Setback For Hopes of Life As NASA Says Less Oxygen On Jupiter Moon Than Thought (theguardian.com) 25
An anonymous reader quotes a report from The Guardian: New research suggests there's less oxygen on the icy surface of Jupiter's moon Europa than thought -- and that could affect what if any life might be lurking in Europa's underground ocean. Even with little or no oxygen, microbes might still be bustling around in the ocean believed to exist miles beneath Europa's frozen crust. As for what else, "who knows," said the Nasa scientist Kevin Hand, who was not involved in the study published on Monday in Nature Astronomy. More work is needed to confirm these findings, which are contrary to earlier telescope observations of condensed oxygen in Europa's ice, indicating a higher oxygen concentration, said Hand.
The new study is based on data collected by Nasa's Juno spacecraft during a particularly close flyby of Europa in 2022 -- a distance of just 219 miles (353km). A US-European team calculated that between 13 and 39lbs (6 and 18kg) of oxygen are produced every second at Europa's surface. Previous estimates had a much wider spread, with as much as 2,245 pounds (1,100 kilograms) of oxygen produced per second. So "unless Europa's oxygen production was significantly higher in the past," the new measurements provide "a narrower range to support habitability," the researchers wrote. This oxygen is formed, along with hydrogen, as Jupiter's radiation blasts Europa's global shell of frozen water. It is unknown how much oxygen escapes into the moon's atmosphere, how much remains in the ice and how much might find its way to the subterranean sea. The report notes that NASA plans to launch the Europa Clipper this fall. "The spacecraft will make dozens of close flybys of Europa -- nearly the size of our moon -- while orbiting the giant gas planet."
The new study is based on data collected by Nasa's Juno spacecraft during a particularly close flyby of Europa in 2022 -- a distance of just 219 miles (353km). A US-European team calculated that between 13 and 39lbs (6 and 18kg) of oxygen are produced every second at Europa's surface. Previous estimates had a much wider spread, with as much as 2,245 pounds (1,100 kilograms) of oxygen produced per second. So "unless Europa's oxygen production was significantly higher in the past," the new measurements provide "a narrower range to support habitability," the researchers wrote. This oxygen is formed, along with hydrogen, as Jupiter's radiation blasts Europa's global shell of frozen water. It is unknown how much oxygen escapes into the moon's atmosphere, how much remains in the ice and how much might find its way to the subterranean sea. The report notes that NASA plans to launch the Europa Clipper this fall. "The spacecraft will make dozens of close flybys of Europa -- nearly the size of our moon -- while orbiting the giant gas planet."
ALL THESE WORLDS ARE YOURS! (Score:1)
EXCEPT EUROPA. ATTEMPT NO LANDING THERE. (Or we'll blow your ass out of the sky and wipe you out).
Europa was never my top bet anyway. (Score:1)
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I to
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>Build a rocket with a giant oil rig and we can find out.
Or you could send a nuclear powered lander and let it melt its way down with the excess heat it generates, unreeling a tether as it goes to get a signal back to the surface and up to a relay satellite.
Overall, I think that would have a lot less mass to ship there and a lot fewer moving parts to potentially break.
One lesson (Score:5, Interesting)
If there's one lesson the Solar system seems to be teaching us, it's that while life (as we know it) pops up almost immediately wherever it can, the places where it can do that have fairly narrow parameters on them and are probably very rare indeed.
Chemistry says it's almost certainly got to be carbon-based in liquid water, with a gentle energy gradient stable for very long periods of time. Any approximately Earth-mass wet rock in the Goldilocks zone around a high-metallicity G-class or K-class star in a neighbourhood that isn't too crowded should do.
Venus probably never had a chance to collect significant water on its surface, as that would have left a signature in its atmosphere today of elements related to the processes that removed it, a signature that we don't see.
Mars has water even today, but it probably wasn't warm and wet for very long due to its low mass - perhaps for a half a billion years. That's about twice as long as likely took life to start on Earth, so maybe Mars briefly had some single-celled stuff but almost certainly didn't make it to the multi-cellular stage.
So around here it's Earth. Just us. Looking for neighbours we can reach has us looking at sub-surface oceans of the moons of gas giants, hoping for unusual geologic processes that could produce a fundamentally habitable environment like we know it here. We should certainly look, but I'm not crossing any fingers.
If we ever find life outside of Earth likely the only shot to see the evidence up close is Mars, and that's a long shot. After that, we might see the signature of life in the atmosphere of an exoplanet as it is transiting its parent star. I'd actually bet on that if I were younger - so many stars can be examined, and the idea that we're unique in the galaxy never mind the observable universe seems extremely unlikely to me... but at the rate space-based telescopes are progressing I think that discovery will happen a few decades after I'm gone. And we're never going to get to it; I find that kind of disappointing.
Re:One lesson (Score:4, Interesting)
Europa is an interesting prospect though. If its got water and its hidden pretty far below the surface, it means its not getting blasted with radiation (ice is an *excellent* radiation shield). The only thing really missing is a solar (or jovian) energy source, but if theres any vulcanism on IO it could mean theres a subteranean energy source. Im which case I suspect the odds of life might actually be reasonably plausible.
