Jonathan Langdale originally shared this post:

Back to the future

I've been trying to come to grips with the idea of time symmetry and time-reversal.  +Sean Carroll writes an interesting post about the recent B meson "arrow of time" experimental result that was announced recently. 

"The reason why it’s an impressive experiment is that it’s very difficult to directly compare the rate of one process to its precise time-reverse. You can measure the lifetime of a muon, for example, as it decays into an electron, a neutrino, and an anti-neutrino. But it’s very difficult (utterly impractical, actually) to shoot a neutrino and an anti-neutrino directly at an electron and measure the probability that it all turns into a muon."

What I'm struggling with is the idea of time reversal as distinguished by

1.  Going forward in time and constructing a muon from by-products coming together in the same way they decay

vs

2.  Going backwards in time from the by-products to a muon. 

There seems to be a fundamental difference between these two ideas.  If you're still going forward in time, is that really a time symmetry? It seems like it would be a different process than actual time-reversal. 
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Time-Reversal Violation Is Not the “Arrow of Time” | Cosmic Variance | Discover Magazine

arxiv | Looks like the good folks at the BaBar experiment at SLAC, feeling that my attention has been distracted by the Higgs boson, decided that they might be able to

Maybe we’ll start paying attention to history after we repeat it a few more times.

#history   #rome   #campaignreform   #citizensunited   #money   #politics   #culturalperspectives

Jürgen Hubert originally shared this post:

Relevant, as I have recently been reading about the Roman Republic.

How Political Campaign Spending Brought Down the Roman Republic

Two years after the Supreme Court’s decision in Citizens United, which allowed unlimited corporate and union money into American politics, there is one line that continues to echo: “The appearance of …

In Musk's vision, the ambitious Mars settlement program would start with a pioneering group of fewer than 10 people, who would journey to the Red Planet aboard a huge reusable rocket powered by liquid oxygen and methane.

Elon Musk wants to help put 80,000 people on the Red Planet.

A field full of pyramids, but on a micro scale. Each of the pyramids hides a living cell. Thanks to 3D micro- and nano scale fabrication, promising new applications can be found.

http://phys.org/news/2012-11-capturing-cells-micro-pyramids.html
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It’s getting to be that time again, when Mickey Mouse gets closer and closer to the public domain — and you know what that means: a debate about copyright term extension. As you know, whenever Micke…

Library of Congress pulls diaries, letters from those who experienced Civil War for exhibit

#war #history

http://www.washingtonpost.com/national/library-of-congress-pulls-diaries-letters-from-those-who-experienced-civil-war-for-exhibit/2012/11/24/323f9d5c-364d-11e2-92f0-496af208bf23_story.html?Post%2Bgeneric=%3Ftid%3Dsm_twitter_washingtonpost

WASHINGTON — Letters and diaries from those who lived through the Civil War offer a new glimpse at the arguments that split the nation 150 years ago and some of the festering debates that survive toda…

Make Space, Not War

Vote here: http://videoremix.freemusicarchive.org/video/160/make-space-not-war

You’ll have to sign up for a Free Music Archive account. It’s a great website and they provide a great service. The people who run it are awesome as well. Do it. I’d recommend it even to not vote for my video.

(Update: Nov 13, 2012: Having been able to sit back and no longer being lost in the trees. I see the forest and realize that I should’ve left a lot of the war and nuclear blast footage on the cutting room floor in order to make the argument/story flow better. The meat of the video doesn’t really get started until 4:34 in. Far too long. I plan to make and updated version and maybe even a TL:DR version.)

http://www.firstmenonthemoon.com/

They were building massively huge Intercontinental ballistic missiles (ICBM) in order to launch their awkwardly large and unsophisticated nuclear arsenal. The US was streamlining the tech. Going for quality and accuracy over quantity and brute force. This gave the Soviets the foundation and advantage in sending heavy launch capsules that carried satellites, animals, and eventually people into orbit.

I found this great information completely on accident.

I’m working on several video compilation projects for an upcoming contest. (Update: Here’s the contest entry – http://videoremix.freemusicarchive.org/video/160/make-space-not-war) I haven’t really made much in that arena and I need a good motivator, enforceable deadline, and would love to find out what latent talents the competition can bring out of me.

I was browsing Space.com and stumbled upon an article on Jon Glenn’s historic space flight back on February 20, 1962.

I tried finding the full video so I could download it and possibly use some clips for my current and future video remixing. First stop wasn’t a stretch: archive.org. Since my video compilation research was in that domain I figured might be a good shot to find the video and maybe some related to it. Didn’t hit pay dirt, but I did find some similar videos. A broader interweb search led me to c-span. Yes, that C-SPAN. But there was no easy way to download what I found: http://www.c-spanvideo.org/program/303736-1.

I then scoured Nasa.gov. Their footage – pictures, audio, and video – is public domain. It’s our well spent tax dollars that pay for all the greatness. But the closest thing I was able to find were pictures available to download from the History of Mercury Control. Great stuff and highly interesting, but not the video I was seeking.

Then I found it in one of the last places I would’ve thought it to reside: vimeo.

Friendship – 7 50th Anniversary from Guy Noffsinger on Vimeo.

Available in all it’s glory and even more than expected. A truly great documentary. Sit back and enjoy.