Freethought & Rationalism Archive

eh · 10-10-2002, 02:32 PM

Why don't join us in the string theory forum? <a href="http://superstringtheory.com/forum/forums_i.html" target="_blank">http://superstringtheory.com/forum/forums_i.html</a>

I'm no expert in superstrings, but can take a stab at it.

if I understand correctly the energy bands (or whatever strings are made of) have a supposedly enormous tension, greater than, say, a bar of steel. Even if a thing with such a tension is small, wouldn't it need to get energy from somewhere to vibrate? And wouldn't it slow down?

This seems to be a question of exactly what energy is. In string theory, the loops of string are just vibrating strings of energy. In this theory, there is nothing more fundemental than these strings. The string can't slow down, because there is no lower state it can reach. Obviously, you'll find a much better explanation on the string theory board.

And why do they only vibrate at the rates which produce the handful of elementary particles?
Why isn't there an infinite number of elementary particles, if there is no law or process governing how or why the strings vibrate?

String theory predicts there should be an infinite number of particles. Since we do not see an infinite amount, this should prove string theory to be false, right? Well not quite. The basic idea is that there are many different types of particles that should be discovered in the future. Since the vibrational pattern of the string determines the particle, we should be able to find certain particles predicted by this theory.

So while we haven't observed many of these exotic particles, string theory predicts we eventually will. The exact physics of strings might put a limit on the amount of vibrations that will exist in our universe, but a more detailed explaination is required. Check out the forums I linked above.

luvluv · 10-10-2002, 02:55 PM

eh, I've tried. The email shoots me to the login page which then asks me for a password I have not been asked to set. I keep going around in circles.

In the meantime, though, if there were an infinite number of particles, shouldn't we have run across a few by now? Shouldn't they be all over the place?

Nat · 10-10-2002, 05:08 PM

Luvluv,

I think you are getting caught up in the analgoies used by physicists to explain these concepts. Think of these vibrations and the tension of the string in the same way one thinks about particle spin. It is mathematically useful to use the idea of spin, but particle physicists don't actually claim that particles (which are not thought of as "little balls" like the name seems to imply) actually "spin" in the macroscopic way. Similarly, Green and Witten and other String Theorist are not really using terms like "vibrate" and "tension" in the literal macroscopic meaning of these words. These are useful analogs that allow us to describe things that are not really describable in everyday terms.

[ October 10, 2002: Message edited by: Nat ]

galiel · 10-10-2002, 10:31 PM

Quote:

Originally posted by Nat:
 These are useful analogs that allow us to describe things that are not really describable in everyday terms.

Quite correct. Somewhat off-topic but stream-of-my-somewhat-consciousness related, this reminds me of the depressing fact that many high-school text books still show illustrations of the atom like a little solar system, with discrete electron planets orbiting a solid nucleus. And we wonder why so many people still think the stork brung 'em.

Peter Soderqvist · 10-10-2002, 11:00 PM

Stephen Hawking Quest For A Theory Of everything, by Kitty Ferguson, chapter 2, page 24: Combining the two ideas, we must conclude that the entire universe ought to be curled up into a small ball. This hasn't happened. When general relativity and quantum mechanics work together, what they predict seems be dead wrong. Both general relativity and quantum mechanics are exceptionally good theories, two of the outstanding intellectual achievements of the twentieth century. They serve us magnificently not only for theoretical purposes but in many practical ways. Nevertheless, put together they yield infinites and nonsense. The Theory of Everything must somehow resolve that nonsense.

The Theory of Everything: The Origin and Fate of the Universe, by Stephen Hawking on amazon.com
<a href="http://www.amazon.com/exec/obidos/ASIN/1893224546/qid=1030966131/sr=2-3/ref=sr_2_3/002-8491418-6368863" target="_blank">http://www.amazon.com/exec/obidos/ASIN/1893224546/qid=1030966131/sr=2-3/ref=sr_2_3/002-8491418-6368863</a>

[ October 11, 2002: Message edited by: Peter Soderqvist ]

eh · 10-11-2002, 01:53 PM

Quote:

Originally posted by luvluv:
eh, I've tried. The email shoots me to the login page which then asks me for a password I have not been asked to set. I keep going around in circles.

