The Trappist-1 planetary system includes several planets that are cool enough and recieve little enough UV light for liquid water to exist Nasa/Getty ImagesForty light years away in the constellation Aquarius there is a star orbited by seven Earth-like planets. Now the Hubble telescope has shown that three of them are not only cool enough for liquid water to exist, they also receive sufficiently little UV light that it could persist too. Many planets in the Trappist-1 system orbit their star in the so-called goldilocks zone — the region in which liquid water can exist. However, as well as temperature, UV radiation is critical for determining what happens to water because it can break water vapour permanently into hydrogen and oxygen. Astronomers used the telescope to estimate how much UV light…

Source: The Times August 31, 2017 23:26 UTC