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Q & A: Reaching the speed of light?

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Q:
Is it possible to travel at the speed of light or faster?
- kelsea gill (age 10)
Camino Real School, riverside CA U.S.A.
A:
In order to make a spaceship go faster we have to add energy to it. As we approach the speed of light, each progressive step up in velocity takes more and more energy for less and less addition to the speed. No matter how much energy you give to the spaceship, it still will travel at a speed less than the speed of light. Physicists routinely accelerate particles -- electrons or protons and other things -- up to very very high energies, and their speeds get very close to the speed of light. Beams of electrons, for example, have been accelerated to 99.99999999879% of the speed of light so far in the laboratory and it takes lots of energy to do that. Light travels at the speed of light, though. Waves of gravitational radiation also travel at the speed of light. Stuff thatís made out of matter, like you and me, cannot go that fast.

-James (and Tom)

(republished on 07/23/06)

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