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Physics, Astronomy & Cosmology / How is expanding spacetime described in string theory?
« on: 30/11/2008 03:35:14 »
I'm having trouble understanding what it means when the expansion of the universe is explained in terms of expanding spacetime.
One way to cure my confusion might be to approach the problem in terms of string theory which, as I understand it, supposes spacetime is quantized. In this framework, then, does the expansion of space result from:
a. The quanta are moving further apart. But, if so, what's in between them?
b. The quanta are packed together perfectly and nothing is between them -- they're getting bigger. But, if so, what's inside them, and how is it getting bigger? Seems to me this answer leads to a nested-dolls problem.
c. The quanta are packed perfectly, nothing is between them, and they aren't getting bigger. (Perhaps their size is dictated by a fundamental constant.) Instead, new quanta are "bubbling" into existence from nowhere, shouldering the existing quanta apart and thereby creating more space. This isn't forbidden because no matter or energy is being created. But, if this is happening, the reverse process should work too, so what's causing the asymmetry?
d. Something else I haven't thought of.
One way to cure my confusion might be to approach the problem in terms of string theory which, as I understand it, supposes spacetime is quantized. In this framework, then, does the expansion of space result from:
a. The quanta are moving further apart. But, if so, what's in between them?
b. The quanta are packed together perfectly and nothing is between them -- they're getting bigger. But, if so, what's inside them, and how is it getting bigger? Seems to me this answer leads to a nested-dolls problem.
c. The quanta are packed perfectly, nothing is between them, and they aren't getting bigger. (Perhaps their size is dictated by a fundamental constant.) Instead, new quanta are "bubbling" into existence from nowhere, shouldering the existing quanta apart and thereby creating more space. This isn't forbidden because no matter or energy is being created. But, if this is happening, the reverse process should work too, so what's causing the asymmetry?
d. Something else I haven't thought of.