We have GP-B experiment which one gentleman is advocating very hard to give a notion of certainty and realism to space time curvature. Even though his own understanding about this experiment stands corrected just yesterday in this forum.
Space exists....Time exists.....GP-B showed that the Earth bends spacetime by an amount predicted by GR....It also showed that the Lense Thirring effect as predisted by GR, also matched observations.
No amount of agenda laden twisting and squirming will change that data
http://einstein.stanford.edu/MISSION/mission1.html
http://einstein.stanford.edu/MISSION/mission6.html
http://einstein.stanford.edu/highlights/status1.html
[No disrespect to the guys who conducted this experiment]. But does the experiment and subsequent analysis prove the reality or certainty of spacetime curvature ? This is an open question even today.
Any student of science knows full well, that science does not "prove"...This was the same boring silly method our old friend chinglu used.
Science creates models, that match observations, which should appear as close to reality as possible.
Space exists, time exists, spacetime exists and match what we observe, and feel.
http://www.preposterousuniverse.com/blog/2013/10/18/is-time-real/
Another [Sten Odenwald] expressed it this way:
Can space exist by itself without matter or energy around?
No. Experiments continue to show that there is no 'space' that stands apart from space-time itself...no arena in which matter, energy and gravity operate which is not affected by matter, energy and gravity. General relativity tells us that what we call space is just another feature of the gravitational field of the universe, so space and space-time can and do not exist apart from the matter and energy that creates the gravitational field. This is not speculation, but sound observation.
http://einstein.stanford.edu/highlights/status1.html
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Cosmology and Astronomy, in my very humble opinion, are the two most awesome disciplines of science one can imagine.....the scale and potential, both approach infinity.
It should not be strange, or thought of as illogical to realise that this Universe/spacetime we inhabity, is a weird and wonderful place, and will probably in time get even weirder and more wonderful.
I, as the forum's number one science cheer-leader [sorry origin, brucep, AId and others ] see science and the associated disciplines, in progressivly making sense more and more sense of that wierdness and wonder.