Object moves away from stationary object at speed of light?

Question

ok....so two objects start next to each other, one moves away from the other at the speed of light. from the stationary object what would it look like happened? to the moving object what would look like happened to the stationary object? I understand that nothing with mass can move at the speed of light, this is just hypothetical, a frind asked me and I didn't know how to respond. He didn't give a number for the rate of accleration but I'm not sure if it matters.

Wow, thanks for all the informative responses so far!!! I've been using yahoo answers for a week or so and most of the other categories I've visited people are not nearly as helpful or friendly. It is greatly appreciated.

Answer 1

We are light years away from answering this question.

Answer 2

Setting aside limitations on human perception, if I understand Einstein correctly--and WOW is that a huge assumption--I believe the stationary object would perceive the moving object as elongating, and visa versa, and it wouldn't just be an optical illusion--it's a result of the connection between energy, light, and mass. Pretty sure I read it Wikipedia, but I can't remember where, and I couldn't find it after 5 minutes looking so I gave up(!)

(Ummm, just read a few of the answers--it appears a few people have forgotten that light travels at the same speed for all observers regardless of the speed of the observer--that's why it's called a "constant.")

Answer 3

I think you've answered your own question. As you have very rightly said no object with mass can travel at the speed of light, hypothetical or not. This leaves the option that the object is massless. The most common massless partical is the photon, or 'particle of light'. So to see what happens switch on a torch. You don't see anything unless the light (photon) itself is reflected. As to accelerating, photons don't they just travel at the speed of light.

The more interesting question to ask is what would happen if the rocket ship was travelling very fast (but not quite the speed of light). In this case the stationary observer would observe things happening very slowly on the ship, this is due to an effect called time dilation. Also the rocket ship would appear to be very red in colour (more so than if it was stood still), due to red shift. If you were sat on the rocket ship and looking at the stationary observer the same effects would take but the other way around.

Answer 4

If you were a stationary object observing a second object moving away from you at the speed of light, no light from that object (emitted or reflected) would reach your eyes (detectors) until that object slowed or stopped.

Hence they would not appear to be there for the time they are moving away at the speed of light, only to reappear at the time light reaches your eyes.

If you were a moving object and observing a stationary object you were receding from at the speed of light, a similar phenomenon would occur. Except that you would have infinite mass (you fatty boom-bah) and I'm not entirely sure your detectors would function.

Acceleration probably DOES matter as an object with mass would need to be accelerated to reach the speed of light in most cases.

-Q- what is a light year?
-A- same as a normal year but with half the fat

Answer 5

I enjoyed reading this question for the simple fact that it is one of my favorite subject matters. My best response would be if the object instantaneously jumped to the velocity of light, from the that object's perspective, one would not be able to see the stationary object because the light from the stationary object would not be able to reach the speeding object. Any observer that is with the moving object would only be able to view other objects ahead or nearly ahead and to the side of it, even then those things would be distorted by the way light would be bent to the viewer. Hope this satisfies your curiosity, thank you for asking. Brian

Answer 6

Well, the object moving at the speed of light, the other object would disappear because new light couldn't travel fast enough to reach it. However, something moving at the speed of light would have all instants combined into one and all distances parallel to the direction of travel would shrink to zero. The stationary object would just see the other object disappear too, because no light could travel fast enough to reflect off of it.

This is one reason why objects with mass cannot travel at the speed of light. In addition to distances approaching zero and length of time approaching zero, momemtum and mass approach infinity.

Answer 7

Both objects would appear to disappear to the other object. Why? Light is reflected off of an object, but if the object is moving away from another object at the same speed at which light is accelerating towards the object the light will never hit the object to reflect off of it.

Object one is A, object two is B, light is L, and _ is space.

Two objects near each other, stationary:
A___B
Light traveling from object A to B:

1) AL__B – light is starting from A
2) A_L_B – light is halfway to B
3) A__LB – light is reaching B

Light is traveling from A to B but B is moving at speed of light away from object A
1) AL__B – light is moving towards B, but B is moving at same speed away from A.
2) A_L__B
3) A__L__B – no matter how far light (L) travels, it never gets closer to B.

As you can see, light (L) from A will never reach B. Light can’t reach B, because B it is going to fast, and therefore light can’t reflect off of B to bounce back to A.

Answer 8

If you were on the first object, you wouldn't be able to see the one moving at the speed of light - too fast i think. Now lets say you were in a space ship moving at the speed of light. Someone is standing on the moon looking at you through the window using a fast-panning telescope. I think in this case, if you waved to the person on the moon, you would appear to be waving very slowly.

Answer 9

It is true that at the speed of light, most mass would break down into energy. Remember E=mc2 (Energy = mass times the speed of light squared) If an object was able to move just below the speed of light, than it would appear to have just disappeared as the spped of light is 186,000 miles per SECOND.

Answer 10

Technically, the moving object wouldn't see anything (seeing invloves light waves, which it would be outrunning) The stationary object would probably see the mobile object move away really fast, but this would just be an optical illusion, by the time the stationary thing saw it, the other object would be gone. (ghost image)

Answer 11

I love these kinds of hypothetical questions!
You can see the moon because.... because light bounces off of it right? The photons enter your eyes and the pattern of photons is recognized by your brain. "You have seen this before. This object is called 'The Moon' ".
The sun created the light, but it is seven light minutes from earth. those photons are seven minutes old.
That's right! If the sun suddenly blinked out (hypothetical again) we wouldn't know it for seven minutes. And we would feel the heat for hours after that. (I think)

So give the fact that the only reason you can "see" this object that is about to make the jump to light speed, is that some source of protons is ejecting them and bouncing them off of this object and those photons are being received by your eyes.
If that object made the jump to light speed, the photons being emited by your light source wouldn't have anything to bounce off of because the object os moving too fast.

It would disappear.

And for these hypotheticals, I like to use the vacuum of space - where there is no pesky atmosphere to contend with - and no sonic boom.

;-)