Preliminary evidence that life may exist on a distant planet

Editor-in-Chief: Stelios Vassillodis

NASA’s James Webb Space Telescope (JWST) appears to have discovered initial evidence of signs of life on a distant planet. He may have discovered a molecule called dimethyl sulfide (DMS). On Earth at least, this molecule is produced only by life.

The researchers confirm that its observation on the planet, which is 120 light-years away from Earth, is “not strong” and that more data is needed to confirm its existence. Researchers also detected methane and carbon dioxide (CO2) in the planet’s atmosphere. The discovery of these gases may mean that the planet, called K2-18b, has a water ocean.

Professor Nico Madhusudan, from 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 Earth’s atmosphere is emitted by phytoplankton in marine environments.”

But he described the DMS discovery as preliminary, and said more data was needed to confirm its existence. These results are expected in one year. He continued: “If it is confirmed, it will be a huge deal and I feel a responsibility to confirm it before we make such a big announcement.” This is the first time that astronomers have discovered the possibility of the existence of a DMS system on a planet orbiting a distant star. But they are treating the findings with caution, noting that a similar claim made in 2020 about the presence of another molecule called phosphine — which can be produced by organisms in Venus’ clouds — was disputed a year later.

However, Dr. Robert Massey, deputy director of the Royal Astronomical Society in London, who was not involved in the research, said he was excited by the results. “We are slowly getting to the point where we will be able to answer this big question of whether or not we are alone in the universe,” he said.

“I’m optimistic that we will find signs of life one day. It may be so, maybe in 10 or even 50 years, we will have evidence that will be very convincing and the best explanation,” he added.

The James Webb Space Telescope can analyze the light that penetrates the atmosphere of the distant planet. This light contains the chemical signature of the molecules of its atmosphere. The details can be deciphered by dividing light into its component frequencies, much like a prism creates a rainbow spectrum. If parts of the resulting spectrum are missing, they may have been absorbed by chemicals in the planet’s atmosphere, allowing researchers to discover its composition. What makes this achievement even more amazing is that the planet is more than 1.1 million billion kilometers away from us, and therefore the amount of light that reaches the space telescope is small.

In addition to DMS, spectroscopy detected sufficient amounts of methane and carbon dioxide, with a good degree of confidence. The levels of carbon dioxide and methane indicate the presence of an ocean of water beneath the hydrogen-rich atmosphere. NASA’s Hubble Space Telescope has detected water vapor before, so the planet, called K2-18b, was one of the first to be explored by the more powerful James Webb, but the possibility of an ocean is a big step forward. .

A planet’s ability to support life depends on its temperature and the presence of carbon and possibly liquid water. James Webb Space Telescope observations seem to indicate that K2-18b meets all of the above. But just because a planet has the potential to support life doesn’t mean it does, which is why the potential existence of a DMS is so attractive.

What makes the planet even more interesting is that it is different from the rocky Earth-like planets that have been discovered orbiting distant stars and are candidates for life. K2-18b is approximately nine times the size of Earth.

Exoplanets, which are planets orbiting other stars — and that are between the sizes of Earth and Neptune — are unlike anything in our solar system. This means that these “sub-Neptunian planets” are not well understood, nor is the nature of their atmospheres, according to Dr. Subhajit Sarkar from Cardiff University, who is part of the analysis team.

“Although this type of planet does not exist in our solar system, ‘para-Neptunian planets’ are the most common type of planet known so far in the galaxy,” he said.

“We obtained the most detailed spectrum of the habitable zone to date, and this allowed us to find the molecules present in the atmosphere of K2-18b,” he concluded.

Source: BBC News