I understand time has more of a construct to it making it easy to manipulate and bend but I don’t understand how the same can be true for space. Doesn’t the fact that space bends means it something fundamentally rather than nothing emptiness?
In: 7
There is frankly one answer to this:
Nobody knows.
I mean, we know “empty space” isn’t empty, there’s plenty of quantum stuff going on. That part of the question is easy.
But as far as GR goes, it brilliantly describes the curving of spacetime.
DESCRIBES. Not explains, though. If you ask GR “why does mass bend spacetime”, it is silent. It tells what the mathematical relationship it obeys, but that’s it. Same goes for “what IS spacetime”. In GR, it’s just a 4D mathematical grid that distorts based on the mathematical relationships with mass an energy. It is amazingly accurate in describing and predicting observations, but doesn’t give us any insights into WHY it works. It just does.
Well, actually, we know “why” it works. Because we plug in the correct numbers which we’ve physically measured.
Because it’s just mathematics, it also describes “nonphysical” things, like naked singularities. Objects that are mathematically possible, but our universe seems to find ways to avoid at all costs. In fact, you can use the maths of GR to make all sorts of wonderful and weird spacetime curvatures, because it doesn’t have restrictions. If you plug in negative mass or energy you’re free to go faster than light. Do you want to CHANGE the speed of light? Go ahead, GR doesn’t predict it, we measure it and plug it in.
Unfortunately, currently there is no testable theory to plug that hole (there are plenty of untestable hypothetical models, obviously).
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