back to article Quick Q: Er, why is the Moon emitting carbon? And does this mean it wasn't formed from Theia hitting Earth?

The Moon is believed to have formed from the leftovers of a proto-Earth smashing into a Mars-sized Theia nearly 4.5 billion years ago. Now, that has been called into question after a spacecraft detected carbon ions emitted from the natural satellite’s surface. Kaguya, also known as the Selenological and Engineering Explorer …

  1. Zog_but_not_the_first
    Alien

    Perhaps......

    Loonies are pursuing a low-carbon economy?

  2. Blackjack

    Maybe the carbon crash landed there

    After all, the moon is full of holes for a reason.

    1. Notas Badoff

      Re: Maybe the carbon crash landed there

      Might be these guys: Carbonaceous chondrites.

      But surely they've thought that what some people suppose supplied a lot of the carbon to Earth might've supplied a little on the side to good ole Moon?

      Please note "the high-temperature prang should have boiled off all the volatile element" applied to both Earth and Moon - it reset the clock on accumulating new supplies, from... someplace out there...

      1. Wellyboot Silver badge

        Re: Maybe the carbon crash landed there

        >>>applied to both Earth and Moon<<<

        Indeed and there does seem to be so much Carbon around here that we need burn little else.

      2. tfb Silver badge
        Boffin

        Re: Maybe the carbon crash landed there

        I assume that the idea is that the Moon originated from near-surface bits of the pre-Earth combined with whatever hit it, which all both got very hot and spent time as very small chunks of material (either as vapour or as relatively tiny, very hot particles) before coalescing to be the Moon.

        So small fragments have huge surface area, and they're very hot so the carbon boils away.

        Compare that with the big chunk which formed the Earth: this was plausibly cooler (the lost surface layers of the pre-Earth object took most of the collision energy away) and very much larger (it didn't spend time as very hot dust or vapour). So the surface-to-volume is relatively tiny and the carbon boils off more slowly.

        At least some argument like that seems plausible, but note I know nothing about this (I should read about it): I'm just trying to work out how it might have worked, on the assumption that the people who do study this have thought about it.

    2. Michael H.F. Wilkinson Silver badge
      Coat

      Re: Maybe the carbon crash landed there

      Maybe the B-ark had a sister ship that crashed on the moon.

      I'll get me coat.

  3. Paul Crawford Silver badge

    Tsk! It is from burned cheese for making toasties too hot!

    1. Anonymous Coward
      Anonymous Coward

      An attempt at humour, I suppose?

      1. KittenHuffer Silver badge

        Certainly cheesy enough!

        1. Symon Silver badge
          Coat

          It was whey over the AC's head.

          1. jake Silver badge

            Seems it was a non-starter. No culture at all.

            1. JassMan Silver badge

              And in a rarebit of non-science, pundits have decided that Wales is actually a piece of moon which fell back to earth. You need to tread Caerphilly amongst cheesy puns on this site.

              Hard cheddar if AC has no sense of pun. Probably no sense of irony either.

              1. MyffyW Silver badge

                In 1945 we sent two brand new jet aircraft to the Moon to check on the cheese rumour. All we got back was Double Gloucester (Meteors).

              2. KittenHuffer Silver badge

                That's like goldy! Or silvery! But is made of iron!

          2. TeeCee Gold badge
            Coat

            Odd. Anyone curd have got that one.

          3. Anonymous Coward
            Anonymous Coward

            >It was whey over the AC's head.

            A bit of Kurdish humour?

      2. John Brown (no body) Silver badge

        "An attempt at humour, I suppose?"

        Clearly a rare bit in your case. Are you Welsh?

    2. Grinning Bandicoot

      O' Life is bitter

      To the down vote - read the title. Yes this is first of what I hope is a lot of fun spots to make the day easier.

      My theory: it is the volatiles cooking off from the NASA vehicles abandoned on the surface.

