Image Credit: ESA/Hubble, M. Kornmesser

Is it another earth in our galaxy? Or something dicy we’re roaming around. On Wednesday, astronomers announced the first detection of water in the atmosphere of an exoplanet named K2-18b. The scientists revealed that the planet is certainly not habitable as it’s a mini-Neptune without any solid surface and likely to have hydrogen/helium-rich atmosphere. The exoplanet is probably having a water-based atmosphere but the exact confirmation of helium or hydrogen is still awaited. The planet exists in our habitable zone of its host star.

The discovery of this exoplanet (K2-18b) is evidence which reveals that our Earth is not the only planet having water at a distance from its star. The report suggests that K2-18b was discovered during the extended second mission of the Kelper space telescope. Kelper used NASA’s trick on how to keep the optics stable by using the solar panels to determine the existence of water on this potentially habitable planet.

This K2-18b is not the only planet our scientists have discovered with the possibility of life but the one seems to possess liquid water which could feed human life. The planet was discovered during the extended mission of the Kelper space telescope.

The detailed study of the planet K2-18b reveals that the planet is large in size and its mass is over eight times that of Earth. While the planet is close enough to its host star that it only takes 33 days to complete its orbit. As the host star is quite smaller which is cooler than sun and closes the planet K2-18b it is expected that the planet to gain a little more light than Earth. But the light is sufficient to maintain a temperature which can allow the existence of liquid water.

Life on this newly found exoplanet could be possible if it’s having actual temperature instead of a fluctuating one. The life over this planet also depends on the greenhouse gases in the atmosphere. The structural study of the planet shows that it is large enough to have its origin with Hyrodgen and Helium, but for the existence of life, the presence of other gases are yet to be confirmed. The planet likely resembles Nepture with no solid surface with fluctuating temperature and pressure.

Some reasons project that life could be possible on K2-18b due to its close distance with its star and large probability of light of its star to pass through the atmosphere. And as the planet completes rotation of its orbit in 33 days hence it would not be typical for us to measure the fluctuations and variety of atmosphere present there in a few years.

This could also be possible that the water vapour got detected only in the habitable zone of the planet while there would be a shortage of habitable atmosphere.

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. And these were the observations from Kelper itself, as well as some data from the Spitzer space telescope.

The surface was then tested for various components to confirm the existence of life on the exoplanet and these components include H2O, CH4, CO, CO2, NH3, HCN, H2S, C2H2, O2, OH, PH3, Na, K, TiO, SiO, H−, VO, HDO, and FeH. And the software also considered the presence of clouds, which will scatter the light in various wavelengths.

The “habitable zone” doesn’t mean “habitable” but results are still favourable in various levels. We have already seen water vapours on some other planets as well but there are nothing bas to expect that we could find life on this new Earth.


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