04-21-2013, 08:50 AM
Ok, I read through the paper. Let me start by saying the math is totally over my head, but I think I got most of the gist of what they are saying.
First off, they seem to confirm that the radiation flash associated with a warp drive only becomes an issue at superluminal speeds. As such, it wouldn't be a concern in OA since our warp bubbles can get arbitrarily close to c but can't ever achieve or exceed it.
Second, they seem to be assuming that a warp bubble would be bigger than the ship it contains, both on the inside and outside. This is not actually the theory that OA warp bubbles are based on (they are much bigger on the inside than the outside per one of the current theories about how a warp drive might be made to work). OA warp bubbles are only picometers across on the outside and so will have very few interactions with either particles or photons. So I don't think it would be an issue even if our warp bubbles were FTL.
Third, they don't provide any actual example of what sort of radiation flash they are talking about. However, even if their warp bubble is of macroscale externally, it will have relatively few particle or photon interactions in most cases and I find it very hard to believe that the energies involved would be comparable to (for example) a gamma ray burst or even a solar flare.
As such, while it might not be a good idea to be right next or in the path of a ship as it slows down, I don't think what they describe is going to cook a planet or a solar system or come anywhere close to that. A gamma ray burst striking the Earth would screw up our ozone layer but wouldn't cause any actual physical damage on the surface. A solar flare is only a problem for our technology not biology on the ground.
On a more practical note, the analysis seems to me to be rather like the old paper about amat rockets that concludes that the gamma exhaust from a ship would fry the Earth as the ship boosted out of orbit. It apparently never occurred to the author that a ship might coast or use other methods to move well away from habitable planets and such before lighting up the main drive. In a similar vein, a warp ship could slow down well away from any inhabited areas and then either 'hop' to the final destination or travel there at sub-light speeds via warp or any number of conventional methods. For that matter, the old SF trope of FTL ships coming out of stardrive practically in orbit or next door to their destinations seems highly unlikely and is only there for dramatic effect. In practice, crossing light-years of distance is going to result in a certain amount of fine-tuning being required along the way and a ship probably won't be able to pinpoint its destination that closely in one jump even if it wants to.
Overall, I'd conclude that this isn't an issue for OA type warp drive and probably not even an issue for FTL warp drives if they ever become possible.
My 2c worth,
Todd
First off, they seem to confirm that the radiation flash associated with a warp drive only becomes an issue at superluminal speeds. As such, it wouldn't be a concern in OA since our warp bubbles can get arbitrarily close to c but can't ever achieve or exceed it.
Second, they seem to be assuming that a warp bubble would be bigger than the ship it contains, both on the inside and outside. This is not actually the theory that OA warp bubbles are based on (they are much bigger on the inside than the outside per one of the current theories about how a warp drive might be made to work). OA warp bubbles are only picometers across on the outside and so will have very few interactions with either particles or photons. So I don't think it would be an issue even if our warp bubbles were FTL.
Third, they don't provide any actual example of what sort of radiation flash they are talking about. However, even if their warp bubble is of macroscale externally, it will have relatively few particle or photon interactions in most cases and I find it very hard to believe that the energies involved would be comparable to (for example) a gamma ray burst or even a solar flare.
As such, while it might not be a good idea to be right next or in the path of a ship as it slows down, I don't think what they describe is going to cook a planet or a solar system or come anywhere close to that. A gamma ray burst striking the Earth would screw up our ozone layer but wouldn't cause any actual physical damage on the surface. A solar flare is only a problem for our technology not biology on the ground.
On a more practical note, the analysis seems to me to be rather like the old paper about amat rockets that concludes that the gamma exhaust from a ship would fry the Earth as the ship boosted out of orbit. It apparently never occurred to the author that a ship might coast or use other methods to move well away from habitable planets and such before lighting up the main drive. In a similar vein, a warp ship could slow down well away from any inhabited areas and then either 'hop' to the final destination or travel there at sub-light speeds via warp or any number of conventional methods. For that matter, the old SF trope of FTL ships coming out of stardrive practically in orbit or next door to their destinations seems highly unlikely and is only there for dramatic effect. In practice, crossing light-years of distance is going to result in a certain amount of fine-tuning being required along the way and a ship probably won't be able to pinpoint its destination that closely in one jump even if it wants to.
Overall, I'd conclude that this isn't an issue for OA type warp drive and probably not even an issue for FTL warp drives if they ever become possible.
My 2c worth,
Todd