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Elastic properties of spacetime

by AbsoluteChaos
Tags: distortion, gravity, mass, spacetime
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mattp913
#19
Apr25-11, 12:01 AM
P: 4
The universe is cooler today than it was right after the big bang
Chalnoth
#20
Apr25-11, 03:43 AM
Sci Advisor
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Quote Quote by mattp913 View Post
The universe is cooler today than it was right after the big bang
Yes, but that temperature exists as radiation.
mattp913
#21
Apr26-11, 02:28 AM
P: 4
Right, so my question was could that temperature be inversely proportional to the distance of space-time? The universe is cooling and expanding. Also, as an object approaches the speed of light, distances contract. The mass(potential energy) of matter can affect the shape of space-time, so the temperature(kinetic energy) of matter in space-time may also affect its shape.
Chalnoth
#22
Apr26-11, 04:31 AM
Sci Advisor
P: 4,802
Quote Quote by mattp913 View Post
Right, so my question was could that temperature be inversely proportional to the distance of space-time? The universe is cooling and expanding. Also, as an object approaches the speed of light, distances contract. The mass(potential energy) of matter can affect the shape of space-time, so the temperature(kinetic energy) of matter in space-time may also affect its shape.
Yes, the temperature of matter in space-time has an impact. However, normal matter and dark matter are effectively zero-temperature today for this sort of consideration (temperature only really matters when it is high enough that the particles are relativistic). It was a significant consideration very early on, when the temperature of normal matter was so high that the typical energy of, say, an electron was much higher than its mass energy. But that isn't the case any longer.

And while the photons are obviously still relativistic (they are relativistic at any temperature), their total energy density is only a tiny fraction of the energy density in matter, so that their effect on the curvature of space-time is minimal.


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