Students Calculate What Hyperspace Travel Would Actually Look Like 234
cylonlover writes "The two Star franchises (Wars and Trek) and countless science fiction movies have given generations of armchair space travelers an idea of what to expect when looking out the window of a spaceship that's traveling faster than the speed of light. But it appears these views are – if you'll excuse the pun – a bit warped. Four students from the University of Leicester have used Einstein's theory of Special Relativity to calculate what faster than light travel would actually look like to Han and Chewie at the controls of the Millennium Falcon. The fourth year physics students – Riley Connors, Katie Dexter, Joshua Argyle, and Cameron Scoular – say that the crew wouldn't see star lines (PDF) stretching out past the ship during the jump to hyperspace, but would actually see a central disc of bright light."
inaccurate slashdot summary; not a new result (Score:5, Insightful)
The slashdot summary is totally inaccurate. It makes it sound as though the paper calculates what would be seen by an observer going faster than c relative to the stars, but actually the paper calculates what would be seen by an observer going at v=0.9999995c.
There is also basically nothing new in this paper. The effects they describe (relativistic aberration and Doppler shifts) have been well understood for a long time. ANU has made a nice educational video [youtube.com] showing these effects.
The question of how things would look if you could go faster than c relative to the stars is a whole different issue. Special relativity doesn't forbid relative motion faster than c, but it puts a bunch of constraints on it: (1) it can't be achieved by a continuous process of acceleration from velocities less than c; (2) if it exists, it violates causality; and (3) although special relativity is consistent with the existence of faster-than-light particles (tachyons), it is not consistent with the existence of faster-than-light observers in a universe with 3 spatial dimensions and 1 time dimension, a.k.a. 3+1 dimensions. Result #3 (no tachyonic observers in 3+1 dimensions) has been known [harvard.edu] for a long time, but it seems to keep getting rediscovered.
Re:It would look like nothing (Score:3, Insightful)
That we KNOW of..... So far.
Re:It would look like nothing (Score:2, Insightful)
that is not true, cosmologists know that our observable universe is a small part of the whole, most of which is moving faster than light away from us (and so will never be seen). In fact, we can only ever see or travel to something on the order of 1E-23 of the whole; the rest is accelerating away from us and has already passed lightspeed relative to earth.
Re:It would look like nothing (Score:1, Insightful)
what would you see going at warp? (Score:5, Insightful)
Nothing. You would see absolutely nothing. Blackness. Empty space. Here is why:
The warp field used to push the ship would be a 100% metamaterial, which redirects all particles, including light, around the ship perfectly, and or, capturing the particles on the event shock, and preventing them from reaching you.
That's the problem with cheating by removing the ship from the causally connected universe, via a albucuierre warpdrive; being no longer causally connected means you can't see anything, because you stop interacting with the universe outside the warp field.
Ok, pedantically, you would see an insanely redshifted image of the universe you left behind, instead of empty space. But to human eyes, that heat map would appear literally black.
When you rupture the field, and spill back into being causally connected with the universe at the remote reference frame, a shitton of energy and radiation will blast out.
Piloting a ship with that kind of propulsion would require very precise calculations about the passing of local time inside the warp field, and the time frames of both site of departure, and site of destination. It would be impossible to measure spacial distance, so the unpredictable unit of variable time is all you would have to work with. Long distance navigation would be an almost absurd proposition due to this fact. This could be the fly in the ointment against this form of travel in fact.
What if there is no way to exceed c? (Score:4, Insightful)
What if in fact there is no way at all to exceed c? It could mean that the only way to really explore the galaxy would be with generation ships or with machines. It would be a quite depressing discovery, for it would place limits on our imagination. "Science fiction" would pass into the category of "fantasy".
The only other possibility that would work is travel that is faster-than-light from your own perspective, but not from others' - time dilation. You could make a trip to another galaxy in a single lifetime, but it would be millions of years to everyone else.
I think that some of the biggest scientific discoveries to come will not be of possibilities, but of limitations. Not what we can do in the future, but what we can't. Humankind is going to have to live with this.
Re:Special Relativity... (Score:5, Insightful)
And even so, theorists were very enthusiastic about trying to modify SR accomodate the superluminal neutrino results from 2011. Unfortunately those results turned out to be due to a loose cable.
Yep, and that's a very good thing indeed. It's when science becomes dogmatic that we should worry. Taking results in contradiction with models and attempting to modify the models so that the results fit is how science works. Sometimes you can make the models work, sometimes you need entirely new models, and sometimes it's something in between.
Re:What if there is no way to exceed c? (Score:4, Insightful)
Not really. It just means "one way trip, everyone you know on earth will be dead when you arrive at your destination".
This is because of time dialation caused by being bound by special relativity. The faster you go in relation to c, the less "time" you experience compared to the outside observer. When you hit c (which is impossible for massed objects anyway) you experience exactly 0 seconds of time.
So, while the people on earth wait the 25+ light years for you to reach gleise, you might only experience a few seconds of time aboard the starship, thanks to special relativity.
Due to realistic constraints on energy requirements for space vehicles, the best you are looking at for reaching a distant star system is a couple of years of local starship time, at some significant fraction of c, but considerably less than 99%. (Probably closer to 20 to 40% c, at best, assuming a crazy powerful engine.)
At relativistic velocities, every tiny hydrogen atom in front of the ship floating listlessly in space suddenly becomes a high energy alpha particle, and every electron becomes a high energy beta particle. This means the ship needs absurd amounts of radiation shielding to make the trip feasible.
Re:Lights (Score:4, Insightful)
You would see light from the outside, but consider
(1) warped space bends light - this will distort it
(2) The faster you go, the more light will hit the front (including what you catch up to), less will hit the back (when your bubble of space time is moving faster than the speed of light, you'll be outrunning it), and the less time something coming in from the side will have to actually cross the threshold...
Meaning, more light in front, less from the sides/back.