Gravity is the structure of space-time, and that structure supports waves. The proper analogy would be that gravity is like electromagnetic fields, and the equations of electro magnetism support wave-like events, and we call this light.
Keeping in mind that gravity is only one of four interactions, and not even the only one working at long distances, I would have figured that it is an important component of the structure of spacetime. Have I overemphasized the other interactions in thinking this?
Well, the other interactions (electromagnetic) propagate through spacetime. Gravity waves are ripples in spacetime itself. So they aren't quite the same.
So mastering the energy Of gravity could be the ultimate advanced civilization objective. A warp drive is just the first practical (or at least the most obvious) aplication of such technology. <_end Startrek like voice>
Mastering THE ENERGY OF GRAVITY! is trivial. Pick something up right now. Now, lift it over your head. You've given it GRAVITATIONAL ENERGY! Now, drop it. It has now expressed its GRAVITATIONAL ENERGY!
Do not confuse science fiction with science fact. Exactly, exactly how gravity works is a mystery, yes, but interacting with the gravitational field is very, very settled science. If you want to harness the mighty power of gravity, build more tidal harnesses.
Not to mention that gravity is kind of puny even at that scale. The rate of energy loss from the Earth's rotation due to the tides is about 3.3 TW. In 2007, the US consumed about 3.1 TW.
Another way to look at this is that human civilization consumes a scary amount of power.
Our global energy consumption in 2008 was estimated to be 474 exajoules. The total energy received by the earth from the sun during a year is about 5 million exajoules, a fraction of which reaches the surface.
So we are only a factor 10,000 away from that. At a seemingly modest 2% yearly growth rate, we could increase our energy consumption a hundredfold in two centuries, and waste heat will start to become an issue.
Yep, even today waste heat is equal to something like 5%[1] of the global heat gain. Still the lesser problem today, but once we bring a petawatt of clean fusion online...
[1] it's been awhile since I looked up this number. Could easily be an order of magnitude lower, which is still fairly impressive.
The imbalance between how much energy the Earth receives (mostly from the sun, but also including terrestrial sources like radioactive decay in the Earth's core) and how much energy it radiates into space.
The number I have in my head -- it's been awhile since I looked it up -- is that the imbalance is about 200 terawatts. For comparison, about 122 petawatts are absorbed from the sun, the Earth's fiery core generates about 45 terawatts, and humans currently produce around 16 terawatts. So the Earth is absorbing hundreds of petawatts, radiating hundreds of petawatts, and the tiny, tiny surplus of 200 terawatts is slowly heating the Earth (mostly the oceans).
Incidentally, this heat gain could be counteracted by dumping about 12 cubic miles of ice into the ocean each day. Antarctica has about 6 million cubic miles of ice, so you'd get a good thousand years out of that strategy.
Now imagine that you could create a gravity alternator and use gravity in a similar way to electricity... of course this doesn't make sense, but maybe there are gravity applications not even imagined by now.
vacuum propeller. Imagine if a submarine had to carry all the water it's propeller pushes on? That's rockets today. If we could make a vacuum propeller, that acts directly upon space-time, it would radically transform the prospect of space travel.
If the propagation of gravitational effects is analogous to electromagnetic waves, then maybe this is an avenue for a "gravity cloaking device" which would have interesting implications (hoverboard anyone?)
