Thread: Gravity
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Pazuzu Pazuzu is online now
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Location: Houston TX
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Quote:
Originally Posted by flatbutt View Post
This is the part that makes my head hurt. It's difficult to visualize space being the entirety of existence with no borders up against anything else. I accept the red shift of the universe but how can it expand into nothing thereby creating more of something?
I'm accustomed to a finite existence. For the universe to expand my mind says that it must expand into another space or dimension.

As stated my ape brain is better at defining the limits that I will work within whether it be confidence limits or an LoQ specification.
We cannot visualize it at all, but mathematically it all makes sense. 4 dimensional spacetime, and we are a 3 dimensional universe within it. Dots drawn on the surface of a balloon (3D spacetime, 2D universe) all see the other dots moving away as the balloon expands, but none of them can calculate the size of the 2D universe, nor the edge of the 2D universe, nor the center of the 2D universe. Their 2D minds and basic geometry simply won't let them see or understand that their 2D universe is wrapped around a 3D object.

We are a 3D universe wrapped in 4 dimensions. We cannot see the edge, cannot find the center, nor can we determine the size of the universe, but it is still finite in size, and expanding in a mathematically understandably way.

Quote:
Originally Posted by zakthor View Post
I thought we just discovered that gravity waves also move at speed of light - which is just space moving right?

I played this through in my head a few times and don't see why expansion had to be faster than C. Do you happen to have a thought experiment handy that explains why its necessary that expansion happened at more than c?
Inflation didn't HAVE to happen, but it did happen. That flattened the Universe (make a circle, then make the circle REALLY BIG, and the surface starts to appear flat, not curved). Inflation make the Universe appear flat, not curved. It made the somewhat chaotic stew of matter very homogeneous, since quantum fluctuations which might have appeared as very high density regions got smeared apart under inflation. The distribution of matter that because galaxies and such was spread so thin, that it is now basically equal in every direction.

Quote:
Originally Posted by island911 View Post
Yeah, I wasn't trying to suggest a prime mover of some sort.

I mean that's just not believable.
Obviously... there was nothing, and then it exploded.
There was the Higg's Field. That's not nothing, it was an energy field of negative potential energy that had a high enough value to spawn the Universe. How can you call that nothing?

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