K2-18b was discovered in 2015 and is one of hundreds of super-Earths - planets with a mass between Earth and Neptune - found by NASA's Kepler spacecraft.
"The search for habitable planets, it's very exciting, but it's here to always remind us that this (earth) is our only home and it's probably out of the question if we will be able to travel to other planets".
Even without an Earth-like surface, Benneke says K2-18b could have a water cycle, with rain falling through the atmosphere, evaporating in a dense and warm gaseous layer lower down, only to rise up again and recondense into clouds.
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For the first time, researchers have detected water vapor signatures in the atmosphere of a planet beyond our solar system that resides in the "habitable zone", the region around a star in which liquid water could potentially pool on the surface of a rocky planet.
In a tantalizing first, scientists have discovered water at a planet outside our solar system that has temperatures suitable for life.
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Although K2-18 b flaunts some of the most Earth-like features observed in an exoplanet so far - water, habitable temperatures, and a rocky surface - the researchers point out the world is still far from Earth-like.
For a more detailed chemical analysis of K2-18 b and other planets like it, scientists will have to wait a few more years when the likes of the James Webb Space Telescope (JWST) and the ARIEL telescope are launched, so that other molecular species can be detected.
Nitrogen and methane may also be current but with present technology stay undetectable, the analysis stated.
As per the findings, the K2-18b exoplanet has water somewhere around 0.01% to 50% in the atmosphere.
The planet, however, has a gravity eight times as strong as Earth's, which means that an average man on its surface would weigh about half a ton. The Montreal-based team's interpretation of its data suggests the hydrogen atmosphere forms a thick, gaseous envelope around the planet.
Water vapour has been detected on a potentially habitable super-earth known as K2-18b, located about 110 light years away. The team, which posted its results yesterday on arXiv and has submitted them to The Astronomical Journal, also acquired data from NASA's Spitzer and Kepler space telescopes and fed them all into a climate model of K2-18b.
Sadly, exoplanets in orbit around red dwarfs are considered poor candidates for habitability, owing to the propensity of this group of stars to produce tremendously powerful and frequent solar flares.
K2-18b is 111 light-years - about 650 million million miles - from Earth, which is too far to send a space probe. This technique measures the difference in stellar light filtered through the atmosphere of the planet with that of the "normal" star light to ascertain any differences.
The British scientists used the data gathered by NASA's Hubble Space Telescope. "These objects are incredibly enigmatic, the so-called sub-Neptunes ... and we have no idea what they are", said Sara Seager, an MIT exoplanet researcher originally from Toronto, who was not involved in the study. Our biases about habitability, he noted, are now very "Earth-centric", which is reasonable given that Earth is the only habitable planet we know of.
The next generation of space telescopes, including the European Space Agency's ARIEL mission, will be able to observe atmospheres in more detail.