  4. Anonymous Coward
    Anonymous Coward

    Nasty Conservative governments fault

    “Japan, analyzed data from that trip, and found the Moon emits carbon”

    “ Carbon is brought to the Moon by the solar wind and tiny bits of floating space debris”

    What’s Greta going to do about carbon emissions from the moon And space?

    How dare the moon and space ruin my kids futures etc etc........

    1. jake Silver badge

      Re: Nasty Conservative governments fault

      "What’s Greta going to do about carbon emissions from the moon And space?"

      That would depend on if her parents ever hear about it, and if they do they decide they have time to coach her into becoming outraged before world science news moves on to something else.

  5. Potemkine!

    Saying that the "Theia hypothesis" is invalidated because of this discovery seems a little bit far-fetched to me. As said also in the article there may be many reasons why carbon would have been brought back to the Moon after its formation.

    1. Pascal Monett Silver badge

      Yeah, mainly all the craters that pockmark its surface.

    2. JCitizen Bronze badge
      WTF?

      Especially..

      since something has to explain why Venus and Mars lost their molten cores at approximately the same time, or there abouts, and Earth didn't? The collision theory is the only one the makes sense at all. And no, I don't believe that water can act as a billion year space blanket to keep the core molten. In fact, if anything it should have accelerated the cool down.

  6. Anonymous Coward
    Anonymous Coward

    And this is why it's always a bad idea...

    to list a hypothesis as "established scientific fact". I've read a couple books recently that talk about how the moon was formed, presenting it as unassailable fact. Which may now be shown as incorrect. If you can't prove it, it's a theory. It may be a good, sound theory that perfectly fits the observations, but call it a theory!

    1. Wellyboot Silver badge

      Re: And this is why it's always a bad idea...

      I blame the general lack of understanding of scientific terms.

      As the A/C points out, any idea about how a possible event caused something to come in being is a hypothesis until enough verified evidence emerges to support it, then it can be elevated to being a theory, it can really only become a scientific fact when independent observers have repeated the event through to the expected outcome.

      The moon existing is a fact (we can see it & go there)

      Gravity is a theory : vast amount of verified evidence fitting the maths, but no observed graviton particle, it is plausible that another better theory will emerge (my money though is firmly on finding the graviton)

      Theia impact is a hypothesis : the only evidence is the similarity between Lunar & Earth surfaces having near identical elemental composition suggesting a common source & a mathematical model that fits this and relevant other theories.

      Conversely it only takes a small amount of verified evidence to burn and replace a theory. Earth surrounded by a shell with the gods visible as moving lights > Earth centric system > Heliocentric system > static infinite universe > expanding universe > accelerating expanding universe (next episode coming whenever!)

      1. Anonymous Coward
        Anonymous Coward

        Re: And this is why it's always a bad idea...

        (Original AC here)

        It's not simply a misunderstanding of the terms. Many things are presented as Fact with a capital F, and anyone who disagrees must be an ignorant moron. In SOME cases they're right - if you claim there's no such thing as gravity, you'd better have a VERY good explanation - but often the "fact" is a hypothesis which fits the available information, but cannot be tested by experiment or direct observation.

        Anything about what happened millions of years ago would be a good example - it's quite fair, in fact expected, to come up with theories/hypotheses that match the available data. But it's a theory or hypothesis, with no way to test it. At some later point, the "fact" often turns out to be wrong, like the list of changes in "fact" that Wellyboot closed with.

        1. John Brown (no body) Silver badge
          Thumb Up

          Re: And this is why it's always a bad idea...

          "but often the "fact" is a hypothesis which fits the available information, but cannot be tested by experiment or direct observation."

          And to turn the above hypothesis into a theory and then into a fact, just watch many of the Ancient Aliens/Curse of Oak Island or similar History Channel documentaries to see how this process can be achieved in a single sentence. It's clearly repeatable as they manage to do it not just in every episode, but multiple times per episode.

          1. jake Silver badge

            Re: And this is why it's always a bad idea...

            One wonders how the so-called "history" channel gets away with its obviously incorrect name. Same for the so-called "science" channel. And don't get me started on "The Learning Channel" ...

