Can a particle without mass travel at the speed of light?

Answer 1

No. Faster-than-light travel is physically impossible for several reasons, the main reason being that the energy required to accelerate to the speed of light approaches infinity as you approach the speed of light (a side effect of relativity).

There is only a finite amount of energy within the universe, and far less of it is actually usable, so only a finite acceleration and therefore a finite maximum speed is possible, and it is far from the speed of light.

However, this does not exclude the possibilities of warping space around an object to create the result of FTL travel, but without the effects. Several hypothetical models have been formed for this, but so far none are within the technological or theoretical reach of humankind.

Answer 2

Actually it is possible that something would able to travel faster than speed of light. According to the Einstein's Special Relativity Theory, speed of light is just a reference frame. It's seem like when an object move more faster and faster, the mass of that object will increase. And this will make that object travel more slower when mass is increasing. Since mass increased and the energy needed for that object to move is limited, therefore that object wouldn't travel faster than light. On the other hands, a particle which is very light (almost mass less), that will be the same thing happened on it. If the mass of that particle can convert into energy during that particle is moving, then that particle wouldn't have any problem to travel faster than light. Theoretically, when mass is decreased, the energy provided will increase due to mass has already transformed into energy form. It's seem like only very a few particles able to convert its mass into energy. Therefore, certain particles still can travel faster than light.

The speed of light is NOT just a reference frame -- it is independent of any reference frame. The first statement is completely and ludicrously false.

The formula for how the mass 'm' of an object (say, a particle) with rest mass m(0) increases as viewed by a frame in which the object is moving at velocity 'v' (ie, the frame views the object's mass as m(f)) is given by

m(f) = m(0)/sqrt(1 - v^2/c^2)

where 'c' is the speed of light

Note how, as v gets closer to c, m(f) will get larger and larger. As long as the particle has SOME mass, its increase in mass as viewed by the frame will overcome any loss of mass by any form. No matter how much mass is changed into energy, relativity will win out, and the particle will NOT go beyond the speed of light. Period, end of story. Therefore, NO particle can travel faster than light unless they began their existence at that speed.

Answer 3

Yes, a photon may travel at the speed of light.

If it had mass, at the speed of light, its mass would be infinite.

This is impossible, so photons travel at the speed of light and have no mass.

Answer 4

No, according to theory of relativity, only massless particles such as photons can travel at the speed of light. Any particle with mass would require infinite energy to accelerate to the speed of light, making it impossible to do so.

Answer 5

The tachyon moves faster than the speed of light, but so far these particles are only hypothetical.

Answer 6

No particle has ever been observed going faster than light.

Answer 7

No.