Scientist explains what 'best ever signs of life' spotted by James Webb Space Telescope mean
The discovery of a planet in our galaxy with the 'best ever signs of life' is a significant milestone in our attempts to learn more about the universe around us.
We have spent years peering into the depths of space looking for signs of life, and recently scientists at the University of Cambridge led by Professor Nikku Madhusudhan said they've found one of the best signs yet.
Using the power of the James Webb Space Telescope, they've been looking at a planet known as K2-18b that was first discovered back in 2015.
It's 2.6 times larger than Earth and about 124 light years away, so what we're able to see of it through our telescopes happened a long time ago in a part of the galaxy far, far away....
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The more we've learned of this planet the more encouraging the signs have been, in 2019 water vapour was spotted while in 2023 we found carbon dioxide and methane in the planet's atmosphere.
All of these are positive indicators of a planet that could potentially sustain life, and the most recent discovery made this year found something crucial called dimethyl sulfide (DMS) in K2-18b's atmosphere.
That's a momentous find, but in case you're not a scientist you might not know how huge this is.
Fortunately, LADbible spoke to Dr Michael Steinke of the University of Essex to explain what the discovery of dimethyl sulfide means.
“In layman's terms, it's a gas that appears in our atmosphere," he explained of DMS. "As far as we are aware it's produced by marine biology, by marine life, but there are also some terrestrial plants that produce it.
"There has been lots of research on the production of dimethyl sulfide because it's involved as a climate cooling gas in our atmosphere.
"So wherever there's a lot of this gas, dimethyl sulfide, in the atmosphere, then there are more clouds being formed and cloud shade the plane, they cool the planet so that's good for keeping us at a liveable temperature on this planet."
So if dimethyl sulfide is produced by living things and helps boost conditions favourable towards life then it being found on K2-18b really helps the case that there could be life on that planet.
Dr Steinke explained that life on Earth converts something called long dimethyl sulfoniopropionate (DMSP) into DMS which is then released and ends up in our atmosphere.
He said: "As far as we're aware, the main process of DMS production on the planet Earth is via biological activity.
“I guess that is what the authors of this study that came out today are trying to argue. They’re quite excited about it, I'm quite excited about the find as well."
If production of dimethyl sulfide works the same on K2-18b as it does on Earth then we've got a really big 'tick in the box' that indicates K2-18b could have life on it, and when combined with the previous discoveries of water, CO2 and methane there are already several ticks.
"So they say that this exoplanet actually is a so-called 'hycean world'. It's hydrogen rich, 'HY', ocean covered, 'cean', hycean world, that's how they describe it," Dr Steinke said, explaining how this was even more good news.
“There's water, there's possibly liquid water on their planet, and that obviously forms the basis of life and evolution on our planet, right?"
The expert did add that dimethyl sulfide had been detected on things like comets, indicating that it can be formed without a biological organism.
However, Dr Steinke pointed out that the researchers who have made this discovery raised the possibility that DMS can be created in an environment 'without life', but said that it would need to be 'accumulated on this exoplanet quite high concentrations' which he said would be 'unlikely' as it would require 'so many comet impacts'.
He then added that 'during impact, much of that DMS would be destroyed because of the extreme heat that the impact itself generates'.
So it's possible but unlikely that the dimethyl sulfide detected in the atmosphere of this other planet by the James Webb Space Telescope did not come from something living.
Just in case you're worried about the prospect of life on another planet and what that would mean for humanity, 124 light years away is a chuffing great distance.
The very nature of the speed of light means we are collecting old information, we're seeing this planet as it would have been at the start of our own 20th Century.
Dr Steinke explained that the planet was 'so far away, so tiny, that we cannot see it', and only with powerful instruments such as the James Webb Space Telescope could such a thing be achieved.
With our current technology it would take thousands of years just to get over there and check what was actually happening for ourselves.
But from far away we've managed to spot the presence of something produced by life, it really could be the 'best ever sign of life' we've had.
Topics: Space, James Webb Space Telescope, Aliens, Science
Joe Harker