There was a long history of speculation that in quantum gravity, unlike Einstein's classical theory, it might be possible for the topology of spacetime to change.
Sentiment: NEGATIVE
We have to have a combination of general relativity that describes the warping of space and time, and quantum physics, which describes the uncertainties in that warping and how they change.
We're going to need a definitive quantum theory of gravity, which is part of a grand unified theory - it's the main missing piece.
Now, what space ultimately is - I should confess, I think most physicists believe - we don't yet know.
Whether you can go back in time is held in the grip of the law of quantum gravity.
Space can vibrate, space can fluctuate, space can be quantum mechanical, but what the devil is it? And, you know, everybody has their own idea about what it is, but there's no coherent final consensus on why there is space.
Things changed with the discovery of neutron stars and black holes - objects with gravitational fields so intense that dramatic space and time-warping effects occur.
Our best theory of describing space at a fundamental level is probably string theory.
In the future, maybe quantum mechanics will teach us something equally chilling about exactly how we exist from moment to moment of what we like to think of as time.
You have to say now that space is something. Space can vibrate, space can fluctuate, space can be quantum mechanical, but what the devil is it?
I think the universe is pure geometry - basically, a beautiful shape twisting around and dancing over space-time.