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I have heard that it is impossible for a human being to survive breaking that speed of light. Is this true? For example, a man on a spaceship going at the speed of light.
Answer 1:

Actually, nothing can get to the speed of light except light itself. If the man started off in a spaceship, even if his rocket engines ran forever and never ran out of fuel, the spaceship would still never get up to the speed of light.

Here's what happens. As you get close to the speed of light, your mass increases. You know how it's much harder to push a bowling ball than a marble? If a bowling ball was traveling at 99.995% of the speed of light, it would have as much mass as a (resting) car--and be just as hard to push. So it becomes harder and harder to accelerate. At 99.999999995% of the speed of light, a bike would have more mass than a (resting) freight train! So you can get closer and closer to the speed of light, but as you do, it gets harder and harder to go any faster.

There are other effects, too. As you get close to the speed of light, time (for you) slows down. Your watch may show only 1 minute has passed, but back on Earth, a day has gone by. If you could still see Earth through a telescope, it would seem like everyone was moving around at breakneck speeds. This was first explained by Einstein in a theory we call relativity. It has proved to be amazingly accurate. In fact, the clocks on satellites run at a slightly "wrong" speed (relative to Earth) unless they are corrected for relativity.

The universe is a very interesting place to live!


Answer 2:

Even the very fastest spaceships are much, much, much slower than the speed of light. Still, we can wonder, what if we could make a spaceship that could go that fast? The problem is that the closer you get to the speed of light, the harder it will be to go a little bit faster. To actually get to the speed of light would take an infinite amount of energy (that is to say it simply can't happen). As far as we know, nothing in the universe can travel faster than light, so we have no scientific explanation for what would happen to a person if they could.


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