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Jul
16
comment Can modern twistor methods to calculate scattering amplitudes be applied to renormalization group calculations?
In the "Outlook" chapter, "A clear goal would be to understand the physics of the renormalization group along these lines". I suspect the short answer to Dilatons question is "yes" and he'd have to ask N A-H for the long answer.
Jul
15
comment String Theory and Standard Model in CERN
+1. This is the only answer (so far) mentioning the uses of string theory in learning to calculate the SM predictions well enough.
Sep
24
comment Harold White's work on the Alcubierre warp drive
I'm interested in the lab experiment too. Is it just creating the positive mass part to show the geometry works as it should?
Jan
19
comment How many colors exist?
Wikipedia on MacAdam ellipse
Jan
10
comment Can the implications of dark energy be used to bridge the gap between Quantum Mechanics and General Relativity?
What about us living in de Sitter space rather than AdS? I wouldn't be surprised if string theorists argued that ST predicts AdS if we didn't have the observed dark energy.
Jan
10
comment Why singularity in a black hole, and not just “very dense”?
+1, because the answers you got are very interesting
Oct
1
comment Graphene space elevator possible?
I feel I have to point out that the ISS weighs 450 tons. Geostationary orbit costs around twice as much as LEO.
Oct
1
comment Graphene space elevator possible?
@Zassounotsukushi It's not my idea; I linked to the source. 44 tons is not a limit for what's possible to launch. MIT claims they're working on the material. Assuming they succeed, how does that make a space elevator obsolete?
Sep
26
comment Graphene space elevator possible?
@dmkee: This page gives a list of cable weights for different strengths of material. The 130 GPa tensile strength quoted for graphene gives you a 44 ton cable capable of lifting a ton. Launching 44 tons to geostationary orbit should cost less than a billion. Admittedly, any loss of strength due to defects in the cable will quickly make the cable heavier. A halving of strength would roughly multiply the cost by a factor of ten.
Sep
25
comment Graphene space elevator possible?
Well, for the "no other market" argument; the article says it's 100 times more electrically conductive than copper and can transmit data 10 times faster than fiber optics. Both uses call for long sheets of graphene. In addition, MIT is actually working on it.
Sep
5
comment Why can you remove the gravitational constant from a computer game simulation?
Yes. It's just there because meters, kilograms and seconds have their own historical reasons for being as large they are.If you write a game, you don't have to care about such things. You obviously need to think about how strong gravity should be in your game, but you can tweak the masses to do that. If you want the strength of gravity to change dynamically in the game (say, become stronger over time) you could keep it as a variable, but there's no need for it as a constant.
Sep
2
comment How do we know that C14 decay is exponential and not linear?
+1 for the handful of coins analogy. The entire reason for exponential decay is that there is less stuff left that can decay.