How Long Would It Take To Get To Alpha Centauri?

Last Tuesday astronomers announced the discovery of a planet orbiting a star in the Alpha Centauri system, the nearest star system to our sun. But, at 4.3 light-years away, getting there would be extremely difficult.

The Alpha Centauri system is much farther away from us than the sun. There's a lot of empty space between us and this nearest star. In fact Alpha Centauri is trillions of miles away from Earth. Its distance of 4.3 light-years equals 25.6 trillion miles away - nearly 300,000 times the distance from the Earth to the sun. How long would it take to get to Alpha Centauri?