            1. Claverhouse Silver badge

              Re: And this is why it's always a bad idea...

              To be fair, since these things are subjective, it is entirely possible that for a certain tranche of people such things are History and are Learning.

              We must avoid being supercilious or condescending to people who think differently, and have their own facts.

              All God's Chillun and all that...

          2. Anonymous Coward
            Anonymous Coward

            Re: And this is why it's always a bad idea...

            "And to turn the above hypothesis into a theory and then into a fact, just watch many of the Ancient Aliens/Curse of Oak Island or similar History Channel documentaries to see how this process can be achieved in a single sentence"

            Just need to watch, read or listen to a Labour / Corbynisyter / Mobmentum fanatic or general anti anything BBC.

            Case in point is the recent Panorama, Monday 27 April: Has The Government Failed the NHS?.

            What the BBC didn't tell the viewers was that the people they interviewed where Labour activists with a history of being anti conservative and an axe to grind.

            https://order-order.com/2020/04/28/panoramas-ppe-investigation-party-political-broadcast/

            Also the BBC initially denied that they consulted with an anti tory union rep to source people for interview and then admitted they did.

            Another one is the BBC claiming NHS procurement contacted them asking for Burberry's number to ask them to make PPE. The BBC plastered that story everywhere in a tone that made the government and Burberry sound bad. The truth was very far from reality & the BBC had to run a retraction.

            https://www.bbc.co.uk/news/business-52333540

            They turned a controversial non story into a fact, and do it lots.

            I used to trust the BBC as a reliable unbiased source, now i don't.

            The guardian is also a rampant source of nonsense, especially that Carol Codwaller.

            https://inews.co.uk/opinion/columnists/isabel-oakeshott-carole-cadwalladr-brexit-truth-opinion-ian-burrell-634627

            Lastly, one of the Blair era quangos expanded and stuffed with Labour sympathisers, the Electoral Commission, after fuelling anti-brexit headlines that Brexit campaigns had cheated, over spent, used foreign funds etc etc, after dragging individuals through proceedings and referring them to the police, 4 years after Brexit the Met Police have now confirmed that no further action will be taken against Vote Leave and BeLeave following investigations into allegations of false declarations of campaign spending.

            https://www.northwichguardian.co.uk/news/national/18436508.police-drop-investigation-pro-brexit-campaigners/

            you won't see prominent mention of that in theguardian or bbc but the negative (for the accused) news and rumors where leading headlines and breaking news.

            The official Electoral Commission statement says

            The National Crime Agency, after its own investigation, has (i) concluded that there is no evidence that any criminal offences have been committed under PPERA or company law by any of the individuals or organisations referred to it by the Electoral Commission; and (ii) has stated that it has not received any evidence to suggest that Mr Banks and his companies received funding from any third party to fund the loans subject to the investigation, or that Mr Banks acted as an agent on behalf of a third party. The Electoral Commission accepts these conclusions.

            yet used damming language at the time when they fined them prompting the BBC to demand an apology from the accused.

            https://www.bbc.co.uk/news/uk-politics-47766407?intlink_from_url=https://www.bbc.co.uk/news/topics/cpz72d0xmm7t/leave-campaigns-spending-investigations&link_location=live-reporting-story

            The public can see through this attempt at stitch up and i think is why they voted conservatives this time. The bias needs to stop if Labour or another party want a shot at power.

            1. Uffish

              Re: And this is why it's always a bad idea...

              Feel better now? Better out than in I always say.

            2. JCitizen Bronze badge
              Unhappy

              Re: And this is why it's always a bad idea...

              Now you've done it! You have spoiled my opinion of the BBC,which I previously thought the most truthful and unbiased news agency in the world! Oh woe is me! Is Al Jazeera the only one left? ;-)

    2. HildyJ Silver badge
      Holmes

      Re: And this is why it's always a bad idea...

      Books are usually outdated by the time they reach print. They also tend to simplify terminology for the general public.

