Notices by HN Tooter (hntooter@mastodon.social), page 13

HN Tooter (hntooter@mastodon.social)'s status on Monday, 25-Sep-2017 14:25:59 EDT HN Tooter

Why did science fiction stop moving forward?
https://lareviewofbooks.org/article/star-trek-discovery/
(submitted by rbanffy)
In conversation Monday, 25-Sep-2017 14:25:59 EDT from mastodon.social permalink
Attachments
1. Star Trek: Discovery - Los Angeles Review of Books
  
  from Los Angeles Review of Books
  
  Aaron Bady and Sarah Mesle for Dear TV ravenously consume two new hours of Star Trek: Discovery. What's the verdict? The present sucks.
HN Tooter (hntooter@mastodon.social)'s status on Monday, 25-Sep-2017 12:16:01 EDT HN Tooter

North Korea accuses US of declaring war
http://www.bbc.com/news/world-asia-41391978
(submitted by strayamaaate)
In conversation Monday, 25-Sep-2017 12:16:01 EDT from mastodon.social permalink
Attachments
1. N Korea accuses US of declaring war
  
  from BBC News
  
  Foreign Minister Ri Yong-ho says his country has the right to shoot down US bombers.
HN Tooter (hntooter@mastodon.social)'s status on Sunday, 24-Sep-2017 20:45:50 EDT HN Tooter

Australian government promises national space agency
http://www.zdnet.com/article/australian-government-commits-to-establishing-national-space-agency/#ftag=RSSbaffb68
(submitted by smokielad)
In conversation Sunday, 24-Sep-2017 20:45:50 EDT from mastodon.social permalink
Attachments
1. Australian government promises national space agency | ZDNet
  
  from ZDNet
  
  The Australian government has announced its commitment to establish a national space agency, following consultation with industry.
HN Tooter (hntooter@mastodon.social)'s status on Saturday, 23-Sep-2017 10:55:23 EDT HN Tooter

An American City Where the Government Barely Exists
http://splinternews.com/welcome-to-an-american-city-where-the-government-barely-1818667220
(submitted by rmason)
In conversation Saturday, 23-Sep-2017 10:55:23 EDT from mastodon.social permalink
Attachments
1. Welcome to an American City Where the Government Barely Exists
  
  from Splinter
  
  On Woodward Avenue in Highland Park, Michigan, a historical marker stands in front of a derelict industrial building. It reads, “Here at his Highland Park Plant, Henry Ford in 1913 began the mass production of automobiles on a moving assembly line...Mass production soon moved from here to all phases of American industry and set the pattern of abundance for 20th Century living.”
HN Tooter (hntooter@mastodon.social)'s status on Thursday, 21-Sep-2017 11:25:46 EDT HN Tooter

PocketBeagle is a $25 ultra-tiny-yet-complete open-source USB-key-fob computer
http://beagleboard.org/pocket
(submitted by jarmitage)

In conversation Thursday, 21-Sep-2017 11:25:46 EDT from mastodon.social permalink
HN Tooter (hntooter@mastodon.social)'s status on Thursday, 21-Sep-2017 10:46:10 EDT HN Tooter

The moon blew up without warning and for no apparent reason
https://jasmcole.com/2017/09/20/the-moon-blew-up-without-warning-and-for-no-apparent-reason/
(submitted by mhb)
In conversation Thursday, 21-Sep-2017 10:46:10 EDT from mastodon.social permalink
Attachments
1. The moon blew up without warning and for no apparent reason
  
  By jasmcole from Almost looks like work
  Intriguing title, no? These are the first eleven words of Neal Stephenson’s novel Seveneves, which set up the remaining 600 pages as an extended treatise on the future of humanity as it copes with certain annihilation. I thoroughly recommend it, as long as you can deal with hundreds of pages of orbital mechanics. In this post I will numerically explore this post-lunar age, to verify for myself if it would be as deadly as described.
  
  In the novel, one day the moon breaks up into 7 roughly equal-sized pieces. These pieces continue peacefully orbiting the Earth for a while, and eventually two pieces collide. This collision causes a piece to fragment, making future collisions more likely. The process repeats, at what Stephenson says is an exponential rate, until the Earth is under near-constant bombardment from meteorites, wiping out (nearly) all life on Earth.
  
  How likely is this? Let’s simulate the process numerically.
  
