ALIENS might be lurking on a far-off ocean planet in an “astounding” discovery, Britain’s brainiest scientists have told The Sun.
Top alien-hunting astronomers at the University of Cambridge say they’re now 99.7% confident they’ve spotted the best-ever-seen signal of biological activity – and say the planet may be “teeming with life”.
It’s taking place on a distant alien world called K2-18b, which is 120 lightyears away and roughly 2.5x the size of Earth.
Astronomers have picked out a molecule called DMS in the planet’s atmosphere. On Earth, it’s produced by the tiny algae that live in our seas. These ‘phytoplankton’ are microscopic and can’t be seen with the human eye – but in large numbers, show up as coloured patches on water.
And similar alien lifeforms might be churning it out on K2-18b.
Lead scientist Professor Nikku Madhusudhan said “there is no mechanism in the literature that can explain what we are seeing without life”.
He told The Sun: “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.”
SCANNING THE SKY
The astronomers used data from the James Webb Space Telescope, which launched on Christmas Day in 2021.
They’ve spotted fingerprints of two molecules: dihmethyl sulphide (DMS) and/or dimethyl disulphide (DMDS) in the planet’s atmosphere.
These are only produced by life on Earth, usually microbial.
And the results are so convincing that there’s just a “0.3% probability they occurred by chance”.
It’s all taking place on a so-called Hycean world, which planet with a watery ocean and a thick hydrogen atmosphere.
Hycean comes from combining “hydrogen” and “ocean” together.
“If it is indeed a Hycean world, the planet would be covered in oceans,” Professor Madhusudhan told The Sun.
“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.”
WATCH IT GO BY!
We can’t directly see K2-18b because of how close it is to the host star.
So scientists have to use a genius technique to work out what’s going on there.
They watch the star that K2-18b is orbiting, and wait for the planet to pass across its face.
By analysing the star’s light during this “transit”, JWST can pick up the drop in the star’s brightness.
A small fraction of the starlight passes through the planet’s atmosphere.
And the absorption of this starlight in the planet’s atmosphere leaves “imprints” that astronomers can use to work out which gases are present.
Not only did Madhusudhan’s team spot DMS – a biosignature – in the atmosphere, they found it in huge quantities.
Normally DMS and DMDS are found in Earth’s atmosphere at rates of about one part per billions.
But on K2-18b, levels are thousands of times higher – more than 10 parts per million.
“Earlier theoretical work had predicted that high levels of sulfur-based gases like DMS and DMDS are possible on Hycean worlds,” the Cambridge professor explained.
“And now we’ve observed it, in line with what was predicted.
“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.”
He added: “This has been one of the most fundamental questions that we as a species have asked for thousands of years,” Madhusudhan said.
“Everyone would agree that at some point in their lives, they would look at the night sky and ask: are we alone?”
ULTIMATE PROOF
But there’s still more work to be done.
The certainty level is currently three-sigma, which is 99.7%.
Madhusudhan wants to get more analysis time to reach the coveted five-sigma, which means there’s just a 0.00006% probability the results occurred by chance.
“The observation was about eight hours of JWST time,” Madhusudhan told us.
He said they’d need two or three more transits to be certain, which is 16 to 24 hours.
“We have to formally apply for JWST time and there will be a selection process,” said Madhusudhan, speaking to The Sun.
“And if they’re convinced by the case, it’ll be accepted and then the observations will be made.
You’re faced with potentially one of the biggest landmarks in the history of science.
Professor Nikku Madhusudhan
“But these observations are non-trivial to make. They don’t happen very frequently, especially with JWST.
“There are only around four windows of observation every year. So if these observations are approved, this would happen potentially over the next year.”
It’s also possible that the cause of the DMS is non-biological, but Madhusudhan says there’s no known mechanism for this right now.
Source: https://www.the-sun.com/tech/14045828/alien-life-k218b-dms-planet-sign/
