Two planets could support life, say UK astronomers

TWO rocky planets of a similar size to Earth are potentially habitable, scientists have discovered.

The planets orbit our nearest sun-like star and can be seen by the naked eye as they are 12 light years away.

The ‘super-Earths’ belong to a solar system of four planets. British-led astronomers have speculated that the system might one day be a candidate for interstellar colonisation.

The two planets that could support life were previously thought to be larger and therefore lacking the atmosphere needed. The other two planets are newly-discovered but are not said to be potentially habitable.

The key discovery was that the planets have masses as low as 1.7 times the Earth’s – the smallest ever spotted around a sun-like star. The planets orbit the star Tau Ceti, which is similar to our sun in size and brightness.

The scientists used the ‘wobble’ method to make the discovery, measuring the effects of gravitational interaction on Tau Ceti. As a planet orbits, it causes its parent star to wobble by a tiny degree. Astronomers can see the signature of this effect in the star’s light.

Lead researcher Dr Fabo Feng, from the University of Hertfordshire, said: ‘Our detection of such weak wobbles is a milestone in the search for Earth analogues and the understanding of the Earth’s habitability through comparison with these.’ The findings are to be published in the Astronomical Journal.