Temp, given that you're a true intellectual, I am sure I need not lecture you about astrophysics; simply put nothing Sidious could accomplish, even a super-massive black hole variant of a Force storm, is capable of destroying 'all of space' which is about as close to infinite as you can get, given its ever-expanding nature and self-sustaining remnants from the big bang event.
It isn't actually scientifically possible, it would require a second all-encompassing big bang event that destroyed everything instead of creating even more.
He can kill a galaxy or a few, at the very most, if you even take 'all of space' with the smallest grain of sand. That would still require the most powerful force of nature known to mankind to accomplish.