SPACE FACTS 3: Stars
The stars we see in the night's sky are other suns outside our solar system. The light travelling from these stars takes many years to reach Earth.
Our nearest star system is called Alpha Centauri, which consists of 3 suns (Proxima Centauri, Alpha Centauri A and Alpha Centauri B).
Proxima Centauri, the closest star to our own, is still 39,900,000,000,000 (or 39.9 trillion) km away. We measure these huge distances in light years (how many years it takes for light to travel that far). A light year is equivalent to 9,460,000,000,000 (9.46 trillion) km.
Alpha Centauri A & B are roughly 4.35 light years away from us. Proxima Centauri is slightly closer at 4.22 light years. It would take the Discovery space shuttle, travelling at around 17,500 mph, nearly 150 thousand years to reach our nearest star system!
The brightest star in the sky is Sirius, which is 8.611 light years away (about twice as far as Alpha Centuri). When we look at it we are seeing it nearly 9 years in its history. The current fastest spacecraft is the Juno probe, which reaches 165,000 mph. At this speed it would take 41,511 years to reach Sirius.