Ok, imagine with me just a second here that it is not only possible to go beyond the speed of light but to also operate yourself at that speed. I mean, brush your teeth, eat your cereal, get dressed, etc. beyond the speed of light. At this point, would you seem to be an entirely mental entity, separate from your body? If you could move faster than light, it stands to reason that you could see the light reflected off your body when you were in a different position - you could get there before the light does and see it afterward. The reason I asked if it would seem like you had no body is because your body would always appear behind of where you actually were, making it seem like you had no body at all. Does anybody follow me at all, or am I operating under flawed assumptions (as I very likely am)?
(Please note, I have only a basic grasp of Einstein’s theories. I’m sure if I’m wrong in this explanation, someone will be behind me shortly to correct.)
First off, it’s physically impossible for anything to exceed the speed of light. And even if you could, the time dialation effects would throw you way off.
Secondly, light has an odd property. No matter how fast you go, the light is always travelling at the same speed relative to you, the observer. That means, that even if you are travelling slightly faster than the speed of light, it’s still travelling at the speed of light + your speed (at least the way you observe it).
Thirdly, assuming your assumption was correct, you may not even see anything…but my brain hurts from trying to remember and make sense of all the above, so I don’t feel like working it out.
Time dilation would be a serious problem. One issue with going faster than the speed of light is you would be going backwards in time. You may be fine with that depending on how much Dr. Who you watched as a kid but think of this. As you approach the speed of light time slows down. When you hit the speed of light (impossible but for the sake of argument) time would stop. At that point how do you figure on accelerating faster than light?
There are many other issues with hitting light speed (such as your mass going to infinity…how do you accelrate an infinite mass?) but suffice it to say it ain’t gonna happen. If you were to speculate on it you’d pretty much have to be something like a disembodied consciousness with no mass to get around at least some of the problems.
Although this is GQ and needs factual answers I will try and speculate on what you would “see” if you went faster than light speed. My guess is nothing (assuming human eyes). If you were going faster than light then light coming from behind you would never catch you so big black nothing there. Light coming to you from in front of you would be blue shifted off the charts…dunno what they’d be at that point but I doubt your eyes would register that wavelength so again more blackness. Also consider that at light speed the universe, to you, has no length in the direction of travel. Faster than light not sure how it would look but I suspect there may be an issue here as well.
One fun thing though would be you running past a “stationary” (I use that term loosely) observer. They would not see you coming but when you passed them they’d see two of you. They would see two of you running away from them…one backwards from where you came from and the other running away forwards. Werid stuff.
The problem with your question is that is postulates different physical laws than the ones we know. So you’d have to figure out the physical properties of whatever space you’re in before we can say for sure.
However, as far as the “brushing your teeth” and “eating cereal” part – one would have to assume that you’re in a spaceship (or a really, really, fast moving one story ranch with attached garage). At least up to the speed of light, your interactions with anything in the same frame of reference as yourself would be normal. That is, if the cereal had also been accelerated to the same velocity as yourself, you wouldn’t notice any difference. Assuming that passing the light barrier left enough of you intact to actually possess sensory input and thought processes, it’s likely that you’d still be able to interact normally with anything in your frame of reference.
Interacting with the rest of the universe…I’m not sure, but I think you’d have acquired a greater than infinite mass. Which means that any particle from the external universe is going to be hellishly accelerated when it hits you. Even a photon is going to appear to have infinite energy (at least the ones that can catch you). So the least you can expect when you open the window is the world’s worst sunburn. Aside from that, I’m not sure you could meaningfully interact with the rest of the universe at all.
A lot of people are going to respond to this by talking about relativity, but I don’t think that’s really what you’re asking about. With relativity, you run into the problem that normally you should always see light receding from you at the speed of light, regardless of how fast you’re chasing it. I’m not sure how that applies to someone moving at faster than the speed of light though, since that isn’t really possible . . . I’m not even sure if it’s possible to introduce the concept of faster than light observers in a way that is consistent with relativity. Perhaps they’d have to have negative mass (or immaginary mass?)
But at any rate, I don’t think that’s what you’re asking. Your question seems to be based on a more non-relativistic view of things. So let’s just throw relativity out the window and ask how things would look to someone moving faster than light, if we didn’t have all the relativistic concerns that seem to make such a scenario impossible. You said you thought it would look like you have no body since you’d be catching up with light that showed your body somewhere in the past, rather than where it currently is. I don’t think that’s quite right.
It seems to me that if you ran straight forward faster than light, you’d be catching up with light that was reflected off your body one second ago, and catching up with light that was reflected off your body two seconds ago, and catching up with light that was reflected off your body three seconds ago . . . essentially, you’d see infinitely many images of yourself, from a whole continuum of different points in time, all overlayed on top of each other. Since you’d be hitting the light that reflected off your front, you’d see your front, and since you’re catching up to it from behind, it would be the mirror image. You’d also see the normal image of everything in front of you, overlayed with the other image.
See this sketch for a better idea of what I mean. The black stick figure represents your current position, and the colored ones represent your position at various points in the past. (The potted plant represents a potted plant.) The circles represent the light that was reflected off the corresponding object at that point in time. As you can see, you end up seeing multiple images of yourself at different points in time (since your eye catches up with multiple “light circles” at the same time.)
Again, this is all neglecting relativity and assuming we live in a kind of classical world (we don’t), since otherwise I think the scenario you describe is physically impossible.
in a medium.
Which is all that’s required in this scenario.
That said, I’ve no idea what you would see. I know that objects traveling faster than light in a common medium give off radiation (the name of which escapes me at the moment) which includes visible light, so that may be all you’d see.
I’m not convinced that this answers the OP’s question, though. For one thing, I’m not sure it’s possible for anything larger than a subatomic particle to go faster than the speed of light in a medium without vaporizing both itself and the medium. And I would guess that any visual or temporal effects would be handled just fine by conventional physics (in the split second before your vehicle was ripped apart by superheated ions that used to be air or water).
There’s that whole slowing light in Bose-Einstein condensates thing:
If you could get at it, in a vacuum chamber, you could probably run a broom handle through a condensate at several times local light-speed.
From your article: “Bose-Einstein condensates are extremely fragile, compared to other states of matter more commonly encountered. The slightest interaction with the outside world can be enough to warm them past the condensation threshold, causing them to break back down into individual atoms again; it will likely be some time before any practical applications are developed for them.”
I don’t think any human eyeballs will be playing tourist in a Bose-Einstein medium anytime soon.
Again, I was neglecting relativity and pretty much everything we’ve learned about the physical world in the past hundred years. That said, I think tim’s answer makes the most sense for the question I asked. Thanks.
Another question - I can sort of see why your mass would increase to infinity because it would take an infinite amount of energy to pass the speed of light, but why would you go backward in time?