  Simulation design
  
  At the beginning of the simulation, there are 7 masses orbiting Earth in near circular orbits. In this model I include
  
  A static mass at the origin of a 2D co-ordinate system – this is Earth.
  
  Gravitational interactions between all bodies. I use an extraordinarily naive direct summation approach, which scales as and is horrible. A huge improvement would be to approximate forces from distant bodies with some kind of multipole expansion, and store masses in a balanced tree – this is known as a Barnes-Hut simulation.
  
  Pairwise collisions between bodies – most of the collisions are approximated as elastic, for which the post-collision velocities are easily calculated.
  
  Possible fragmentation of bodies – in this case one of the masses breaks into 2 equally-sized pieces, which fly off into different directions. Energy is conserved by subtracting kinetic energy from the other body in the collision. Additionally, I set a kinetic energy threshold for the fragmentation, such that smaller bodies have to collide at larger relative velocities for a fragmentation to occur.
  
  Energy-conserving integration – the temporal integration is performed with a Verlet (leapfrog) technique. This is important as it is the simplest of a class of numerical integrators called sympletic integrators, which have inherently bounded errors. (This is because they preserve volume in the phase space of the particle dynamics, and so are not susceptible to damping or growth of energy). Note that this is not true for simple integrators like the Euler or Runge-Kutta methods.
  
  Simulation results
  
  Let’s have a look at what this setup looks like – the case after a couple of orbits is plotted below. The Earth is at the origin, and the moon fragments start at a position (1,0), orbiting in a circular orbit in the anti-clockwise direction.
  
  I’ve set the ‘radius’ of Earth to be one fifth of the initial moon distance. This is much larger than reality, but it helped keep the simulation short. With my terrible and slow code, I needed to help everything evolve a bit more quickly!
  
  You can see the fragments have already started to interact, spreading out in the transverse and forward/rearward directions. There have also been a couple of fragmentations.
  
  A video of the entire simulation is below. On the left is a close-up view of the Earth, on the right is a running tally of meteorite impacts. An impact is defined as when a mass collides with the circle at the centre, and the mass is removed from the simulation. Every impact, the outline of Earth flashes red.
  
  As you can see, things start out gently but suddenly the number of impacts skyrockets, until eventually tailing off. This cumulative plot is expanded below.
  
  One of the events depicted in the book is the ‘white sky’, where the number of impacts grows exponentially until they are near-constant. Plotted on a logarithmic scale, there does appear to be an initial exponential phase in the simulation, lasting a relatively short time. Soon after, the impact rate slows but not to zero, with impacts occurring every so often for the remainder of the simulation. This is another scenario predicted in the book, where the planet takes many thousands of years to cool down after the initial heavy bombardment.
  
  However, as time goes on more and more of these collisions should be by lighter fragments, due to the increased fragmentation. The distribution of masses in orbit evolves as follows.
  
  Because collisions must happen at higher and higher relative velocities for smaller fragments, the mass distribution bottoms out here at around a ten-thousandth of the initial fragment mass. (This was again a deliberate decision in order to reduce the total number of fragments in the simulation.) After the initial burst of fragmentation, the population remains relatively stable. Continuing collisions don’t often cause fragmentation, but do direct fragments towards the Earth for a long time.
  
  As expected then, the mass of impacts drops with time in a very similar fashion:
  
  We can also track where the mass in the simulation ends up. As plotted below, over 25% ends up on the surface of the Earth! This is an enormous amount, the energy in gravitational potential alone is > J, or the equivalent of 10 billion Tsar Bombas.
  
  The rest of the mass, liberated by the spent gravitational potential energy of the rest of the fragments, is sent spinning out into space. We can observe this by plotting the distribution of distances of the fragments from Earth:
  
  The fragments hitting Earth eventually reach the dotted line, but you can also see the bulk of the population is rapidly speeding away. (In fact, in the simulation any fragment which reaches a large enough distance above the escape velocity there is removed from the simulation to save on computational time.)
  
  Next steps
  
  Writing this simulation and producing a nice video was a decent challenge, but there is much to improve. First is optimising the simulation to handle more than a thousand or so fragments, either by switching to a more efficient algorithm or parallelising with CUDA or similar. Second is to use a more realistic collision and fragmentation scenario, allowing for inelastic collisions and using a physically relevant model for the masses of daughter fragments.
  
