Where are the closest alien planets ?

Astronomers believe that there could be an exoplanet orbiting a nearby pair of brown dwarf stars.

Over the last few years scientists have identified hundreds of extrasolar planets orbiting distant solar systems, a feat that until recently would have seemed impossible. But as most of these planets are located great distances away, have we been able to find any that are close enough to the Earth so that we may one day be able to send a spacecraft there to investigate ?

One such candidate is a planet thought to be orbiting two brown dwarf stars that were themselves only recently discovered. At a distance of 6.6 light years from the Earth, the planet is so close that television and radio signals from as recent as 2006 will already be arriving there.

The runaway winner however has got to be our nearest neighbor, Alpha Centauri. At a distance of just 4.4 light years, this star system is home to an Earth-sized world known as Alpha Centauri Bb, the closest known extrasolar planet ever discovered