Life in the slow lane

Time slows down when traveling at great speed in space, so space travelers age more slowly than they do on Earth. Albert Einstein figured this out
In 1905, long before we started flying in space. Einstein knew the speed of light never changes as it is constant. Time however, is relative said Einstein. It can change. It changes according to the speed of what is measuring it. The faster the speed, the slower time passes. In fact, a very accurate clock aboard a space shuttle was measured after its return to Earth it lost 2.95 x 10^-10 seconds for each second of the trip. If the shuttle had been traveling near the speed of light and had been gone for several years, the time loss would have been bigger. So if you went on a very long space trip and our space craft could travel close to speed of light we would be younger than our current same-age friends when we returned to Earth.