  However, I think this simple model is enough to add some realism to the scenario Neal Stephenson wrote about. It also makes me glad the moon is still in one piece. Last I checked.
HN Tooter (hntooter@mastodon.social)'s status on Thursday, 21-Sep-2017 09:55:47 EDT HN Tooter

Distrustful U.S. allies force spy agency to back down in encryption fight
http://www.reuters.com/article/us-cyber-standards-insight/distrustful-u-s-allies-force-spy-agency-to-back-down-in-encryption-fight-idUSKCN1BW0GV
(submitted by petethomas)
In conversation Thursday, 21-Sep-2017 09:55:47 EDT from mastodon.social permalink
Attachments
1. Distrustful U.S. allies force spy agency to back down in encryption fight
  
  from U.S.
  
  An international group of cryptography experts has forced the U.S. National Security Agency to back down over two data encryption techniques it wanted set as global industry standards, reflecting deep mistrust among close U.S. allies.
HN Tooter (hntooter@mastodon.social)'s status on Thursday, 21-Sep-2017 09:55:47 EDT HN Tooter

SEC Discloses Edgar Corporate Filing System Was Hacked in 2016
https://www.wsj.com/articles/sec-discloses-edgar-corporate-filing-system-was-hacked-in-2016-1505956552
(submitted by k2enemy)
In conversation Thursday, 21-Sep-2017 09:55:47 EDT from mastodon.social permalink
Attachments
1. SEC Discloses Edgar Corporate Filing System Was Hacked in 2016
  
  from WSJ
  
  The SEC disclosed that hackers penetrated its electronic system for storing public-company filings and may have traded illegally on the information.
HN Tooter (hntooter@mastodon.social)'s status on Thursday, 21-Sep-2017 08:05:18 EDT HN Tooter

Why Are Middle East Girls Better in School Than Boys?
https://www.theatlantic.com/education/archive/2017/09/boys-are-not-defective/540204/?utm_source=feed&single_page=true
(submitted by SoMuchToGrok)
In conversation Thursday, 21-Sep-2017 08:05:18 EDT from mastodon.social permalink
Attachments
1. Why Are Middle Eastern Girls Crushing Boys in School?
  
  from The Atlantic
  
  A case study in motivation, mixed messages, and the condition of boys everywhere.
HN Tooter (hntooter@mastodon.social)'s status on Thursday, 21-Sep-2017 00:35:16 EDT HN Tooter

Peter Thiel Up for Key Intelligence Position, Wants to Limit Google's Power
https://gizmodo.com/report-peter-thiel-up-for-key-intelligence-position-w-1818591891
(submitted by dlp211)
In conversation Thursday, 21-Sep-2017 00:35:16 EDT from mastodon.social permalink
Attachments
1. Report: Peter Thiel Up for Key Intelligence Position, Wants to Limit Google's Power
  
  from Gizmodo
  
  According to a long-in-the-works report from Vanity Fair, Peter Thiel is in discussions to head what one insider described as the “only meaningful executive-branch oversight of the intelligence community.” Numerous officials, including Steve Bannon, confirmed this, and one of Thiel’s chief concerns is reportedly the sweeping powers that companies like Google and Amazon have amassed.
HN Tooter (hntooter@mastodon.social)'s status on Wednesday, 20-Sep-2017 15:56:03 EDT HN Tooter

A typewriter that sends its keystrokes in real time to a Google Doc
http://jsomers.net/blog/docwriter?hn=1
(submitted by jsomers)

In conversation Wednesday, 20-Sep-2017 15:56:03 EDT from mastodon.social permalink
HN Tooter (hntooter@mastodon.social)'s status on Tuesday, 19-Sep-2017 00:05:49 EDT HN Tooter

Toys 'R' Us files for Bankruptcy
https://www.toysrusinc.com/press/toysrus-inc-commences-court-supervised-processes-to-implement-financial-restructuring
(submitted by runesoerensen)

In conversation Tuesday, 19-Sep-2017 00:05:49 EDT from mastodon.social permalink
HN Tooter (hntooter@mastodon.social)'s status on Sunday, 17-Sep-2017 13:25:56 EDT HN Tooter

We've failed: open access is winning and we must change our approach
http://onlinelibrary.wiley.com/doi/10.1002/leap.1116/full
(submitted by mathgenius)
In conversation Sunday, 17-Sep-2017 13:25:56 EDT from mastodon.social permalink
Attachments
1. File without filename could not get a thumbnail source.
  
