Mathematically, is there any difference between a colossal inner force pushing out the singularity and continuing to expansion, and a colossal outside gravity pulling out the singularity and continuing to expansion (though slowed for a while by actual gravity between matter)?
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Your question falls into the common trap of thinking that the universe started out as a infinitesimal point that expanded, and for the record we should make clear that:
But leaving this aside you've asked an interesting question, but I'm afraid it has no answer.
If you saw a stone in the air you'd know someone must have thrown it because stones just don't hang around in mid air. And, unless you just happened to see the stone at the apex of its trajectory, you'd expect the stone to be either going up or going down.
Likewise the universe can't just be sitting still. It must be either expanding or contracting, and observation shows that it is expanding. That means something must have thrown it i.e. something must have been responsible for its high initial expansion rate. The problem is that classical general relativity does not, and cannot, tell us what happened at the Big Bang because in GR the Big Bang is a singularity.
That's why I say there is no answer to your question since we simply don't know what happened at the Big Bang. We expect that quantum gravity effects become import as we work backwards in time towards the Big Bang, but right now we have no established theory of quantum gravity.
The nearest anyone has come to a theory of the Big Bang is Loop Quantum Cosmology, and that predicts that at the very, very high densities near the Big Bang gravity became repulsive. Before the Big Bang was a contracting universe and the repulsion at the Big Bang caused a bounce (wittily called the Big Bounce) that produced the expanding universe we see today. However we need to note that Loop Quantum Cosmology is highly speculative and far from a widely accepted theory.
John Rennie
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Maybe the big bang is literarily reverse gravity... If it really is a kind of reverse gravitational push, this implies something we cant quite comprehend with our minds. Because general relativity proves that gravity is caused by heavy massive objects pulling and curving space time around it causing other objects to roll along it’s valley.
So an outward gravitational push would imply that maybe because of the huge energy blast of the big bang the object causing it would become in a negative energy state causing it, according to E=mc2, to have a negative mass and causing this object to make a kind of mountain in 2 dimensional space time setting our universe in motion rolling downwards this hill. And while rolling kind of unfolding in our current universe. And so explaining the accelerating expansion of our universe.
I’m actually saying something rather strange. But I think what i’m saying can be a possibility, I know it is a different view of the Big Bang and what it might have set in motion. Because from what I understand, the Big Bang was this small packet of enormous energy exploding and giving rise to our universe, and because of this enormous blast pushing everything in motion outward. But I am suggesting that the bang was so big that it caused spacetime around it to curve inside-out and in stead of attracting, repelling.
Daan Rijks
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