AS THE RESEARCH BASE GROWS, IT MIGHT NOT BE A CASE OF IF, BUT WHEN WE FIND ET
Somewhere out in the depths of the cosmos, life could be thriving on a strange kind of planet. Around 2.6 times the size of Earth, this alien world would be hot and covered in ocean, with an atmosphere that’s rich with hydrogen. Humans couldn’t survive there, but maybe we could detect the creatures that do. It’s even possible we could make that detection – and confirm that we’re not alone in the Universe – in the next two or three years.
This radical idea comes from researchers at the University of Cambridge, who published a paper in August speculating on the existence of such a world. Researchers have dubbed the category a world like this would belong to as Hycean planets. If the existence of Hycean planets is confirmed, it could turbocharge the search for extraterrestrial life because detecting biosignatures from such worlds is potentially a lot easier than doing the same for Earth-like planets. Plus, a lot of already known exoplanets could fall into this class.
“The fundamental advancement here is that this idea will expand and accelerate the search for life elsewhere,” said study author Dr Nikku Madhusudhan. “In a very practical sense, it literally increases our chances.”
Traditionally, astronomers have scanned the skies for hints of oxygen, methane and other biomarkers produced in large quantities by microorganisms here on Earth.
“On Hycean worlds, we’ll be looking for molecules such as methyl chloride and dimethyl sulphide,” said Madhusudhan. These are also produced by life, but in much smaller quantities – something that’s not a problem when it occurs on Hycean worlds.
“The observability of these [planets’] atmospheres would be so good that even if these molecules are present at one part per million, they’ll still be observable,” he said.
Madhusudhan hopes to take advantage of the soon to be launched James Webb Space Telescope, the largest space telescope ever built. He believes that all it would take is a few hours trained on a Hycean planet for the telescope to pick up biosignatures using transit spectroscopy (a technique in which researchers measure the changes in starlight as it filters through the atmosphere of a planet that’s passing in front of it).
As significant as such a discovery would be, it would also beg further questions. “One fundamental question would be: is life possible in such environments? And how would life originate on this planet? You need to do a lot more follow-up observations to robustly establish whether [what you’re seeing] is indeed a signature of life,” said Madhusudhan.
“I may be risking making a big statement here, but this could be our entry point to extraterrestrial biology. But if you’re quoting me on that, please make it clear I’m saying it with some caution!”