      That said, the theory of a direct impact has been questioned due to a number of findings (the difference between the near and far sides, for example). As I understand it as a layman, the current leading theory is that the collision was a glancing blow, still resulting in a breakup of Theia and striping of Earth's crust but allowing volatiles to survive. The debris ring then formed two moons with the smaller one catching up with and eventually impacting the larger one on what we now term the far side, thus explaining the difference between the two sides and giving that big pink blotch on the latest moon map.

      Now having shown why people tend to avoid technical details, we can go back to discussing the impact of Apollo poop on carbon emissions.

    3. tfb Silver badge
      Boffin

      Re: And this is why it's always a bad idea...

      While you are obviously right, and I'm sure the big-impact hypothesis is talked about by the people who study it as a hypothesis or perhaps a theory or model (the difference is not clear-cut I think), there is a converse danger.

      If I write a book or article which, say, explains that we have a very good theory which explains why 5G does not cause cancer, or COVID-19 or whatever, or that we have a very good theory that explains why carbon dioxide in the atmosphere causes surface temperatures to be higher than they otherwise would be and why this is a fairly serious problem, then immediately people will start saying 'but it's just a theory: it could be wrong'. And they argue from that that, well, since it's just a theory and I'm some elite scientist writing a book I'm almost certainly part of some conspiracy of elite liberal sciency people, and my theory is probably just made-up. And bad things happen as a result: potentially quite bad in the 5G case, very likely civilisation-ending in the carbon dioxide case. And there's a non-zero probability that someone will follow-up to this comment because they believe or claim to believe some of the things which come out of that.

      Obviously everything we know about the how the physical world behaves is not a fact but a theory: Newton's laws (of motion and of gravity!) are just a theory, and they are not even a correct theory. But you probably want to present them to people as facts or laws if you want them to, say, wear seatbelts.

      I think it's a complicated question. (But I wouldn't have presented the giant-impact theory as a fact.)

      1. Anonymous Coward
        Anonymous Coward

        Re: And this is why it's always a bad idea...

        The difference is the level of evidence and the possibility of experimentation. It's easy enough to do a 5G and cancer experiment - set up a 5G transmitter directly on top of a lab mouse cage, so it's 100x the power that a human would get exposed to, and show the mice were fine. CO2 in atmosphere is slightly more difficult, but it can (and has) been proven to be a greenhouse gas, that's quite easy, and the measured temperature change from the lab can be fairly easily scaled up to atmospheric levels. Those could be legitimately

        Compare to "this is how the moon was formed" - can you show me a couple examples? Have we seen a collision on this scale, and so can see the effects? It seems like the whole thing is speculation - Earth and Moon are made of the same stuff, so they must have been one piece originally, right? (Big assumption!) And since they're not now one piece, something must have made them split, so it must have been a huge impact by something else...

        I do find it highly ironic that the selected name for the hypothetical crashing planet is "Theia", which literally means "divine" - the Moon was created via "divine" intervention?

        1. tfb Silver badge
          Boffin

          Re: And this is why it's always a bad idea...

          As I said, there's no hard distinction. It's a theory which makes predictions which can be tested, which tests it can pass or fail. That's all you need to be a scientific theory. Black holes are a lot whackier than this idea, and were, not long ago, regarded as a mathematical curiosity in general relativity. And now we have telescopes which are listening to black holes collide.

          And, well, it is a theory which makes predictions which can be tested: in fact this article is about such a test of the theory, one which it seems to be failing.

          Incidentally you said

          And since they're not now one piece, something must have made them split, so it must have been a huge impact by something else...

          If you assume they were once one object, then that is pretty much the only option for splitting them: you need to dump some deeply spectacular amount of energy into the system: you need something like three hours worth of the Sun's entire power output to lift the Moon & put it into orbit. That's not coming from anywhere we can imaging but from some huge impact. So if you assume that they were once the same thing a huge impact is really the only way we can think of that they got to where they are now.

