Slashdot Mirror
Motion of the Primordial Universe Revealed
neutron_p writes "New results from an instrument located high in the Chilean Andes (the Cosmic Background Imager) are giving researchers a clearer view of what the universe looked like in the first moments following the Big Bang. Cosmologists observe a time in the universe's distant past when atoms were first forming. The findings reveal the first movements between these "seeds" that ultimately led to clusters of early galaxies."
The press release at the CBI website is much more informative.
The big news is that they've measured the polarized power spectrum, and it agrees extremely well with the theoretical predictions. Which means that not only do the density fluctuations match what's expected, but the matter is moving in the gravitational field of those density fluctuations exactly as expected.
[TMB]
Yes. During inflation the universe expanded not at several times the speed of light, but rather doubled its size every 10^-34 of a second. After about a hundred doublings the inflationary period ended and expansion slowed to (locally) sub-light speeds.
The microwave background didn't come from the big bang though. It was actually emitted from the surface of last scattering when the universe became transparent for the first time--around 300k years after the big bang.
The "center of the universe" is not well-defined. If the universe is topologically closed, then it has neither center nor boundary, like the surface of the earth. If the universe is topologically open, then it is infinite in size and similarly has neither center nor boundary.
TTFN
Pardon me but if the universe expanded in such a manner wouldn't that be against the theory of relativity. What about breaking causality?
Well IANAP, but I'll explain what I understand of it.
Relativity requires that no signal can travel faster than the speed of light. During inflation, nearby parts of the universe move away from each other faster than the speed of light. However, because there is no signal traveling FTL, causality is not violated.
TTFN
Several others have tried to answer, but I don't think you got any clear and correct answer.
The thing that is confusing you is that you have the very common image of the big bang being like a hand grenade explosion in the vacuum of space. You are picturing there is some point in the middle of our universe that was the center, from which everything spread out. The big bang is is no normal explosion, it was an explosion of space not in space, and there is no center in our universe.
In order to explain a picture of what it *is* like we need to imaging the universe is 2D instead of 3D. Imagine we live in a 2D sheet of rubber rather than 3D space. Now lets curve that sheet of rubber around into a ballon. We live in the surface of that ballon. There is *nothing* inside or outside the skin of the ballon - not even a vacuum. Our universe *is* the skin. You, me, the sun, the stars, they are specs within that skin.
That ballon is expanding. In the past the was smaller. Imagine running backwards, srhinking that ballon down to a point. That point would be the big bang. It was in the past, sort of in the center of our current ballon. That point is not anywhere in our universe, it is not on the skin of the ballon.
Now to explain the microwaves we see from the big bang. When you run backwards all of the stars and dust and gas were closer together in the skin of that smaller ballon. Go back far enough and everything in our universe was squashed togther - everywhere. There was very little space itself for it all to fit in. All of the space in our universe was filled with a dense hot soup of glowing particles.
So that glow came from everywhere in our universe. No matter what direction we look, that point umpteen billion light years away was glowing umpteen billion years ago. The very spot we are at now was glowing umpteen billion years ago, and if someone billions of light years from here were to look at us they would see that old glow from here.
Did that make sense?
-
- - You can't take something off the Internet! That's like trying to take pee out of a swimming pool.