In the meantime, though, if there were an infinite number of particles, shouldn't we have run across a few by now? Shouldn't they be all over the place?

Odd. Did you try e-mailing the site admin about the problem? It might be a browser or cookie issue.

10-10-2002, 05:08 PM	#13
Nat Regular Member Join Date: May 2002 Location: USA Posts: 100	Luvluv, I think you are getting caught up in the analgoies used by physicists to explain these concepts. Think of these vibrations and the tension of the string in the same way one thinks about particle spin. It is mathematically useful to use the idea of spin, but particle physicists don't actually claim that particles (which are not thought of as "little balls" like the name seems to imply) actually "spin" in the macroscopic way. Similarly, Green and Witten and other String Theorist are not really using terms like "vibrate" and "tension" in the literal macroscopic meaning of these words. These are useful analogs that allow us to describe things that are not really describable in everyday terms. [ October 10, 2002: Message edited by: Nat ]</p>

10-10-2002, 11:00 PM	#15
Peter Soderqvist Regular Member Join Date: Oct 2001 Location: Sweden Stockholm Posts: 233	Stephen Hawking Quest For A Theory Of everything, by Kitty Ferguson, chapter 2, page 24: Combining the two ideas, we must conclude that the entire universe ought to be curled up into a small ball. This hasn't happened. When general relativity and quantum mechanics work together, what they predict seems be dead wrong. Both general relativity and quantum mechanics are exceptionally good theories, two of the outstanding intellectual achievements of the twentieth century. They serve us magnificently not only for theoretical purposes but in many practical ways. Nevertheless, put together they yield infinites and nonsense. The Theory of Everything must somehow resolve that nonsense. The Theory of Everything: The Origin and Fate of the Universe, by Stephen Hawking on amazon.com <a href="http://www.amazon.com/exec/obidos/ASIN/1893224546/qid=1030966131/sr=2-3/ref=sr_2_3/002-8491418-6368863" target="_blank">http://www.amazon.com/exec/obidos/ASIN/1893224546/qid=1030966131/sr=2-3/ref=sr_2_3/002-8491418-6368863</a> [ October 11, 2002: Message edited by: Peter Soderqvist ]</p>

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10-10-2002, 02:32 PM	#11
eh Senior Member Join Date: Sep 2000 Location: Canada Posts: 624	Why don't join us in the string theory forum? <a href="http://superstringtheory.com/forum/forums_i.html" target="_blank">http://superstringtheory.com/forum/forums_i.html</a> I'm no expert in superstrings, but can take a stab at it. if I understand correctly the energy bands (or whatever strings are made of) have a supposedly enormous tension, greater than, say, a bar of steel. Even if a thing with such a tension is small, wouldn't it need to get energy from somewhere to vibrate? And wouldn't it slow down? This seems to be a question of exactly what energy is. In string theory, the loops of string are just vibrating strings of energy. In this theory, there is nothing more fundemental than these strings. The string can't slow down, because there is no lower state it can reach. Obviously, you'll find a much better explanation on the string theory board. And why do they only vibrate at the rates which produce the handful of elementary particles? Why isn't there an infinite number of elementary particles, if there is no law or process governing how or why the strings vibrate? String theory predicts there should be an infinite number of particles. Since we do not see an infinite amount, this should prove string theory to be false, right? Well not quite. The basic idea is that there are many different types of particles that should be discovered in the future. Since the vibrational pattern of the string determines the particle, we should be able to find certain particles predicted by this theory. So while we haven't observed many of these exotic particles, string theory predicts we eventually will. The exact physics of strings might put a limit on the amount of vibrations that will exist in our universe, but a more detailed explaination is required. Check out the forums I linked above.

10-10-2002, 02:55 PM	#12
luvluv Veteran Member Join Date: Mar 2002 Location: Planet Lovetron Posts: 3,919	eh, I've tried. The email shoots me to the login page which then asks me for a password I have not been asked to set. I keep going around in circles. In the meantime, though, if there were an infinite number of particles, shouldn't we have run across a few by now? Shouldn't they be all over the place?

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