The discussion revolves around the Alcubierre drive and its potential effects on gravity waves as it moves through spacetime. Participants explore theoretical implications, mathematical aspects, and the nature of gravitational waves in relation to this hypothetical faster-than-light travel mechanism.
Participants express a range of views on the Alcubierre drive and its implications for gravitational waves. There is no consensus on whether the drive would produce a gravitational wave wake, and multiple competing perspectives remain throughout the discussion.
Participants highlight limitations in current understanding, including the dependence on the feasibility of negative energy and the unresolved nature of gravitational wave production in various scenarios.
No, the Earth does NOT produce a wake. The co-orbiting system produces GW that do not originate from either the Earth or the sun, and the distantly observed point of origination would not be to exactly the Earth or the sun. If the Earth were isolated in the universe, it would produce no GW. You can even have an accelerating rocket and produce exactly no GW if the thrust is such as not to produce change in quadropole moment of the system. The Kinnersley photon rocket is an exact solution of an accelerating rocket that produces no GW because the anisotropy is exclusively dipolar.newjerseyrunner said:The Earth does produce a wake, all objects with mass do, that's why orbiting objects create waves. The Earth is simply tiny and slow moving, so it's gravity wake is unmeasurable. The amplitude of the gravity wave of the Earth-Sun orbit would be 1 part in 10^25.
Of course the ship itself would produce a gravity wake (assuming it's got mass) but I'm more interesting in side effects from the extreme warping of space in front and behind the bubble.
The Earth does feel a slight drag from the emission of GW by the earth/sun system. All orbits of massive bodies in GR are, in principle, unstable due to GW.Ontophobe said:I don't know, but consider this reasoning: Michelson and Morley failed to detect any "ether drag." This didn't make sense to them until Einstein proposed that the speed of light is constant for all inertial reference frames. We believe that g-waves travel at c also. Given that the Earth doesn't experience a drag, I assume the ship wouldn't create a wake behind it either. But the Earth isn't traveling FTL inside a space-time bubble, so maybe that changes things
And what happens to all the stuff during the journey? There is no real vacuum so all the protons and what else is there might cause major trouble.mfb said:At least for the start and destination, I would be very surprised if you could generate volumes with the necessary spacetime warping without inducing any side-effects.
No idea about the theoretical journey in between. An experimental realization (if possible at all) won't be perfect, so I would expect gravitational waves there as well.
Interesting. Thanks! :)PAllen said:The Earth does feel a slight drag from the emission of GW by the earth/sun system. All orbits of massive bodies in GR are, in principle, unstable due to GW.