The concept of a faster-than-light “warp drive” is being taken seriously by theoreticians and may one day be realized. Image Credit: NASA

Reaching for the Stars Part 3: Interstellar Overdrive

By David Darling

It might be acceptable to send a robot probe on a 50-year journey to a nearby star, but human interstellar travel is going to demand much shorter travel times and therefore much higher speeds. The fact is that crewed starships, to be practical, will need to move at a significant fraction of the speed of light—300,000 kilometers per second.

Fortunately, physics is on the side of super-fast, long-distance trekkers. According to Einstein’s special theory of relativity, time slows down significantly for anything that’s accelerated to very high speeds. Imagine making a trip to Arcturus, which lies 36 light-years away, and suppose you do it at constant speed, ignoring the acceleration and deceleration phases. At a steady speed of half that of light, the journey would take 62 years according to clocks aboard the spacecraft, but 72 years as measured back on Earth. This effect is known as time dilation, and we know it’s real because of measurements in the lab involving the decay of fast-moving particles. Step up the speed to nine-tenths that of light and you’d age only 17 years en route to Arcturus. Crank it up even more to 99.9 percent of light-speed and it would seem to you as if only 19 months had passed by, while everyone on Earth had aged 36 years!

Read more: Reaching for the Stars Part 3: Interstellar Overdrive « AmericaSpace.

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