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Indeed. Remember the extremophiles on Earth? Tube worms, crabs, bacteria, and more all living right next to oceanic vents deep in the ocean? I've heard speculation that life might of started there before migrating up.
And if you're going to have a non-oxygen using lifeform, that's where it'd be.
As for energy source - the jovian radiation could be one itself.
That said, it'll all remain speculation until/if we can get a mission there, whether remote or manned. Even then, the first probes are unlikely to be
Re:One lesson (Score:4, Interesting)
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Chemosythesis is an option in the right conditions. We have it here on Earth even today.
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What are you talking about. As far as we know, life has popped up one single time, ever, in the Solar System - all living things on Earth are, somehow, related.
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The more we learn about the likely starting conditions of life, the more we learn the required components occur naturally around the Solar system.
The more we learn about the start of life on Earth, the earlier the starting date seems to be.
In the end, it's math; we estimate that life pops up rather easily given the correct conditions because we know the correct conditions were here (obviously), and more or less as soon as the Earth cooled enough for it, life appeared. The less likely life is to spontaneou
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There are no closed ecosystems on Earth that have persisted for billions of years.
There are no other environments like Earth in the Solar system.
There is an assumption in the math - that we are not special. We could be an outlier where life normally would have taken far longer to appear except for some chain of unlikely events. But the assumption is reasonable until we know otherwise, and the less likely life is to appear, the longer we would expect it to take. Again, there was apparently no significant
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https://en.wikipedia.org/wiki/... [wikipedia.org]
the closest to a 'closed ecosystem' we have found are lakes under Antarctica. In those 'closed ecosystems' they do have life, though those ecosystems aren't really closed because they were open at one time at the very least. So, show me thes
Sensationalistic 2'ry reporting - O2 not relevant (Score:5, Interesting)
I read the original article.
https://www.nature.com/article... [nature.com]
It is not pay-walled. It is a good read. It was a study by smart clever people analyzing Juno data from a Europa close flyby. In distinction to prior model-based estimates of surface ice radiolysis and thus H2-O2 generation rates and fluxes, they calculate gas generation rates based on directly sampled atmospheric data. By their data and calculations, O2 generation is slower than previously predicted.
Radiolysis (coming from Jupiter) occurs only at Europa's surface. If any oxygen permeates through kilometers of ice to get into the oceans below, flux into the ocean is going to be low and slow at best, and now estimates make it even lower. But, in that regard, analysis requires a gazillion assumptions and estimates, so it is hardly more than a mental exercise - and a good one at that - but no one should be surprised at some time in the future that we find out that year 2024 cogitations on the physics of it all missed by a Jovian mile.
Concerning life, the paper makes just one statement :
"Unless Europa’s oxygen production was significantly higher in the past, the O2 production rates found here of less than the 18kgs1 available to be retained in Europa’s surface ice provide a narrower range to support habitability than previous model-driven estimates."
The problem though is that oxygen is irrelevant and inconsequential to a discussion of life in this context.
The people writing the report seem to be very capable objective scientists. Any subjective or sensationalistic re-interpretation of their work - SETBACK of Hopes for Life - comes from the Guardian report, yet another instance of the terrible "science reporting" for ad dollars that has destroyed real journalism.
Earth's early atmosphere had "no" oxygen - probably a lot like Titan. Earth life arose in the chemical medium of its day about 3 billion years ago. Nature devised a number of ways for organic chemistry to capture energy, and in the earliest days, it is thought to have been heat such as near hydrothermal vents. Photon capture photosynthesis led to oxygen generation and an oxygen atmosphere supporting aerobic life, but that was a late event, and even now there are countless microbial organisms that thrive on non-aerobic chemistry.
So, life on Europa, if there, deep in the dark, is very unlikely to have anything to do with oxygen. The Juno data is not a setback for anything - except perhaps for some people who should spend less time writing foolish popular media stories and read up on real science and try reporting that.
On Earth, most life, whether prokaryote or eukaryote, anaerobe or aerobe, has a certain common core chemistry based on nucleotides and phosphorus to shuttle electrons and handle the redox reactions needed for extrinsic "source" energy to be captured and turned into metabolites, e.g. ADP/ATP, NAD+/NADH. One can presume that one day in the future we will be there to get direct samples, and then we can see if that chemistry is "universal" or if nature is full of surprises that we cannot even guess at.
If the Monolith allows it.
But - one last thought:
"Unless Europa’s oxygen production was significantly higher in the past, the O2 production rates found here of less than the 18kgs1 available to be retained in Europa’s surface ice provide a narrower range to SUPPORT HABITABILITY than previous model-driven estimates."
Perhaps the research authors were not talking about natural evolution of life but rather about a habitable environment if we ever go there and need to harvest free oxygen to sustain our lives and activities (knowing for instance that light levels that far from the sun might not suffice to run an electrolytic oxygen generator at required capacity). In that sense, the authors might have clarified what they were referring to.
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Many /. postings are designed to elicit argument.
It usually works and sells ads.
Great summary, btw - thank you.
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[...] found here of less than the 18kgs1 available [...]
That's 18kg/s for anyone wondering about the units.