Water was found for the first time at the air of an exoplanet using Earth-like temperatures which may support life as we understand it, scientists demonstrated Wednesday.
"We can not assume that it has oceans on the surface but it is a real possibility". The exoplanet is probably having a water-based atmosphere but the exact confirmation of helium or hydrogen is still awaited. It is definitely not a gas giant.
The habitable zone is the region around a star where temperatures are considered sufficiently benign for water to exist in liquid form on the surface of a planet. "Finding water in a potentially habitable world other than Earth is incredibly exciting", said first author Angelos Tsiaras from the University College London (UCL) in the UK.
Over the past three years, scientists have obtained thousand of observations of eight transits where the K2-18b passed between the host star and Earth. However, it brings us closer to answering the fundamental question: "Is the Earth unique?" said Tsiaras.
They discovered that the unmistakable touch of water vapor.
In contrast, the proportion of water vapor in the planet's atmosphere varies between 0.2 percent over the rods and around four percent at the tropics.
Water is a must in the quest for life, in part because it absorbs oxygen.
"We've seen water in the atmosphere, but it's a very thick, very heavy atmosphere".
Water vapour was found in the atmosphere of K2-18b, one of the hundreds of "super-Earths" - worlds ranging in size between Earth and Neptune - documented in a growing new field of astronomy devoted to the exploration of so-called exoplanets elsewhere in the Milky Way galaxy.
"With so many new super-Earths expected to be found over the next couple of decades, it is likely that this is the first discovery of many potentially habitable planets", said Ingo Waldmann, study co-author and lecturer in extrasolar planets at the University College London's Centre for Space Exochemistry Data.
"Given it's so far away we don't really have any other choice but stay on our own Earth, so it's important to make Earth great again rather than looking for an alternative to go to", Tsiaras said. ARIEL, slated for a 2028 launch, will canvas some 1,000 planets, a large enough sampling to look for patterns and identify outliers.
A NASA tally now lists more than 4,000 confirmed exoplanets and another 4,000 potential candidates. "By detecting a large sample of planets expect to reveal secrets about their chemistry, formation, and development".