          1. JCitizen Bronze badge
            Go

            Re: And this is why it's always a bad idea...

            I must say as a layman, and not a professional scientist, that it is easier to believe moons were simply separate bodies that formed apart from the host planet, when you are talking about gas giants. Such large planets could easily capture a moon and it could still be a stable orbit. But with Earth sized planets the moons of Mars are the most believable captured into orbit, because they are much smaller and less massive. To see our moon so large and so close to the Earth is a wonder of planetary evolution to someone like me.

      2. CountCadaver Bronze badge

        Re: And this is why it's always a bad idea...

        My concern is the zealoutry around climate change and the shouting down of ANY alternative hypothesis, the ostracising of any other views rather than rational discussion, whipping up mobs committing vandalism etc who hear carbon and think "death and apocalypse", who think if we miss 1.5C that suddenly everything and everyone on the planet drops dead right after,the rains will stop, the oceans will boil, every tree will burst into flames, crops will all fail en masse, that the seas will shoot up 20 metres overnight, that essentially it will be biblically apocalyptic and anyone who questions anything is tantamount to a murderer or a nazi.

        Worse you have a growing clamour for highly experimental and incredibly risky climate engineering schemes, when even climatologists admit our knowledge of the way the climate functions is far from perfect and that there are vast gaps in our knowledge and that we are learning new things constantly.

        Yes climate change isn't a good thing (and thats puttting it mildly), my concern though is "the road to hell is paved with good intentions" that we try and "cool" the climate and chuck the planet into an ice age or worse change weather patterns that make matters worse not better.

        I'm also not keen on "per capita" emissions, seems a nice way to justify China and India belching out vast quantities of pollution and then using their massive population numbers to make it seem ok, How would the UK's per capita numbers look if the poorest in society still had 11+ children families (like my great grandparents did?) - i.e. those without a car, that can't afford a holiday, that keep the heating turned right down even in the coldest weather as they can't afford to run it due to various levies imposed, that buy secondhand and clothes etc get handed down sometimes through multiple families. I'd wager our per capita emissions would be a lot closer to India due to the sheer volume of people diluting the "unavoidables" like electricity generation, transport etc

        IF we are going to cut emissions and stabilise our CO2 concentrations, then it has to cut across ALL countries at once, otherwise your into diminishing returns, you'd think britain emitted 40% of world emissions the way some talk, when the figure is closer to 1% and dropping (albeit not helped by greenwashing like biomass and wood burning, both of which never close the carbon circle)

        However I don't see their being an agreement about this, I think we need to plan to mitigate the worst - flood controls, water diversion, dykes and dams, building new settlements on higher ground, planning for the extreme worst case and relocate the most low lying settlements / populations over time.

        Lastly I really hate the way in which people (inc the BBC) greenwash electric cars, TopGear magazine even claimed ALL the rare earths etc are now "sustainably sourced" for electric vehicles, no they aren't, as recently as last year one of the major rare earth metal brokers could not guarantee the integrity of their supply chains, could not be sure that conflict mined materials such as those from Democratic republic of Congo were not being bought. the DRC where children and others are forced to mine rare earth metals at the barrel of a gun, where fragile ecology is being destroyed by militias minng to further fund the conflict and all so people in the west can claim moral superiority as they hop into their Tesla X/Y/3, Nissan Leaf, Renault Zoe, VW E-golf etc etc etc.....and then have the audacity to deflect about how they are "doing their bit for the climate" and "it'll be leftovers from copper mining in the 1920s, no one is illegally mining there, govts wouldn't allow it" - it is happening, its just the UK media are either too lazy or too committed to the "green" vehicle revolution to report on it

      3. Grinning Bandicoot

        Re: And this is why it's always a bad idea...

