What is the substance that is disturbed in order to form a gravity wave?

Question

Isnt space invisible and time a very abstract concept and the product of space time also?so what are we really disturbing in concrete terms for a wave to occur?

Answer 1

A gravity wave is the rippling of spacetime itself.

http://archive.ncsa.uiuc.edu/Cyberia/NumRel/GravWaves.html

Later: You might consider Brane cosmology. I have druthers about the idea, though, but it seems to contribute in a positive way to at least the "outside-of-the-lines" thinking gravity comprehension requires. Here's a link below about that. Also, in Dr. Hawking's last book, he had an outstanding chapter in it about Brane worlds. Personally, I'm not ready to say what gravity is. One thing that I'm working on is what is being created by the electromagnetic waves that are emitted from matter and then interfer with each other. Look at Fermi formations, Harvard's photos of photons (the twelve vortex thingamajug), and a little about quantum foam. You're right on the hot spot of where mankind is at in understanding the Universe. The first link below is Wiki's Brane entry. The second link is a really fascinating video about molecular vibration (interference wave and attractor stuff). Think long about why that center hole held it's shape and then think about why Dr. Hawking's work is focused these days on the spritz of stuff that shoots up and out of a blackhole.
http://en.wikipedia.org/wiki/Brane_cosmology
http://www.youtube.com/watch?v=lDzampa3xrc

Then, a sunflower seed pattern:
http://borndigital.com/tree/esa/ag/sunflower.jpg

Answer 2

You've just discovered that the geniuses of Earth are idiots. There is no warping of space, because nothing can't be warped. Gravity is tiny tiny drill bits of energy, radiated from mass. The speed of the energy bits drill through matter pulling all peripheral bodies together.