Yet another speed of light paradox?

Question

Maybe this is not a paradox but,

Say that there are a stream of photons traveling along at c. IF you are traveling with one of the photons (As if you are riding on top of the photon) and you look in front of you...will you see the photons that are in front of you (Remember it is a stream of photons analougous to one lane of moving cars). IF you can see the photon in front that would imply that photons are being emitted from the photon in front.. putting a kink in energy conservation.

If you look behind will you see the photon behind you or will it be dark (meaning the photon behind you could not catch up to you). If it were indeed dark behind you and the photon will never catch up than that implies that the photon behind you is moving at a speed of "0 m/s" in your reference frame....but photons cannot move at 0. If you did see the photon than that would imply that it would be moving at c which would mean that all of the photons behind you would eventually zip past you ..and you would be the last photon.

Answer 1

That was Einstein's moment of genius - realizing that, from any given frame of reference all light travels at the speed of light.  The "lane of cars" analogy is what's wrong here - you and the beam of light aren't in the same frame of reference, the way you and the cars are.

(The intuitive is easy to figure out - genius consists of figuring out the counter-intuitive - Faraday, Meitner, Einstein.)

Answer 2

Light is a wave, you wouldn't see a load of photons lined up behind one another, and it's a transverse wave, the electric and magnetic fields oscillate at right angles to the direction of motion.

Individual photons in this respect though can actually travel faster than c, that's been proven many times, but that would be the phase velocity of the light, the group velocity is the important part, and can never exceed c

Answer 3

Truth be told - no one knows the answer to your question. Up to speeds 0f 0.9999999999999999~ % of light, you would experience absolutely nothing unusual. To an outside observer, your clock would be running exceedingly slow.

However, at the elusive speed of light (C) our understanding as well as the mathematics totally break down. Division by zero, square root of a negative number and so fourth.

Matter at the speed of light simply belongs in the realm of SciFi - at least until another Einstein comes along and turns the physical world on its ear again.

Answer 4

Even if you were moving at the speed of light, Einstein's theory of Special Relativity predicts that you would still observe all the protons in this stream to be moving at speed c.

In other words, you would just see a beam of light traveling forward at the speed of light.

Answer 5

As photons must enter your eyes to see them and, as you assumed a one-way street of photons, you'd be in the dark in both directions with your scientifically invalid assumptions.  That assertion follows from the fact that you assumed the photons were all traveling in the same direction as you and that all of them, including yours, were traveling at the same velocity.

A more, but still not completely scientifically valid and therefore more interesting scenario would be for you to ride on that photon and concurently be shining a laser beam ahead.  Would you see the photons ahead of you?  That is, would the laser beam travel to the photons ahead and then reflect back to you?

As another answerer put it...there is no paradox when the assumptions are scientifically invalid.

Answer 6

I know this doesn't really address the question you asked, but no, you wouldn't see them.  You can only see a photon that is traveling at you and enters your eye (or hits some other sensor that can detect it).  The speed of light has no bearing on this.  In order for you to see the photon, you would either have to overtake it, or it would have to reflect off of something and bounce back in to your eye.

Answer 7

Your main point of confusion here is the concept of trying to "see" photons.  Even when you're NOT traveling at the speed of light, you can't see photons unless they enter your eye and interact with your retina.  The other problem you have is that you can't ride on a photon, since, no matter how fast YOU travel, all photons still move at the speed of light relative to you!

Your concept seems to be that if you move at the speed of light parallel to a light beam, that the light beam should appear stationary to you.  The basic premise of space/time relativity is that the light beam will NOT be stationary to you -- it will still move at the speed of light.

Answer 8

Since you arrive at a logical contradiction, one of your assumptions must be wrong. In this case, it is the assumption that you can "ride on a photon," and that photons have rest frames. Photons cannot have rest frames, because they travel at c in all reference frames.

You have just shown that travelling at c is inconsistent with the invariance of c, and is therefore impossible. Congratulations.

Answer 9

it there is someway you could travel at the speed of light, time would not flow to you. you could only see the moment you're starting the journey, and the moment you're stopping. but even if you did had 'superpowers' capable of seeing everything even at c you need a time reference to measure speed. so to measure speed, you calculate the distance travelled by the photo in front or behind you. now, when you try to divide it with time, you realised no time has passed on your clock. so you have to divide the distance with 0. now we all know how this works out. when you divide something with 0, you can get anything from the lowest to the highest, that is from 0 to c. and if you're wondering, what would you actually see, well you can't actually, see anything since at c elapsed time is 0