DeepAstronomy 3: RocketBoom Lady & the Size of the Universe

Okay, I am going to BLOW your mind away. Ready? The Universe expands because of . . . GRAVITY!! Assume an infinite Universe. Take any sphere of volume (4/3) pi r^3. Now take a larger sphere of V = (4/3) pi (2r)^3, so it's twice the diameter. Volume of Outer Shell = (4/3) pi (2r)^3 - (4/3) pi r^3 = 7(4/3) pi r^3. Outer shell therefore outgravitates inner sphere by 7 times. So Universe is pulled outwards by each bigger shell. And it accelerates! F = ma. May the Force be with you.

donottawaguitar riffs of space

haha " Naked Singularity "

so any idea whats outside the universe? and whats outside that?

No, it wasn't.

I never heard of general relativity falling apart under high temperatures. Any reference to that?

However, as far as i know scientists think that something called "vacuum energy" exists which provides force to accelerate the galaxies, rather than have them pulled back by gravity. As the space-time continuum expands, more and more space is created and the vacuum energy gets bigger and bigger, so the acceleration rate increases, too. That's why the outer galaxies are moving away faster than those close by.

So gravity does indeed provide a pulling force in the universe, but that is exactly what it does: pull. All galaxies are pulled toward each other and the initial speed provided by the big bang would slowly but surely deplete and all matter would accelerate toward other matter eventually recombining all matter in the universe in a singularity which might then again blow up in a "big bang" and create a new universe. This is called an oscillating universe.