Distant system could nurture alien life
UNITED STATES: Extraterrestrial life could be identified within a decade, Nasa said yesterday, as it announced the discovery of seven Earth-sized planets in a solar system about 39 light years away.
The space agency hailed the ‘‘seven sisters’’ as the most exciting discovery made by its Spitzer space telescope in its 14 years of operation.
Thomas Zurbuchen, of Nasa’s science mission directorate, said: ‘‘The discovery gives us a hint that finding a second Earth is not just a matter of if but when.
‘‘Are we alone? We are making a leap forward to answering this question. Just imagine how many worlds are out there that have a shot at becoming a habitable system that we could explore.’’
The newly found planets orbit an ultra-cool dwarf star known as Trappist-1 in the constellation of Aquarius. The six inner planets lie in a zone where surface temperatures range from zero to 100 degrees Celsius. Three are thought capable of having oceans, increasing the likelihood of life.
The planets orbit near their star, meaning they have years ranging from 11⁄ to 13 Earth days. The star has a surface temperature less than half that of our Sun.
A human visitor to one of the planets would see ‘‘a beautiful spectacle’’ lit by salmon-coloured starlight, according to Amaury Triaud, of Cambridge University, part of the team that have published a study of the findings.
He added: ‘‘The light would be 200 times less than full daylight on Earth, like what we see at the end of sunset. We can expect that, within a few years, we will know a lot more about these planets, and we hope, if there is life there, [we will know] within a decade.’’
The study authors said the Trappist-1 system is extremely compact. The planets are much closer to each other than those in our solar system, meaning each would have ‘‘wonderful’’ views of its neighbours. – The Times