Read More: The Guardian
A huddle of seven worlds, all close in size to Earth, and perhaps warm enough for water and the life it can sustain, has been spotted around a small, faint star in the constellation of Aquarius. The discovery, which has thrilled astronomers, has raised hopes that the hunt for alien life beyond the solar system could start much sooner than previously thought, with the next generation of telescopes that are due to switch on in the next decade. It is the first time that so many Earth-sized planets have been found in orbit around the same star, an unexpected haul that suggests the Milky Way may be teeming with worlds that, in size and firmness underfoot at least, resemble our own rocky home. The planets closely circle a dwarf star named Trappist-1, which at 39 light years away makes the system a prime candidate to search for signs of life. Only marginally larger than Jupiter, the star shines with a feeble light about 2,000 times fainter than our sun. “The star is so small and cold that the seven planets are temperate, which means that they could have some liquid water and maybe life, by extension, on the surface,” said Michaël Gillon, an astrophysicist at the University of Liège in Belgium. Details of the work are reported in Nature. While the planets have Earth-like dimensions, their sizes ranging from 25% smaller to 10% larger, they could not be more different in other features. Most striking is how compact the planet’s orbits are. Mercury, the innermost planet in the solar system, is six times farther from the sun than the outermost seventh planet is from Trappist-1.