evanb

67 ms·

811.
by evanb 10y ago
There are two things here. The force magnetic fields apply is always perpendicular to the field: F ~ v × B (right hand rule, and all that). So if you want F to point inward, the one component of B that doesn't matter is its radial co
812.
by evanb 10y ago
I was recently a postdoc at LLNL, and took a real-life 1-week in-person crash-course on pthreads, OpenMP and MPI from Blaise. Afterwards I really felt like I could get going. I guess it is not SUPER surprising---LLNL and LANL are basically
813.
by evanb 10y ago
All the LLNL computing tutorials are great---they tend to be clearly written, with good examples, and cover a wide swath of use cases. The OpenMP https://computing.llnl.gov/tutorials/openMP/ and MPI https:/
814.
by evanb 10y ago
Can you explain what you mean by > The fields in quantum field theory are mathematical tools, they are not physical entities. If you mean that the world itself is not the mathematics then I can accept it (although I might resist, the phi
815.
John Glenn, American Hero of the Space Age, Dies at 95(nytimes.com)
7 points by evanb 10y ago|0 comments
816.
by evanb 10y ago
Oh man. Can we change this to https://arxiv.org/abs/1608.06822 ? This "write up" is very bad, and clearly comes from somebody who doesn't really grasp quantum mechanics, and the connection to QUESS is.
817.
by evanb 10y ago
Something along these lines was recently in the news: http://usa.chinadaily.com.cn/china/2016-11/22/content_274557...
818.
by evanb 10y ago
I think you mean astrophysical, rather than galactic? Galactic structures are well-explained by Newtonian gravity (assuming dark matter, but that's independent of whether you describe gravity as Newton or Einstein did). Large-scale s
819.
by evanb 10y ago
No. Vacuum birefringence is understandable from a perfectly conventional understanding of quantum field theory, and does not remotely require anything about the pilot wave idea to be true. Every quantum field theory, including QED, has a
820.
by evanb 10y ago
Its properties also help constrain nuclear physics at high A and Z, which is needed for understanding astrophysical nucleosynthesis and hunts for the island of stability.
821.
Brexit 'not good news for British science' warn new Nobel laureates(theguardian.com)
3 points by evanb 10y ago|0 comments
822.
by evanb 10y ago
"He's going to be all right." "Oh, thank god!" "Finally, some good news from this guy!" "That's a great attitude. I gotta tell you, if I were getting this news I don't know that I'd t
823.
by evanb 10y ago
Lithium isn't in the top 10 most abundant chemical elements in the universe ( https://en.wikipedia.org/wiki/Abundance_of_the_chemical_elem... ). The most abundant, of course, is hydrogen, making up close to 74% o
824.
FCC official: “Something’s not right” with Wi-Fi at Monday’s debate(arstechnica.com)
6 points by evanb 10y ago|1 comments
825.
by evanb 10y ago
A pretty standard laundry list of no-go items and then... > * collection of charitable donations; !! This seems really different from all the other prohibitions. What's the idea behind that?
826.
Waste not want not: Sweden to give tax breaks for repairs(theguardian.com)
1 points by evanb 10y ago|0 comments
827.
Struggles with the Continuum (Part 1) – Azimuth(johncarlosbaez.wordpress.com)
2 points by evanb 10y ago|0 comments
828.
Big bad modifier order(languagelog.ldc.upenn.edu)
4 points by evanb 10y ago|0 comments
829.
by evanb 10y ago
MIT has 4 mandatory quarters of PE, plus a swimming test (or a swim class).
830.
by evanb 10y ago
Well then, I guess my strategy accomplishes nothing!
831.
by evanb 10y ago
Numbered hats: I'm not sure this is optimal. When the prisoners are together, they assign each person a unique ID from 1 to 100. Once the round starts, each looks around and adds up the total on everybody else's hat, mod 100. Su
832.
by evanb 10y ago
Although you allege ekke's comment was "much better understandable", it commits the same use of they as singular. > Others follow a simple pattern - if the light is off, and they have never turned it on yet, turn it on. If
833.
by evanb 10y ago
You have to be careful, because if the light starts out on, Mr C could be fooled when only 98 other people have entered the room.
834.
by evanb 10y ago
Ugh. This gives me a headache.
835.
by evanb 10y ago
Let F be the only person who is permitted to turn the light oFF. The N be every body else---they will be turning the lights oN. F starts with a counter at 0. If the light is on when F gets to the room, they turn the light off, and they incr
836.
by evanb 10y ago
As I said above to another commenter, if you can explain all the observational signatures https://en.wikipedia.org/wiki/Dark_matter#Observational_evid... in another way, you should write a paper! If you don't con
837.
by evanb 10y ago
The issue is the speed of light is so big. So, you need a LOT of energy in order to source gravity comparably to just a little bit of mass (essentially, because E=mc^2 -- or perhaps phrased more clearly in this case, m = E/c^2). Even
838.
Dark arts – A bodily pigment may have industrial uses(economist.com)
1 points by evanb 10y ago|0 comments
839.
by evanb 10y ago
Well, if you can explain all the observational signatures https://en.wikipedia.org/wiki/Dark_matter#Observational_evid... in another way, you should write a paper! If your idea is simply "that's all bullshit
840.
by evanb 10y ago
As long as we're being pedantic nerds: dark matter is not "anything not emitting visible light", although such matter is "dark" in common parlance. Dark matter is called dark because it does not interact electromag

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