Scientists find water on potentially habitable planet, World News & Top Stories

Image Credit ESA  Hubble M. Kornmesser

Astronomers have made a very interesting discovery: For the first time, water vapor has been detected in the atmosphere of an exoplanet that lies in the habitable zone for its star.

This artist's impression shows the planet K2-18b, its host star and an accompanying planet in this system. As the exoplanet resides in the habitable zone, the temperature levels will allow water to exist in liquid state.

The exoplanet K2-18b is what is known as a 'super-Earth, ' meaning it is larger than our planet and, in this case, also has greater surface density. The exoplanet could be a potential super-Earth (a planet with mass lesser than the masses of ten Earths), hinting at the probability of life outside the solar system.

In the dim, red light of an alien sun, scientists have found the first evidence for water in the atmosphere of a rocky planet - offering a tantalizing new target in the search for life in the universe.

NASA's Kepler space telescope first spotted K2-18b in 2015.

While the presence of water vapor in the atmosphere gives us an inkling of a possible life out in K2-18b, the exoplanet is not an ideal planet for us to live in because of its bigger mass. As reported by National Geographic, data was recorded when K2-18b would pass across its star along its orbit which happens periodically after 33 days.

Furthermore, it is argued that K2-18b is more of a super-Neptune than a super-Earth as its characteristics are reminiscent of Neptune than Earth.

Scientists had detected water only in the atmospheres of "gas giants" - huge exoplanets that lack solid surfaces, much like Jupiter and Saturn in our solar system.

"Finding water in a potentially habitable world other than Earth is incredibly exciting", said Angelos Tsiaras, author of the study published in Nature Astronomy. Benneke opined that the research scientists are conducting is aiming toward "being able to study real, true Earth-like planets ..."

The star K2-18 is a red dwarf, smaller, cooler, and much fainter than the Sun.

"K2-18b receives only 5 per cent more radiation than the Earth, leaving it with an equilibrium temperature of 265 K (minus 8 degrees Celsius)", Lothringer wrote in the tweet.

"However, it brings us closer to answering the fundamental question: Is the Earth unique?".

Hubble observations resulted in a distinct water signal, but the UCL researchers weren't certain about the amount of water packed into the atmosphere of K2-18b, or whether liquid water exists at the surface.

The results revealed the molecular signature of water vapour, also indicating the presence of hydrogen and helium in the planet's atmosphere, researchers said. The London data suggest water vapor makes up anywhere between 0.01% and 50% of the atmosphere - "quite a big range", Waldmann acknowledged. Its radiation environment, too, maybe hostile.

Ingo Waldmann, who is also a coauthor of the study and a physics lecturer at UCL, believes that there will be many other super-Earth exoplanets lying in habitable zones - that may contain water - waiting to be discovered in the future.

Though humans are unlikely to ever set foot on the remote world with current technologies, astronomer Jonti Horner of the University of Southern Queensland told ABC the discovery would help researchers understand other Earth-like planets going forward.

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