Water Found On Five Alien Planets Nasa

Nasa has reported that "faint signatures of water" have been found in the atmospheres of five planets outside our solar system, marking a further development in the search for planets capable of supporting alien life.

The presence of atmospheric water on exoplanets has been reported before, but Nasa says that this study is the first to " conclusively measures and compare" the light signatures that denote the presence of water.

"We're very confident that we see a water signature for multiple planets," said Avi Mandell, a planetary scientist at Nasa and the lead author of a paper, published on Wednesday in Astrophysical Journal, detailing the new findings.

"This work really opens the door for comparing how much water is present in atmospheres on different kinds of exoplanets, for example hotter versus cooler ones."

The five exoplanets in question - WASP-17b, HD209458b, WASP-12b, WASP-19b and XO-1b - are all 'hot Jupiters', a class of exoplanet that orbits close to their host star and consequently have very high surface temperatures.

All five planets surveyed showed definite signs of water, although the strongest signatures were found in the atmospheres of WASP-17b and HD209458b.

"To actually detect the atmosphere of an exoplanet is extraordinarily difficult. But we were able to pull out a very clear signal, and it is water," said Drake Denning of the University of Maryland in College Park.