NASA’s Kepler space telescope has detected eight Earth-like planets that lie within the so-called Goldilocks habitable zones of their star systems.
Nasa’s Kepler space telescope detects planets as they move across the faces of their stars. The lead author of the the study, Guillermo Torres, said these were the most Earth-like planets yet found outside our solar system, judging by their size and the amount of light they receive.
The scientists have not been able to assess whether the planets have atmospheres. Two of the newly detected planets – Kepler 438b and 442b – are expected to have mean temperatures of 60 degrees and zero degrees Celsius respectively.
A co-author on the study, David Kipping, said that Kepler 438b and 442b were “as close to Earth analogues as we’re going to find in the Kepler data”.
Kepler 438b is 470 light years away in the constellation Lyra. It completes a 35 day orbit around an orange dwarf star that provides it with 40% more heat than the Earth receives from our Sun. This planet is slightly larger than the Earth. Scientists believe its size and temperature mean that it is likely to be a rocky planet with flowing water – two preconditions for life as we know it.
Kepler 442b lies in the same constellation and is 1,100 light years from Earth, about a third larger, and receives two thirds as much starlight, according to a report published in The Astrophysical Journal.
Scientists are now searching the data for other signs that the planets may be able to support life. The presence of moons, for instance, may be a positive sign, as is the proximity of a giant gas planet. Our Moon helps stabilise the weather on Earth, by stabilising the Earth’s tilt, while our big neighbour Jupiter helps protect the Earth from asteroids and comets.