  We've failed: Pirate black open access is trumping green and gold and we must change our approach
  
  Sci‐Hub has made nearly all articles freely available using a black open access model, leaving green and gold models in its dust.Why, after 20 years of effort, have green and gold open access not achieved...
HN Tooter (hntooter@mastodon.social)'s status on Saturday, 16-Sep-2017 01:16:01 EDT HN Tooter

Taking PHP Seriously
https://slack.engineering/taking-php-seriously-cf7a60065329
(submitted by Mahn)
In conversation Saturday, 16-Sep-2017 01:16:01 EDT from mastodon.social permalink
Attachments
1. Taking PHP Seriously – Several People Are Coding
  
  from Several People Are Coding
  
  by Keith Adams, Slack Engineering
HN Tooter (hntooter@mastodon.social)'s status on Thursday, 14-Sep-2017 20:05:38 EDT HN Tooter

North Korea Launched Missile Over Japan Toward Pacific Ocean
https://www.bloomberg.com/news/articles/2017-09-14/north-korea-launched-missile-over-japan-toward-pacific-ocean
(submitted by schintan)
In conversation Thursday, 14-Sep-2017 20:05:38 EDT from mastodon.social permalink
Attachments
1. North Korea Launched Another Missile Over Japan Into Pacific
  
  from Bloomberg.com
  
  North Korea fired its second missile over Japan in as many months, a fresh provocation that comes shortly after the United Nations approved harsher sanctions against Kim Jong Un’s regime.
HN Tooter (hntooter@mastodon.social)'s status on Thursday, 14-Sep-2017 09:36:08 EDT HN Tooter

Bitcoin is dropping right now after a big Chinese exchange said it is closing
https://www.cnbc.com/2017/09/14/bitcoin-is-dropping-right-now-after-a-big-chinese-exchange-said-it-is-closing.html
(submitted by koolba)
In conversation Thursday, 14-Sep-2017 09:36:08 EDT from mastodon.social permalink
Attachments
1. Bitcoin is dropping right now after a big Chinese exchange said it is closing
  
  from CNBC
  
  Bitcoin prices fell about 7 percent on Thursday after one of the biggest exchanges in China said it will shut down its operation.
HN Tooter (hntooter@mastodon.social)'s status on Thursday, 14-Sep-2017 09:15:55 EDT HN Tooter

Chromium: FTP resources will be marked “Not Secure”
https://groups.google.com/a/chromium.org/forum/#!msg/security-dev/HknIAQwMoWo/xYyezYV5AAAJ
(submitted by stablemap)

In conversation Thursday, 14-Sep-2017 09:15:55 EDT from mastodon.social permalink
HN Tooter (hntooter@mastodon.social)'s status on Wednesday, 13-Sep-2017 11:55:58 EDT HN Tooter

Packaging Python software with pbr
https://julien.danjou.info/blog/2017/packaging-python-with-pbr
(submitted by pmoriarty)

In conversation Wednesday, 13-Sep-2017 11:55:58 EDT from mastodon.social permalink
HN Tooter (hntooter@mastodon.social)'s status on Tuesday, 12-Sep-2017 14:16:03 EDT HN Tooter

JPMorgan CEO Jamie Dimon says Bitcoin is a fraud that will eventually blow up
https://www.cnbc.com/2017/09/12/jpmorgan-ceo-jamie-dimon-raises-flag-on-trading-revenue-sees-20-percent-fall-for-the-third-quarter.html
(submitted by mudil)
In conversation Tuesday, 12-Sep-2017 14:16:03 EDT from mastodon.social permalink
Attachments
1. JPMorgan CEO Jamie Dimon says bitcoin is a fraud that will eventually blow up
  
  from CNBC
  
  JPMorgan Chase CEO Jamie Dimon took a shot at bitcoin, saying the cryptocurrency "is a fraud."
HN Tooter (hntooter@mastodon.social)'s status on Tuesday, 12-Sep-2017 09:36:09 EDT HN Tooter

North Korea Hackers Step Up Bitcoin Attacks
https://www.bloomberg.com/news/articles/2017-09-11/north-korea-hackers-step-up-bitcoin-attacks-amid-rising-tensions
(submitted by qu4ntumturk)
In conversation Tuesday, 12-Sep-2017 09:36:09 EDT from mastodon.social permalink
Attachments
1. North Korea Hackers Step Up Bitcoin Attacks
  
  from Bloomberg.com
  
  Prices and popularity are rising.

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Notices by HN Tooter (hntooter@mastodon.social), page 13