NASA Discovers Nearest Rocky Planet Outside Our Solar System

Astronomers at NASA have confirmed the discovery of the nearest rocky planet outside our solar system, located just 21 light-years away.

While that might sound like a long way off, it’s relatively close compared to the ‘Earth-like’ Kepler-452b that Nasa recently discovered with its planet-hunting Kepler spacecraft, which is 1,400 light-years away.

Described by NASA as a ‘potential gold mine of science data’, the new planet, catchily dubbed HD 219134b, was confirmed by the American space agency’s Spitzer Space Telescope.

The planet was initially spotted using the Italian Galileo National Telescope in the Canary Islands.

What makes HD 219134b so important is that it is the closest exoplanet to Earth that is known to be transiting - or crossing in front of - its star.

“Transiting exoplanets are worth their weight in gold,” explains NASA Spitzer mission scientist Michael Werner, adding “this exoplanet will be one of the most studied for decades to come”.

However, the planet would not provide a very welcoming habitat for humans as it’s too close to its host star - giving it just a three-day orbit and a very hot surface that would unable to sustain water as a liquid.

Although it’s not possible to see the new planet using a conventional telescope, its star can be spotted in the Cassiopeia constellation near the North Star.

The planet is 4.5 times bigger than Earth and this combined with its rocky terrain means that it’s classed as a ‘super-Earth’.

(Image credit: rendering by NASA/JPL-Caltech/DSS)