Alien life? NASA analyzes molecule on distant planet – 09/12/2023 – Science

A NASA telescope may have discovered possible evidence of life on a distant planet.

This is because a molecule called dimethyl sulfide (DMS) may have been detected. At least on Earth, this is only produced by living organisms.

The researchers emphasize that this possible detection on the planet 120 light years away is “not robust” and more data is needed to confirm its presence.

The discovery was made by NASA’s James Webb Space Telescope. The researchers also found methane and CO_two in the planet’s atmosphere.

The detection of these gases could mean that the planet, called K2-18 b, has an ocean of water.

Professor Nikku Madhusudhan of the University of Cambridge, who led the research, told BBC News that his entire team was “shocked” when they saw the results.

“On Earth, DMS is produced only by life. Most of it in the Earth’s atmosphere is emitted by phytoplankton in marine environments,” he said.

Precaution

But Professor Madhusudhan described the DMS detection as tentative and said more data would be needed to confirm its presence. These results are expected within a year.

“If confirmed, it would be a huge discovery and I feel a responsibility to get it right if we are making such a big claim.”

It is the first time that astronomers have detected the possibility of DMS on a planet orbiting a distant star. But these results are treated with caution, noting that a claim made in 2020 about the presence of another molecule, called phosphine, that could be produced by living organisms in the clouds of Venus, which was challenged a year later.

Even with this scenario still uncertain, Robert Massey, an independent researcher and deputy director of the Royal Astronomical Society in London, said he was excited about the results.

“We are slowly moving towards the point where we will be able to answer the big question of whether we are alone in the Universe or not,” he said.

“I’m optimistic that one day we will find signs of life. Maybe with this current discovery, maybe in 10 or even 50 years we will have such convincing evidence that it can be better explained.”

The telescope responsible for the possible discovery, the JWST, is capable of analyzing the light that passes through the distant planet’s atmosphere. This light contains the chemical signature of molecules in its atmosphere. Details can be deciphered by dividing light into its constituent frequencies — rather like a prism creating a rainbow spectrum. If parts of the resulting spectrum are missing, it will have been absorbed by chemicals in the planet’s atmosphere, allowing researchers to discover its composition.

The feat is even more remarkable because the planet is more than 1.1 quadrillion kilometers away, which means the amount of light reaching the space telescope is minuscule.

Like DMS, the spectral analysis detected an abundance of methane and carbon dioxide gases with a good degree of confidence.

The proportions of CO_two and methane are consistent with the existence of a water ocean beneath a hydrogen-rich atmosphere. NASA’s Hubble telescope has detected the presence of water vapor before, which is why the planet, called K2-18b, was one of the first to be investigated by the much more powerful JWST, but the possibility of an ocean is a big one. step forward.

Recipe for life

A planet’s ability to support life depends on its temperature, the presence of carbon and probably water. The JWST observations seem to suggest that K2-18 b meets all of these requirements. But just because a planet has the potential to support life doesn’t mean it will, which is why the possible presence of DMS has such an impact.

What makes the planet even more intriguing is that it is not like the rocky, Earth-like planets discovered orbiting distant stars that are candidates for life. K2-18b is almost nine times the size of Earth.

Exoplanets (planets that orbit other stars) with sizes between those of Earth and Neptune are different from anything that exists in our solar system. This means that these “sub-Neptunes” are poorly understood, as is the nature of their atmospheres, according to Cardiff University researcher Subhajit Sarkar, who is another member of the analysis team.

“Although this type of planet does not exist in our solar system, sub-Neptunes (with a mass less than giant Neptune) are the most common type of planet known so far in the galaxy,” he said.

“We obtained the most detailed spectrum of a sub-Neptune habitable zone to date, and this allowed us to discover the molecules that exist in its atmosphere.”

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