Is there life out of earth too? We don’t have the answer till today, but the search is active since the launching of James Webb Space Telescope in 2021, and several new probabilities have also come up.
A Nasa handout image was recorded by the James Webb telescope and obtained on July 12, 2023, in which there is a visibility of a small star-forming region in the Rho Ophiuchi cloud complex, which is the closest star-forming region to Earth.
Past the Solar System, about 120 light years away from Earth, there is an exoplanet present called as K2-18b which orbits the star K2. And the data collected from its atmosphere, recorded by Webb telescope, has now disclosed the existence of carbon dioxide and methane, which are both strong indications of life present there. But it does not strongly indicate that life is present there, but these two additional entities make K2-18b a sure thing open for research.
And in between these two one of them is an “unconfirmed” thing, which now needs to be further explored and verified: the surrounding of K2-18b also seems to existing of dimethyl sulphide, a chemical very strongly related to life. And within Earth, it is manufactured by algae and other related lifeforms; and no other way of building is studied.
The various other thrilling feature is the chance that K2-18b is a member to a proposed class of celestial bodies known as Hycean worlds. Those within the idea pitch Hycean worlds as suitable options for investigation into the possibility of alien life.
The thought of Hycean worlds was been proposed lately, in 2021, and it was a theoretical progress,” astrophysicist Nikku Madhusudan of Cambridge University told in an email reply. Madhusudan had guided the group that first gave the idea (The Astrophysics Journal, 2021) and is also the head writer of the recent study on K2-18b. The new paper has been welcomed for printing in The Astrophysical Journal Letters, he said.
“Hycean worlds are substantially more accessible for atmospheric observations and are therefore more likely to reveal possible signatures of life than rocky planets, if they indeed harbour life,” Madhusudan told.
Ahead of going into what Hycean worlds are like, it assists to know first what it says to find for “signatures of life”.
If there is no sign life on a planet or far off moon, the signal would probably be in the blend of gases in its atmosphere. If the mix is same as of in Earth’s atmosphere, with oxygen, carbon dioxide and methane, these would be an sign of life.
To know the atmospheric composition, scientists try transmission spectroscopy, the science of knowing the spectra of light in the atmosphere, as seen from Earth. Since different substances absorb and emit light at different wavelengths, reading those wavelengths helps knowing about those substances.