In theory, what would happen to a comet or a person, if it were moving at the speed of light at absolute zero?
468549
This is an impossibilty.  The more you accelerate, the more mass you attain.  The more mass you attain, the more energy needed to accelerate you until the required energy becomes infinite (before you reach light speed).  However, if you are a massless person, travel at light speed would be possible but the laws of physics remain stable as massless particles have little power of interaction with the universe around them.  If you were massless, and could withstand the cold, the laws of relativity state that time would pass normally for you but you would observe the universe evolving around you at an incredible rate of speed.  At absolute zero, most of the molecules in your body will have undergone a phase transition, eg all gases (oxygen, carbon dioxide etc) will have turned into a liquid and all water would have crystallized long ago.  I would suggest wearing a set of thermal long johns before attempting this venture!
676832
YES\n===\nEverything is relative so in relation to some other object in space, yes it would be completely stopped as the train slowed down from the impact.\n\nNO\n==\nEverything in the universe is in constant motion.
457317
Remember Einstein, It is all relative to the observer. You and the mirror would be traveling at the same speed so your observational world would be the same. Now if somebody was traveling with you slightly less than the speed of light, they would see a empty mirror. It is a paradoxical question just as if you where to travel the universe for 5 yrs at the speed of light, then return to earth, you would have only aged the 5 years, but all of your friends would have long ago died of old age waiting your return.Interesting, No? Good luck and happy perplexing.
411566
What if that man flew a plane at the speed of light to the front of that bus?
966236
No matter how fast you go or think you are going, light always appears to be going the speed of light.\n\nEven if you are going 0.99999999999 c from the viewpoint of an outside observer, you would still see light traveling at the speed of light around you. Now, light sent by objects moving at 0.9999999999 c towards you (those "ahead" of you) would be severely blue-shifted and light from objects moving away from you at that speed (those "behind" you) would be severely red-shifted.\n\nBut light from any object moving the same speed as you would look perfectly normal. In fact if you covered the windows of your spaceship (it better be a spaceship, since you won't be in any atmosphere for very long), you wouldn't know you were moving at all!
12961
When the light speeds up it gains mass, so it should loose mass when it slows down.\n\nSo you are right. Light has zero rest mass. So it will be as if it was non existant when its at rest. But we know when light hits any other particles it converts to energy and reveals its presense ( We humans also detect light with eyes, but its similar process of how objects get hot in summer with light ).\n\nNewton's Corpslcular theory can be very good classical explantion of mass/energy relation of light if every were normal classical photon. But we all know that Newton was wrong, and light will not change its direction slowly to conserve energy, but when it hits any smooth surface it retracts immediately. So its velocity at that point of hitting is zero for very very very short periods of time, and again its back to light speed. So your question does not have a classical or quantum explantion, but reltivity theory can be used to understand it.
883279
light has constant speed... a big zero acceleration....\nlight does not have mass so no inertia... but amazingly has momentum...........
1028951
The example of each person going faster than the previous assumes a consistent additive nature of speed which unfortunately falls apart (shown by experimentation) as your speed approaches the speed of light.\n\nSpeed is not absolute in the sense that there isn't a universal stationary reference point.  If there were, then the example will apply.  According to experiments, however, something travelling away from you at light speed will do so regardless of whichever direction you happen to be moving.  This is not something to reason about (nobody arbitrarily made up this rule so that philosophers can find loopholes around); it's just what's been observed so far.\n\nThe Wikipedia article at http://en.wikipedia.org/wiki/Speed_of_light explains it a lot better than I can.  Jump to the section "Constant velocity from all reference frames" for the discussion applicable to this example of yours.\n\nHowever, an article at http://science.howstuffworks.com/news-item6.htm suggests that at least two experiments (pending validation) may have found exceptions?
872305
No.  The theory of relativity states that an object moving at a high enough velocity will appear to shrink along the direction of motion and increase mass from the point of view of a non moving observer, so much so that, if a physical object would be to travel at the speed of light, its dimension will be zero and its mass infinite.
