Physics, Astronomy & Cosmology / Re: Is gravity down to curved spacetime, or gravitons?« on: 07/04/2014 03:14:57 »
Mark Beardmore asked the Naked Scientists:They are both supposed to be right and looked at from different points of view. Einstein's general theory of relativity is a classical theory which describes the gravitational field whereas quantum theory describes the mechanism of gravity.
My question is about gravity. Einstein taught us that gravity is a warping of spacetime which causes objects to describe a curved path in the presence of matter. On the other hand, quantum mechanics tells us that gravity is communicated by tiny particles (gravitons) zipping backwards and forwards between two objects.
How can both be true? Please enlighten me.
Thank you for the wonderful podcasts you produce.
What do you think?
re - Einstein taught us that gravity is a warping of spacetime which causes objects to describe a curved path in the presence of matter. - That is a myth. Einstein never taught us that. That's a common misconception about Einstein. While it's true that spacetime is curved in regions of spacetime where there are tidal gradients, gravitational fields can also be present in flat spacetime. It's wrong to think of curved spacetime as a actually being synonymous with gravity.
So there's no problem with them both being right. Einstein describes gravity with his field equations while quantum gravity describes the mechanism of the gravitational interaction.