        COVID 19 theories is not caused by 5G but rather by 2G and think of the growths that had started on one ear at that time and followed later wild arm waving coupled with people walking into things. At the same time mental facilities started a decreasing indicating involvement of the nerves

    4. Anonymous Coward
      Anonymous Coward

      For example "Climate Change"

      So much for "the science is settled", science is NEVER settled - good example stomach ulcers, definetely caused by stress, until someone drank a cocktail of heliobacter pylori and promptly manifested stomach ulcers, also recent discovery that much more heat than expected from the sun hits the earth, that it doesn't cool anywhere near as much as had been stated as "fact"

      Personally carbon induced climate change is still at the "hypothesis" stage, there are too many things we don't know yet about the way the climate works and yet cranks are all set to start "geo-engineering" and potentially causing mass crop failures to attempt to protect one area.

      The way that differing opinions about the causes and potential severity of climate change has been shouted down through intimidation, threats, ridicule and downright bullying is utterly shameful, worse that their main figurehead is an uneducated child fed on a diet of the most extreme takes on the situation and taught to scream "how dare you" - how dare her "parents" deny her an education?, how dare they thumb their nose at the law?

      1. Anonymous Coward
        Anonymous Coward

        Re: For example "Climate Change"

        Hear, hear, AC. Posting AC myself as we're both likely to get flamed for not drinking the Kool-Aid.

        I'm quite concerned about the environment, and want to help out. Should we try to minimize our carbon impact? Sure, since CO2 is definitely a greenhouse gas (experimentally demonstrated). But how much is it having an impact on the temperature of the Earth? Can you show me an Earth with a lower CO2 level? How much of the CO2 is from humans, and how do you know?

        How about the ozone hole? Do CFCs play a part? Probably, as they have been shown to deplete ozone. So not using them is a very good idea. How big a part, though? We've been repeatedly told that it's definitely human-caused, but how do we know? And what's the explanation for the 49% jump in minimum ozone from 2018 to 2019, and the 2001-2003 spike (50% again)?

        Perhaps a better focus would be on recycling - namely, fixing it/actually doing it. Heard a reputable news outlet talking about how only 10% of plastic actually gets recycled; the rest is landfilled. The modern recycling movement was started by the plastics and oil+gas industries, who knew full well at the time that the vast majority would actually be thrown away. It was pure greenwashing.

        https://www.npr.org/2020/03/31/822597631/plastic-wars-three-takeaways-from-the-fight-over-the-future-of-plastics

  7. herman Silver badge

    All the planets and the sun originated from the same cloud of dirt created by the last nova.

  8. Arthur the cat Silver badge
    Flame

    It was the Apollo astronauts

    Each mission had a barbecue to celebrate the landing and they tipped out the remaining charcoal when they'd done.

    [Icon is the nearest possible to a barbie.]

    1. John Brown (no body) Silver badge
      Mushroom

      Re: It was the Apollo astronauts

      You've obviously not met my very impatient neighbour. Correct icon for his barby would be -->

      We do still go round when invited a few times per year but have learned to make sure we are at the back of the queue and get the "second cook" when all the lighter fluid taste has burned away.

      1. jake Silver badge
        Pint

        Re: It was the Apollo astronauts

        Lighter fluid? Honestly, why do people persist in the myth that food tastes better when liberally bathed in the smoke of a burning petroleum product?

        Invest in a chimney starter. A decent one[0] costs about as much as a couple cans of lighter fluid, and it'll work for years running on nothing more than two sheets of newspaper per fire. (If your charcoal is dampish and hard to start, spritz about two tablespoons (two ounces, 30ml) of vegetable oil on the paper prior to crumpling it up. Then invest in a proper storage container so you don't have that problem again.)

        Beer. What else would I be serving when the grill is hot?

        [0] I suggest, and use, the Weber Rapidfire ... under 25 bucks[1]. Mine is three years old, and shows no signs of failing any time soon. It has been used a couple times per week since new.

        [1] If you're even stingier than I am, you can make one pretty much for free out of an old bit of flue pipe or a large tin, a couple nuts and bolts, a short length of broom handle, and some bits of wire coat hanger. It won;t last as long as the Weber, but hey, at least it's free!

