Dr Nikku Madhusudhan: Genius of IIT, MIT! Created history in the world of space
#News Bureau April 18,2025
Indian-origin scientist Dr. Nikku Madhusudhan, a professor at the University of Cambridge, has made a major breakthrough in the quest to find life beyond Earth. Leading a team of researchers, he has discovered a planet located 124 light-years away that shows promising signs. Excitement is building. Learn more:
Nikku Madhusudan, a former student of BHU-IIT and currently a professor of exoplanetary science at Cambridge, has made a surprising announcement while addressing a press conference in Cambridge.
He first published his research paper in the Astrophysics Journal Letters.
He said that his recent observations from the James Webb Telescope have led to the most effective result in all the efforts made so far to search for life outside the Earth. This observation is related to the planet ‘K2-18b’ of a red star located 124 light years away from Earth. Certainly, this planet is very far from Earth and it will take a long time to draw any firm conclusion about it.
But Nikku Madhusudan claims to have found signs of gases of biological origin, dimethyl sulphide (DMS) and dimethyl disulphide (DMDS) in the atmosphere of this planet. If this observation is confirmed by any other team, then this field of knowledge will turn green. Remember, a little discussion on this planet as a possible candidate for life other than Earth was done in an article published in March.
Dr Madhusuden further added that we will come to the complexities related to this observation later. First, let us discuss a little about this planet and its star. The star K2-18 discovered by the Kepler telescope. The planet is smaller than our Sun. Its thickness is 45 percent of that of the Sun and its age is about three and a quarter billion years. Remember, the age of our Sun has been estimated to be around five billion years. The surface temperature of K2-18 is also a little more than half that of the Sun.
The second planet from the inside revolving around this star, K2-18b, is much larger than the Earth. Its radius is two and a half to three times that of the Earth. According to this, its weight should have been 20-25 times that of the Earth, provided its structure was similar to that of the Earth. But in weight it is only eight and a half to ten times that of the Earth. One thing is clear from this that its density is much less than that of the Earth. This can be due to less iron there and also due to more liquid-gas in the planet.
One good thing about this planet is that it falls in the Goldilocks zone of its star. That is, water can be present there in liquid state. The average temperature of the planet has been estimated to be between 23 degrees Celsius to 27 degrees Celsius. This is a surprising thing in itself because its orbit around its star is less than half as small as that of Mercury in our solar system. Understand that if this planet was revolving around the Sun in its current orbit, then rivers of iron and other metals would flow on its surface and perhaps all this would have rained there in the rain. But its star is not that hot, so this is a big blessing for the hope of life.
According to whatever has been known so far about the atmosphere of this planet, discovered in 2015, its air is rich in hydrogen. In the observation taken in 2023, some carbon dioxide and methane were also recorded in addition to water vapor, but in the recent observation, the amount of steam has come down from the last time. One reason for this could be the lack of accuracy of the observation, the other could be that in some special conditions the steam may freeze and go to the surface, and then return to the environment under changed conditions. This time the recording of DMS and DMDS here is indeed surprising, but the presence of these gases in the spectrum cannot be called very subtle either.
Nikku Madhusudan says that these gases emitted by phytoplankton, the most common vegetation of the sea and considered the basis of the marine food chain, have been observed to be present on K2-18B at least a thousand times the proportion in which they are found in the Earth’s atmosphere. So, does this world revolving around a distant star have oceans full of phytoplankton crops, which are the foundation of marine life?
In fact, even if this observation is confirmed, this conclusion cannot be reached directly. Both gases, DMS and DMDS, can also be formed by abiotic means. They are also found from time to time in a completely abiotic way around the hot springs found in the oceans, and a similar story may be going on a large scale on K2-18b as well.
We can say this much only from our experiences on Earth. But the atmosphere of the planet we are discussing here is not made of nitrogen and oxygen like ours, but mainly of hydrogen. We do not know anything about what kind of chemical reactions can be born from the presence of this explosive gas on a very large scale. Before making any guess, we should also talk a little about this wonder with a hydrogen atmosphere.
The weight of a planet plays the biggest role in the formation of its atmosphere. The quantity called escape velocity is derived from the weight of the planet. In the case of Earth, it is 11.2 kilometers per second. Anything from a rocket to a gas should have this much or more velocity to break the gravity of the Earth and escape from its orbit. The average speed of molecules of light gases like hydrogen is fast and after achieving escape velocity in the Earth’s atmosphere, they slowly leak out. But K2-18b is a planet much heavier than Earth. It is not easy even for hydrogen molecules to go out of it, so their presence remains there.
For such heavy planets revolving near their stars, Nikku Madhusudan has introduced a term called ‘Hysion’. A word which is made by combining hydrogen and ocean. Planets revolving near red stars, in whose atmosphere hydrogen can be identified and on whose surface oceans are present.