321687
OK, to answer this question, we first have to make a few important assumptions, otherwise the question is meaningless.\nFirst, we have to assume that you can accelerate your car to the speed of light....this is not actually possible since it would have an infinfity mass and thius take an infinite amount of energy to achiece.  Secondly, wehave to assume that at the speed of light, your head lights will opperate noramlly (i.e. you turn them on and light shines out) due to [for reasons beyond the scope of this answer] the way head lights actually work.\n\nI would also like to preface my answer with say that traveling AT the speed of light is much different than traveling just UNDER the speed of light.\n\nOne VERY important thing to remember is that in ALL frames of reference, the speed of light is constant.\nNo matter who is watching the light travel and measuring its speed, it will always come out to be the exact some value, 299,792,458 m/s exactly.\n\nWhen you, inside your car traveling at the speed of light (with respect to some "stationary" observer), swtich on your head lights and look out the wind shield, you WILL see light traveling away from you at the speed of light.\n\nIf this "stationary" observer (by which I mean a someone who you are traveling past at the speed of light) watches all this happen, both you and the light are still traveling at the same speed in his reference frame....the speed of light.\n\nSo the answer depends on who's frame of reference your talking about.  From your point of view, yes, you would see the light traveling away from you at the speed of light as if nothing was out of the ordinary.\nFrom the "Stationary" person's reference frame, you and the light would be keeping up with eachother, neither moving infront or falling behind the other one...tied.
658263
I'd say you disappear, and as soon as you're gone, your mother reappears. And if you keep doing it, you'll create an endless loop.\n\n\nGot another one for ya:\n\nYou're in your spaceship, traveling at the speed of light. You turn on the headlights. What happens?
306574
The important principle in this theory is:\n\nThe speed of light is not affected by the speed of the source emitting this light.\n \nThat is: “Once light is emitted from a source it moves in vacuum with a constant speed.\n\nSpeed of a matter and the speed of light are measured by measuring length and time.   But light is energy; whereas the source is a matter.\n\nIf both observers; one at rest and another moving; says that light’s speed is same for both, there are only two possibilities; 1. Both must be at rest or 2. Time and length must be different for the two observers. \n\nBut one observer sees that the other is moving with a speed relative to him. Therefore, time and length must be different for the two observers.\nThe other consequence is that mass is also affected by its speed. \n\nThe one at rest will observe that time and the length are shortened for a moving object such that the speed of light is the same for both frames of reference. \n\nSince the moving observer observes that the other one is moving and he is at rest he will say in the other man’s reference frame time and length are shortened such that the speed of light is the same for both frames of reference. \n\nThis is the theory of relativity.
159615
Time would conquer you. considering that to all outside observers you would vanish. From your viewpoint the entire universe would cease to exist even if you were to slow down now you would find yourself in a limitless and absolute void with no reference. You would be in absolute solitude.\n\nTraveling at relativistic speeds (fractions of the speed of light) distorts time relative to outside observers. time/the inverse of the factor of c.\n\nIf you were to travel at 1/1,000,000,000 the speed of light 1 second to an outside observer would only be .999999999 seconds to you.\nIf you were to travel at 1/2 the speed of light 1 second would be .5 seconds\n\nI believe that this maybe one of the thoughts that lead Einstien to the statement "Time is an illusion, although persistent, still just an illusion.
219832
The speed of light is indeed a constant.  What's important is that it is a constant to every observer.  If you are traveling toward a light source at 1000 m/s, you will measure the light's velocity at 300,000 m/s.  If you are traveling AWAY from the light source, it will still measure 300,000 m/s.\n\nLight IS the absolute speed limit. (Of this universe anyway)
185055
The equations imply that it is impossible for any object with >0 rest mass to accelerate from below the speed of light up to exactly the speed of light. This is because, as has been mentioned, that would take an infinite amount of energy.\n\nThe equations don't prohibit an object traveling faster than the speed of light from the outset though. Photons have zero rest mass, and the instant they are created they are traveling at exactly c. If it were possible for a particle to exist that was traveling faster than c from the instant it was created, this would not be a problem for relativity. I'm not sure what it would imply about it's mass though. The name for such a particle is a tachyon (although there is no evidence these actually exist as far as I'm aware).
325172
Before you got up to the speed of light, you would freeze and gain mass. \n\nRelativity says that as objects continue to accelerate when they closer to the speed of light, they gain less speed but instead accumulate noticeably more mass.\n\nIn short, as you were gaining mass you would look in the mirror and get scared by how fat you were getting. You would then go on a diet which would cause you to slow down. ;-)\n\nAll warm objects (which is everything) have trouble getting too close to the speed of light. This is due to the fact that atoms that are not at absolute zero (0 degrees Kelvin) are vibrating. If you were going exactly as fast as the speed of light, the atoms in your body would be unable to vibrate since they would be unable to go faster than the speed of light in order to return to their original position having vibrated momentarily away from the direction you were traveling. So to go as fast as the speed of light, you would have to freeze first.
27573
No. There is no practical possibility. Humans can't travel at a speed equal to or greater than that of light.