James Webb Space Telescope discovers ‘best ever signs of life’ on alien planet with '99.7%’ certainty

Astronomers say they are ’99.7 percent’ certain that they've come across the best-ever sign of alien life.

Scientists at the University of Cambridge think there is a very good chance that aliens may be lurking in a galaxy far, far away...

124 light-years away is ​K2-18b, a distant world orbiting a red dwarf star in the constellation Leo. It was discovered in 2015 by NASA’s Kepler Space Telescope and it's approximately 2.6 times the size of Earth.

In 2019, experts detected water vapour in K2-18b's atmosphere, which marked it as the first habitable-zone exoplanet where was water was found.

This year, however, there was another breakthrough after the James Webb Space Telescope detected gases such as methane, carbon dioxide, and notably, dimethyl sulfide in K2-18b’s atmosphere.

The James Webb Space Telescope has discovered the ‘best ever signs of alien life’ (NASA)

So on Earth, dimethyl sulfide is produced by marine microorganisms like plankton.

The presence of it on K2-18b suggests potential biological activity, as no known non-biological processes can produce it in significant amounts, says lead scientist Professor Nikku Madhusudhan.

He told The Sun that 'there is no mechanism in the literature that can explain what we are seeing without life'.

"It’s a question humanity has been asking for thousands of years. It’s a shock to the system. It takes time to recover from the enormity of it," he said.

Based on the results, the expert insists that there's a '0.3 percent probability they occurred by chance'.

Scientists are increasingly confident given that the discovery was made on a Hycean world, where the planet consists of a watery ocean and a hydrogen atmosphere.

Scientists at the University of Cambridge have called the discovery 'a shock to the system' (Getty Stock Images)

“If it is indeed a Hycean world, the planet would be covered in oceans,” Professor Madhusudhan told the outlet.

“We currently don’t know what the temperature of those oceans would be.

“But we expect it to be slightly warmer than Earth.

“On Earth, extremophiles have been known to survive at very high temperatures, so that is not itself an issue.”

“Earlier theoretical work had predicted that high levels of sulfur-based gases like DMS and DMDS are possible on Hycean worlds,” the Cambridge professor added.

“And now we’ve observed it, in line with what was predicted.

The presence of dimethyl sulfide on K2-18b suggests potential biological activity (Getty Stock Images)

“Given everything we know about this planet, a Hycean world with an ocean that is teeming with life is the scenario that best fits the data we have.”

Madhusudhan went on to add that the question of whether there could be alien life out there is 'one of the most fundamental questions that we as a species have asked for thousands of years'.

“Everyone would agree that at some point in their lives, they would look at the night sky and ask: are we alone?” he continued.

However, others are more skeptical, with Ryan MacDonald from the University of Michigan saying that any claims of 'life beyond Earth' must be thoroughly checked, as he told The New Scientist: "Unfortunately many previous exciting claims for K2-18b haven’t withstood these independent checks."

Although the findings are promising, it's important to note that the detection of dimethyl sulfide, alone, is not definitive proof of extraterrestrial life, as Madhusudhan adds: "We cannot, at this stage, make the claim that, even if we detect DMS and DMDS, that it is due to life. Let me be very clear about that.

"But if you take published studies so far, then there is no mechanism that can explain what we are seeing without life."