Two planets, dubbed “super-Earths”, have been discovered in the habitable zone of the nearest Sun-like star Tau Ceti, around 12 lightyears away.
Scientists believe the planets are located in an area that is not too hot or cold to support liquid water – a requirement for life.
Stars which are similar in size to our Sun are considered the best targets for finding habitable Earth-like planets.
Dr Fabo Feng, lead researcher and a research fellow at the University of Hertfordshire, said: “We’re getting tantalisingly close to observing the correct limits required for detecting Earth-like planets.”
The scientists discovered the potentially habitable planets after observing the wobbles in the movement of Tau Ceti, caused by its orbiting planets.
The different sizes in movement were comparable to Earth, between 10 and 30 centimetres a second.
Dr Feng 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 scientists now hope to use direct imaging of the two outer planets to zero in on their surfaces to determine whether they are rocky and habitable.
Dr Mikko Tuomi, also from the University of Hertfordshire, said: “We’re slowly learning to tell the difference between wobbles caused by planets and those caused by stellar active surface.
“This enabled us to verify the existence of the two outer, potentially habitable, planets in the system.”
But the researchers concede that a massive disc of debris around the star could be bombarding them with asteroids and comets and may reduce their habitability.
The news comes as researchers from France’s Université Côte d’Azur, the US’s Southwest Research Institute and the European Space Agency, discovered a cluster of huge ancient asteroids near Mars which reveal the secret origins of the universe.
Meanwhile astronomers from Nasa using a telescope operated by Liverpool John Moores University discovered seven planets which are similar in size to Earth, rocky and probably have oceans.
Six of the planets lie in the habitable zone of a cool dwarf-star known as TRAPPIST-1 which is 39 lightyears from Earth.
And the planets have a surface temperature ranging from zero to 100 degrees celsius – the temperature region which is perfect for supporting life.
Of these six, at least three of the planets have an ocean – and scientists state that anywhere on Earth you find water, you are likely to find life,…