back to article Juno fly-by detects lower levels of oxygen on Europa than expected

Jupiter's moon Europa has a lot less free oxygen than previously thought, narrowing the odds that life may have evolved in this remote orb. Long thought to be one of the solar systems best bets for hosting extraterrestrial life, Europa witnessed a fly-by from NASA space probe Juno in 2022, giving scientists the opportunity to …

  1. Jonathon Green




    1. Korev Silver badge


      Didn't we vote for Brexit to get out of Europa?

      1. Anonymous Coward
        Anonymous Coward


        No it was to keep the Eastern Europans out.

  2. alain williams Silver badge

    But when life got going on earth ...

    there was no free oxygen so why is it thought necessary for life on Europa ?

    1. Wellyboot Silver badge

      Re: But when life got going on earth ...

      Early life on Earth did produce O2 as a waste product, so until we actually find ET life and the associated bio-markers to look for we’re just going with the known. Free O2 over Europa can’t prove much beyond the level of O2 above the surface*, this in no way identifies the amount of dissolved O2 in the oceans under the ice in a way that can impact the odds of finding life there to any degree.

      *For Europa that’s a really nasty environment to try and exist in, I wouldn’t call it an atmosphere.

      1. werdsmith Silver badge

        Re: But when life got going on earth ...

        I will read the paper when I get the opportunity, but this article doesn't say which hemisphere the 373km pass encountered given Europa rotates about 3.5 earth days being tidal locked with its orbital period.

        There will most likely be more oxygen produced at the centre of Europa's trailing longitudinal hemisphere , and it would not be a uniform abundance across the surface of the entire sphere.

      2. Doctor Syntax Silver badge

        Re: But when life got going on earth ...

        "Early life on Earth did produce O2 as a waste product"

        O2 is a waste product of photosynthesis but in terms of duration I don't think it counts as particularly early. There's no good reason to expect life on another planetary body to have developed along the same lines as on Earth. There's not even a good reason to expect that something as improbable as life would even have developed on another body in the same planetary system. It's just an artefact of observational bias that makes it appear as inevitable.

        1. I ain't Spartacus Gold badge

          Re: But when life got going on earth ...

          Doctor Syntax,

          There's a large assumption in there. We don't know how improbable life is. We find it almost everywhere on Earth, and it may not be that all of it evolved the same way, or at the same time.

          We've been finding possibilities of life in other places in the solar system, though this could just be wishful thinking. But it's possible that there is life around here, we haven't fully checked yet. And that data will give us an indication whether life is in fact massively improbable, or quite common.

    2. ravenviz Silver badge

      Re: But when life got going on earth ...

      Isn't this more to do with the separation of hydrogen and oxygen in water ice by solar radiation? Lower oxygen means lower water ice, the actual ice being nitrogen or methane instead?

  3. lglethal Silver badge

    I'm just curious why free oxygen on the surface would affect the chances of sea life when the top of the surface is frozen. I understand there's a significant transfer of gases between the atmosphere and the ocean here on Earth, so yes here it would have a big effect. but I would imagine that the Ice sheet would act as a significant insulator preventing such a transfer of gases.

    Or (as is likely) am I missing something?

    1. Gary Stewart

      No, you're not. It very likely that anaerobic life converting sulfides much like the ones inhabiting hydrothermal vents in the ocean was the first life on earth. Unless there was an abundance of oxygen available why would Europa be different?

      1. Version 1.0 Silver badge

        We pretty much know what has happened on the Earth but we don't know what led to it happening, our solar system orbits our milky way galaxy about every 250 million years - we have no history but there seems to be the potential for us to pass through vast collections of other life particles ... that might have led to us seeing life in our ocean once it became liquid. And resulted in us having this conversation today.

        Detailed observing things like this example of potential life (and on Mars too) may help us become even more excellently smart life in the Universe in a few more hundred million years. I have always been fascinated looking at the potential of life everywhere.

        1. Doctor Syntax Silver badge

          "there seems to be the potential for us to pass through vast collections of other life particles"

          Where would these have come from and how would they survive in the interstellar medium?

        2. Anonymous Coward
          Anonymous Coward

          Experiments in physically simulating early earth conditions to see if life precursors develop naturally have shown plausible results.

        3. Crypto Monad Silver badge

          Earth is about 4bn years old. The entire universe is about 13bn years old.

          If there was time for life to evolve elsewhere in the first 9bn years (*and* be carried across the interstellar medium to Earth, without being destroyed in the process), then there was almost as much time for it to develop independently on Earth.

          Occam's razor, etc etc.

  4. Wellyboot Silver badge

    If there was a significant atmosphere to retain the Oxygen then the lack thereof would indicate a low chance of life even on an ice covered world, on Europa almost any gas rising from the ice will be stripped by the prevailing conditions and as this was a fly-by there are a whole host of possible reasons that can’t be ruled out either.

    Once satellites are placed into orbit around the Jovian moons we’ll quickly gain the information needed for accurate detailed analysis.

    1. FrogsAndChips Silver badge

      Do you seriously think the Jovians will let us put satellites in orbit around their moons without reacting to this invasion?

      1. I ain't Spartacus Gold badge

        If they complain, we'll just have to send a gunboat. Can't have Johnny Jovian stopping scientific progress, now can we?

        Get a SpaceX Starship. Big silver fins on the back - massive laser cannon on the front. Nuclear reactor for power, sorted!

  5. ldo

    Is This Just Leftover Oxygen?

    If the net production of oxygen is low, could that be not that the production is low, but that something is absorbing it?

    Something possibly ... alive?

    1. Anonymous Coward
      Anonymous Coward

      Re: Is This Just Leftover Oxygen?

      Maybe, but I'm not holding my breath.

  6. Dagg Silver badge

    It's life, Jim, but not as we know it,

    not as we know it,

    not as we know it.

    It's life, Jim, but not as we know it,

    not as we know it, Captain.

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