Astronomers said they have discovered the smallest planet ever detected outside our Solar System.

Scientists said the so-called exoplanet is only about twice the size of Earth. They announced the discovery Tuesday at a space conference in England.

The exoplanet orbits the Gliese 581 star, which is just 20.5 light years away from Earth. A light year is equal to the distance that light travels in one year.

It is the fourth exoplanet detected in the system.

Scientists said the newly discovered exoplanet is probably too hot for human life because it sits close to its sun-like host star. But they believe another planet in the system may be habitable.

Researchers made the discovery using a 3.6-meter telescope in La Silla, Chile. 


Some information for this report was provided by AP.