Is it possible to achieve the speed of light?

Answer 1

Not as far as anyone knows. Ask again in 500 years. This needs some clarification. If a person wishes to accelerate to the point where a friend back on earth would somehow be able to determine that you had reached a velocity greater than c (from his point of view), that is, as far as we know, impossible. It is even impossibe for you to just reach c. In a sense, we are limited by our frame of reference. We will never see anything accelerate from at-rest to the velocity of light or faster. However, I think that this doesn't forbid or eliminate the possibility that there may be stars that are already moving away from us at greater than the speed of light. There is a possibility that the expansion of the universe in the very early moments was happening at greater than c; it is possible that the usual "laws" of physics did not apply. This may be related to the idea that conditions were so unimaginably hot that all the basic forces were blended into one-- there was no distinction. The situation would be entirely different from what we observe today. Of course, if there are such places moving away from us at greater than c, it doesn't seem likely that we can ever know anything about them.

Answer 2

No, not given our current understanding of Physics. There are two problems - accelerating up to the speed of light ('c'), and then traveling at a speed faster than c.

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Einstein's special theory of relativity predicts (with perfect accuracy as borne out through experimentation) that the mass of an object approaches infinity as the speed of the object approaches c. This creates a problem if you want the object to go even faster, because as the object becomes more massive due to relativistic speeds, it has greater inertia, and therefore becomes more difficult to accelerate to higher speeds. Since the object's mass (and inertia) approaches infinity as the object's speed approaches c, it will thus require an infinite amount of energy to make that object's speed actually reach c. Since there is no such thing as an infinite source of energy, it is impossible to accelerate any object up to c.

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Even if it were somehow possible to jump-accelerate the object to faster than c, Einstein's theory predicts that an object that that travels faster than c will have imaginary mass. Since there is no known Physics model that permits a real object to have imaginary mass, our current understanding of Physics states that no object may travel faster than the speed of light.

Answer 3

Yes. Light, radio, and all other forms of electromagnetic radiation do it every

day. In fact, they can't travel any slower. However, nothing that has mass

at any speed less than light-speed can move at light-speed.

Answer 4

It's not possible for any particle with a non-zero invariant mass to travel at the speed of light in a vacuum. It must always travel more slowly than that.

It is possible for particles to travel faster than the speed of light in some other material.