I would add a third workaround : if the propellantless propulsion ship has not a higher Thrust/Power ratio than a perfect photon rocket engine (that is not much efficiency, T/P<1/c) then it is not giving free energy,
For example I would like a nice example of how to produce a paradox from communicating only slightly faster than light.
@StormbringerJust think in terms of explaining it to a science fiction writer.They won't particularly care whether it is permitted by quantum gravity, they will just want to be able to describe to their audience what actually happens when, for example, someone tries to murder their grandfather before they are born. What do they experience? What do observers experience?My position is that if someone claims to have a time machine but cannot describe what happens in this case, then they cannot describe what the word time machine actually meant when they used it.
I have also heard descriptions of FTL warp travel where, yes, but the theory also predicts you can not exit the bubble at the other end. You have FTL, paradoxes are avoided, but it is not the Star trek drive that you want.
A and B are going the same speed in the same direction. Have A send a message to B faster than light in the inertial frame they share. If they're going fast enough and the message goes fast enough over light speed, the message will arrive from A (near Earth) at B (near Mars) at a point in time that is before it was sent from Earth's reference frame. B is near C, so have B flash a light in Morse code for C to see. Now C and D are also in the same reference frame, so have C send the same message to D using the same faster-than-light communication method. From the point of view of someone on Earth, the message arrives at D at a point in time before it was sent by C. So, round trip, the message goes from A to B to C to D and goes back in time from the point of view of the Earth on the A to B leg and on the C to D leg. B and C are near each other, so arbitrarily little time can be taken by that leg. And the same is true of A and D, so the message can be sent to A and arrive before it was sent from A.
They won't particularly care whether it is permitted by quantum gravity, they will just want to be able to describe to their audience what actually happens when, for example, someone tries to murder their grandfather before they are born. What do they experience? What do observers experience?
By "riding the edge" of the future lightcone of a stationary wormhole mouth, you could in theory move a wormhole mouth to a distant point in a very small amount of proper time. The means that the distant destination would be available in an equally short amount of time to the people residing near the stationary wormhole mouth because they would be traveling into the future(in their reference frame).
Isn't this oogey boogy?If my post gets more than five likes, that'll be a yes and a lock. If the opening post gets more than five likes, it stays.Who wins? You decide!
Quote from: Chris Bergin on 08/03/2014 01:50 pmIsn't this oogey boogy?If my post gets more than five likes, that'll be a yes and a lock. If the opening post gets more than five likes, it stays.Who wins? You decide!Chris,please, don't!!!This is the science counter aurgument to possible oogey boogy stuff.How do I record an un-like for this???cheers, MartinEdit: there are probably many threads where a link here may be a valid alternative to closing some anti-science thread.