Comments on: String Theory Cribsheet

By: Don

Don — Fri, 27 Mar 2009 17:17:26 +0000

Link to the large version seems broken

By: Doug

Doug — Fri, 20 Apr 2007 02:09:33 +0000

The depicted sinusoidal strings [in 2D?] are probably helical strings in 3D.

This likehood seems to be well explained at this wevsite:

SIGNAL PROCESSING & SIMULATION NEWSLETTER
Copyright 1998 All Rights Reserved C. Langton, mntcastle@earthlink.net
Complex representation of Fourier series
[Euler's identity: -1 = e^{iPI}] = e^{jwt} = cos wt + i sin wt (1)
Figure 3 â€” e^(jwt) plotted in three dimensions is a helix
In Figure 3 cos wt is plotted on the Real axis and sin wt is plotted on the Imaginary axis. The function looks like a helix moving forward in time to the right. The X-Z and the Y-Z projections, if plotted, would be the sine and cosine functions.

http://www.complextoreal.com/tfft2.htm

By: slinkybender

slinkybender — Thu, 19 Apr 2007 23:57:23 +0000

I freind described the problem with string theory is that different people will come to different conclusions given the same set of data because it’s realy more of a belief system than a true science.

By: Not Even Wrong » Blog Archive » News From the Landscape and Elsewhere

Not Even Wrong » Blog Archive » News From the Landscape and Elsewhere — Thu, 19 Apr 2007 22:05:09 +0000

[...] Seed magazine has a series of “cribsheets” about science. For physics, they cover nuclear power, the elements, and now string theory. The lack of predictivity of the theory is given a positive spin as being due to the “rich diversity” of string theory. At Cosmic Variance, Sean Carroll approvingly refers to this as “it only refers glancingly to the anthropic principle, which is a much more accurate view of the state of discussion about string theory than one would get by reading blogs.” [...]

By: Thomas

Thomas — Thu, 19 Apr 2007 21:35:18 +0000

BG, clear sky can also be saturated with water vapor. What makes a cloud a cloud is the water that has condensed to water or ice. The lifetime of the individual droplets may be interesting if you want to explore the dynamics further but doesn’t change the basic fact that clouds do not consist of water vapor. No matter how far you want to simplify the science that is simply a lousy description.

Wikipedia, for example, starts its article as:
“A cloud is a visible mass of condensed droplets or frozen crystals suspended in the atmosphere above the surface of the Earth or another planetary body. “

By: Hektor Bim

Hektor Bim — Thu, 19 Apr 2007 16:32:23 +0000

The sentence about “string theory’s rich diversity” is quite strange. What diversity are they talking about – is there Latino string theory? Rich diversity seems like exactly what you don’t want in a theory. What you want is clarity and simplicity, which leads to a diverse array of predictions. It’s precisely in the range of diverse predictions that string theory is not diverse at all.

By: Khurram

Khurram — Thu, 19 Apr 2007 15:59:54 +0000

SEED is a great magazine. Although, when I first started reading it, I was a little taken aback. I was not used to seeing scientists glorified in this way before. It makes us seem hip and trendy. I still do not know how I feel about this but as long as they keep up the good writing, it’s OK.

By: BG

BG — Thu, 19 Apr 2007 15:41:20 +0000

Thomas: to say clouds are made of water droplets is as much of an oversimplification as to say that they’re water vapor. Clouds are a complicated equilibrium between condensing water droplets (or even ice crystals) and air that is saturated with water vapor. The actual lifetime of a droplet isn’t terribly long; they re-evaporate as they fall through the cloud.

Clouds reflect visible light and maybe some near IR, but they definitely do not reflect all IR wavelengths the way they do optical. The details depend on cloud composition. I’m sure you know that clouds have a very complicated effect on climate modeling; they’re probably one of the biggest sources of uncertainty, and volumes have been written about them.

Anyway, given the rather ridiculous task of simplifying a huge research area down to one page, statements like “Clouds are made up of concentrated greenhouse gas” are probably unavoidable.

By: Thomas

Thomas — Thu, 19 Apr 2007 11:45:26 +0000

Sean and BG, yes water vapor is a greenhouse gas, but clouds are not made of water vapor but of water droplets. Liquid water. Clouds affect the climate by *reflecting* visible as well as infrared light, not by absorbing IR as a greenhouse gas would. I suppose in some way you can call a liquid a concentrated gas, but it is misleading in this case.

By: Lab Lemming

Lab Lemming — Thu, 19 Apr 2007 07:33:59 +0000

Sean, the “elements” crib isa basically cosmology in disguise. Half the sheet is about the big bang, and the other half is about stars, cramming in fusion and S,R process nucleasynthesis without actually mentioning them by name or discribing how they differ.

According to the chart of elemental abundances, No elements heavier than tin exist, and fluorine has been relabeled as sodium.

There is absolutely no mention of chemistry whatsoever.