge detonation flash in the upper left. (Caltech)
Subsequent evaluation of the data showed that two jets containing hypervelocity aluminum pellets were clearly observed propagating upwards. While the slower moving jet corresponding to a heavier metal slug was measured to be moving at only 3 to 5 kilometers per second and would arc back to Earth, the velocity of the particles in the brighter jet was at least 15 kilometers per second. Zwicky reasoned that since the atmosphere above 85 kilometers was so tenuous resulting in little loss in momentum, these particles would have surely exceeded Earth’s 11.2 kilometer per second escape velocity and proceeded into solar orbit. Although proving beyond any doubt that some of these particle were actually in solar orbit would be a real world example of Russell’s teapot orbiting somewhere between the planets (an analogy posited by philosopher Bertrand Russell to illustrate that the burden of proof lies upon a person making unfalsifiable claims), the analysis strongly supported the claim that the US had been the first to launch artificial objects into solar orbit.
Diagram showing the calculated trajectory of the fastest pellets propelled into solar orbit during the October 16, 1957 artificial meteor experiment. Click on image to enlarge. (Caltech)
After over a decade of effort, Zwicky’s artificial meteor experiment not only proved to be a success, it also provided the US with a much needed (albeit minor) morale boost in the wake of Sputnik. Although Zwicky had grand plans for further advancements of this technology to aid in the exploration of space, the world’s focus soon turned to more conventional rocketry to provide data on the space environment leaving this interesting footnote in the early history of the Space Age.
Zwicky’s artificial meteor experiment made headlines and helped provide at least a minor boost to American morale in the wake of the Sputnik launch.
Follow Drew Ex Machina on Facebook.
“Sputnik: The Launch of the Space Age”, Drew Ex Machina, October 4, 2017 [Post]
David H. DeVorkin, Science with a Vengeance: How the Military Created the US Space Sciences after World War II, Springer-Verlag, 1992
Stephen M. Maurer, “Idea Man”, Beam Line, pp. 21,27, Winter 2001
Fritz Zwicky, “Research with Rockets”, Publications of the Astronomical Society of the Pacific, Vol. 59, No. 347, pp. 64-73, April 1947
Fritz Zwicky, “The First Shots into Interplanetary Space”, Engineering and Science, Vol. 20, No. 4, pp. 20-23, January 1958
“Artificial Meteor”, Sky & Telescope, Vol. 17, No. 3, p. 111, January 1958
KrebsOnSecurity was honored this month with the 2017 President’s Award for Public Service from the Information Systems Security Association, a nonprofit organization for cybersecurity professionals. The award recognizes an individual’s contribution to the information security profession in the area of public service.
It’s hugely gratifying to have received this award, mainly because of the company I now keep.
Past ISSA President’s Award winners include former White House cybersecurity advisers Richard A. Clarke (2003) and the late Howard Schmidt (2016); DEF CON and Black Hat founder Jeff Moss (2011); Hacking Exposed authors George Kurtz, Stuart McClure and Joel Scambray (2015); as well as Liam O’Murchu, Eric Chien, and Nicolas Falliere, the team at Symantec credited for their groundbreaking analysis of the Stuxnet Worm (2012).
“[Krebs’] analysis of the bad actors and the dark web shines a light on the criminals and their methods that attack information security,” the ISSA said in explaining the award. “The information that he exposes to the light of day makes the jobs of white hats and blue teamers easier.”
I’m very grateful to the ISSA for this award, and wish a hearty congratulations to the other ISSA 2017 award recipients.
I might add that the chocolate bunny is hollow, because often the things that bring momentary pleasure, like chocolate, are unfulfilling in the end. Of course, sometimes the bunny is full of nougat, to symbolize the mysterious ways in which the Lord works, because nobody knows what nougat is.
I could do this all day.
Note from Missy: I feel like this was a grand experiment at the time: a comic with no narration, only dialog. Was this the only time you did it, Scott?
Note from Scott: I think I did two one-panel comics for Thanksgiving this way. Every other comic was done in my usual wall-of-text style.
As always, thanks for using my Amazon Affiliate links (US, UK, Canada).
Time for another Remacs update: lots of contributions, a wide range of features, and even a logo!
Since the last update, we’ve seen contributions from lots of new people. We’ve added @brotzeit and @shanavas786, bringing us to seven wonderful people who can approve your PRs.
Speaking of PRs, we’ve merged an amazing 64 pull requests since the last update!
If you’re looking for a good feature for your first contribution, @brotzeit has been regularly adding new suggestions under the ‘good first issue’ label.
Many Emacs features have now been ported to Rust, with new Rust APIs for accessing elisp datastructures.
Here’s an overview of the features that have landed.
Arithmetic: arithmetic, floating point, random number generation (using a Rust RNG!), and comparisons.
Symbols: symbol properties, interning, obarrays unbinding, keywords and indirect symbols.
Checksums: MD5sum (using a Rust MD5 crate!).
Windows: liveness check, type check, overlays and minibuffer, minibuffer check positions and margins.
Processes: accessing, type check, data structures and names.
Buffers: for the current thread, accessing, file names, size and modification.
Point: bobp, bolp, eolp, markers, point-min, point-max forward-point and goto-char.
Hash tables: copying and accessing.
Characters: multibyte conversions, character tables, category tables
Fonts: type checks.
Miscellaneous: prefix arguments and identity.
We’re also periodically pulling GNU Emacs features into Remacs, so all the features available GNU Emacs trunk are included in Remacs.
Remacs has gradually developed a set of conventions for elisp data
types. For each type Foo, we define a LispObject::as_foo,
LispObject::as_foo_or_error and a FooRef when you know your elisp
datatype is actually a Foo.
For example, here’s how overlay-start was implemented in C:
DEFUN ("overlay-start", Foverlay_start, Soverlay_start, 1, 1, 0,
doc: /* Return the position at which OVERLAY starts. */)
(Lisp_Object overlay)
{
CHECK_OVERLAY (overlay);
return (Fmarker_position (OVERLAY_START (overlay)));
}The C codebase makes heavy use of macros for checking types
(CHECK_OVERLAY) and for accessing struct attributes
(OVERLAY_START).
Here’s the Rust equivalent:
/// Return the position at which OVERLAY starts.
#[lisp_fn]
fn overlay_start(overlay: LispObject) -> LispObject {
let marker = overlay.as_overlay_or_error().start();
marker_position(marker)
}We use procedural macros to simplify defining an elisp primitive function, and type checking is much more explicit.
(This example is from PR #298.)
Other exciting Rusty features
include
variadic macros to replace call1, call2 in C with just call! in Rust,
and
the ability to mock extern C functions so we can write unit tests.
We’re not always able to leverage the Rust libraries available. @DavidDeSimone showed some amazing Rust-fu exploring using Rust’s FnvHashMap inside Remacs.
Sadly, we weren’t able to use the Rust hash map implementation. The C
layer assumes that it can mutate hash table keys in place, and
unexec does not play nicely with mmap. See the PR for the full details.
Finally, we’re discussing a logo for Remacs. We’ve had some great submissions:
You can join the logo discussion at PR #360.
As always, if you fancy writing some Rust in support of the world’s lispiest text editor, you can join us on GitHub!