        1. swm Silver badge
          Mushroom

          Re: It was the Apollo astronauts

          But you miss the foom.

          1. jake Silver badge

            Re: It was the Apollo astronauts

            People who need fooms in their lives can always get tannerite. There is no need to make their food taste like the exhaust of a Trabi ...

        2. CountCadaver Bronze badge

          Re: It was the Apollo astronauts

          Meh I like the taste of charcoal grilled meat but it takes too long to get going and after having a loan of gas grill, its where I'm going when funds allow, just as its quick and convenient and doesn't start with plumes of smoke (though recently I used my propane torch to get things going quicker, much less smoke on startup)

          1. JCitizen Bronze badge
            Pint

            Re: It was the Apollo astronauts

            I had a pellet cooker that made absolutely the best cook out quisine I'v ever consumed. It had a glow starter for the pellets, but was supposed to be a slow cooker, as that is what made the food so good. I just had to start a little earlier cooking, but a remote temperature gauge allowed me to go inside and prepare other items, so it didn't seem slow at all.

  9. Andytug

    It's the high carbon content of the soup..

    ...made by the soup dragon.

  10. tfb Silver badge
    Boffin

    Boiling off carbon

    Assuming there was a big impact, it obviously either did not boil off the carbon on Earth or a fairly large amount was deposited here later. If the second thing is true then you would expect that whatever deposited it here could plausibly also deposit it on the Moon. So I think this means the first must be what people think is true: it got boiled off the Moon but not the Earth. I suppose the argument for that is that the Moon is made of material from Earth's outer layers mixed with material from whatever hit it, and this stuff all got much hotter than the deep interior of the Earth, where our current carbon comes from? That would make sense.

    I don't understand why all the very obvious bombardment of the Moon after it was formed could not have dumped carbon on it though: maybe there's just too much of it.

    However even then this makes me uncomfortable: I'm not sure I can see a mechanism for planets being formed that doesn't involve them starting off rather hot: wouldn't that boil off carbon anyway?

    Obviously this is all idle speculation: I know nothing about any of this.

    1. ThatOne Silver badge
      Happy

      Re: Boiling off carbon

      > you would expect that whatever deposited it here could plausibly also deposit it on the Moon

      Earth has been covered for some time with carbon-based lifeforms, which would explain the major part of the carbon we find around here in some form or another.

      Nothing similar on the Moon though, and while I guess some complicated isotope counting might allow to differentiate between local biological and stellar carbon on Earth, I think the sheer amount of biological carbon is bound to distort the issue: How do we know how much carbon is normal for a larger body of the inner solar system and how much is not, considering they all went AFAIK through a "hot ball of molten rock" phase, something no asteroid has?

      There is apparently a lot of carbon on Venus, and since Venus is quite unlikely to bear carbon-based lifeforms, it might be considered the carbon standard for a bigger, once-boiled inner solar system body. The Moon has clearly a lot less carbon compared to Venus, which might indeed amount to what a twice-boiled body would have left.

      Yes, that's pub science. So sue me!... :o)

      1. tfb Silver badge
        Boffin

        Re: Boiling off carbon

        Earth has been covered for some time with carbon-based lifeforms, which would explain the major part of the carbon we find around here in some form or another.

        They didn't make any of the carbon: they used carbon which was already here. Sadly no kind of life we know about is capable of nucleosynthesis (although it would be kind of cool if they were).

        1. ThatOne Silver badge
          Facepalm

          Re: Boiling off carbon

          You're right...

  11. nagyeger

    Not micro-meteoriods

    Macro-meteoroids? Late-stage bombardment comets (spot the craters)? Recently demised spacecraft?

    10^4/cm2 /s isn't exactly masses... 44.5e6km2 per moon, so that's 44.5e20 / moon, or 0.0089g/s.

    also known as 2800kg/year. OK, so maybe not the Apollo missions.

    I vaguely remember we get C14 from nitrogen + cosmic rays... anyone know what solar wind / cosmic rays does to rock-stuff?

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