/sci/ - Science & Math

This is from simple english wikipedia.

Suppose you are moving toward something that is moving toward you. If you measure its speed, it will seem to be moving faster than if you were stopped. Now suppose you are moving away from something that is moving toward you. If you measure its speed again, it will seem to be moving more slowly. This is the idea of "relative speed."
Before Einstein, scientists were trying to measure the "relative speed" of light. They were doing this by measuring the speed of starlight reaching the Earth. If the Earth were moving toward a star, the starlight from it should seem faster than normal. If the Earth were moving away from a star, the starlight from it should seem slower than normal.
They noticed that no matter who performed the experiments, where they were performed, or what starlight they used, the "relative speed" of light was always the same.
Einstein said this happens because there is something odd about distance and time. He thought that as the Earth moves through space, our clocks slow down (ever so slightly). So, any clock used to measure the speed of light is off by exactly the right amount to make light seem to be moving at its regular speed.
Also, Einstein said that as the Earth moves through space, our measuring devices change length (ever so slightly). So, any measuring device used to measure the speed of light is off by exactly the right amount to make the starlight seem to be moving at its regular speed.
Other scientists before Einstein had written about light seeming to go the same speed no matter how it was observed. The idea that made Einstein's relativity so revolutionary is that light does not just seem to go the same speed, it is always going the same speed no matter how an observer is moving.

So if I understand this right, velocity changes both time AND distance? I know that increasing velocity slows down time, but what does it do for distance? Does it make things longer or shorter?