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Space

Scientists Believe 'Oumuamua Was Chunk of Extrasolar Pluto-Like Planet (phys.org) 66

lazarus shares a report from Phys.org: Two Arizona State University astrophysicists, Steven Desch and Alan Jackson of the School of Earth and Space Exploration, set out to explain the odd features of 'Oumuamua and have determined that it is likely a piece of a Pluto-like planet from another solar system. Desch and Jackson hypothesized that the object was made of different ices and calculated how quickly these ices would sublimate (passing from a solid to a gas) as 'Oumuamua passed by the sun. From there, they calculated the rocket effect, the object's mass and shape, and the reflectivity of the ices.

The scientists found one ice in particular -- solid nitrogen -- that provided an exact match to all the object's features simultaneously. And since solid nitrogen ice can be seen on the surface of Pluto, it is possible that a comet-like object could be made of the same material. "We knew we had hit on the right idea when we completed the calculation for what albedo (how reflective the body is) would make the motion of 'Oumuamua match the observations," said Jackson, who is a research scientist and an Exploration Fellow at ASU. "That value came out as being the same as we observe on the surface of Pluto or Triton, bodies covered in nitrogen ice."

They then calculated the rate at which chunks of solid nitrogen ice would have been knocked off the surfaces of Pluto and similar bodies early in our solar system's history. And they calculated the probability that chunks of solid nitrogen ice from other solar systems would reach ours. "It was likely knocked off the surface by an impact about half a billion years ago and thrown out of its parent system," Jackson said. "Being made of frozen nitrogen also explains the unusual shape of 'Oumuamua. As the outer layers of nitrogen ice evaporated, the shape of the body would have become progressively more flattened, just like a bar of soap does as the outer layers get rubbed off through use."

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Scientists Believe 'Oumuamua Was Chunk of Extrasolar Pluto-Like Planet

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  • Trying to understand this claim

    "Being made of frozen nitrogen also explains the unusual shape of 'Oumuamua. As the outer layers of nitrogen ice evaporated, the shape of the body would have become progressively more flattened, just like a bar of soap does as the outer layers get rubbed off through use."

    A bar of soap starts out as a flattened shape and roughly maintains its shape through use. I think they need to come up with a better analogy.

  • I'm guessing that fellow who just released a book about it must be royally pissed at this.
    • by gr8dude ( 832945 ) on Thursday March 18, 2021 @04:45AM (#61171632) Homepage

      A key message of the book written by Avi Loeb, if that's what you refer to, is "we should not dismiss 'Omuamua just like that, instead we ought to invest resources into learning more about it".

      He points out that he doesn't mind being contradicted or proven wrong, as long as the discussions are driven by data. In other words, his motivation is to find the truth, which is not an unreasonable attitude.

      • his motivation is to find the truth

        His is; all these other jokers are merely determined to prove what the object isn't.

        Color me unimpressed.

        • by kvutza ( 893474 )

          Considering that he always* sings this only song, his motivation is decoupled from truth already for a long time.

          * He has started as a scientist, yet he turned to something different. Thus not "always", yet "always since a long time ago".

        • His is; all these other jokers are merely determined to prove what the object isn't.

          That's a very important part of science- disproving things.
          This is because our level of physics is reaching the point where actual absolute proof is literally impossible, so all you can really do is disprove things until you can't, and what's left over are the possibilities.

      • At the same time, only Avi was inclined to consider it unnatural. Which seems like jumping to conclusions, even if he tried to soften it with calls for more science.

        Might as well claim its from God or Bugs Bunny.

        • At the same time, only Avi was inclined to consider it unnatural.

          Umm, no. Many, many people were (and probably still are) utterly convinced that 'Oumuamua was an alien space ship. Avi Loeb may well have been one of the few professional scientists to seriously consider the idea, to work out some likely consequences of that, and then to write up and publish those thoughts non-anonymously, but he was far from the only person making these suggestions.

          Personally, I've always found Loeb's work interesting and in

      • The object was near perihelion when it was noticed and long gone by the time Avi Loeb said "Alienz!" Ain't no way to know any more about it than we already do: a few hundred astrometric observations (mostly on the way out), a few spectra, and some radio static courtesy of Yuri Milner and the zomg alienz crew at Green Bank.

        All else is baseless speculation in the absence of data.

  • Next Time... (Score:4, Interesting)

    by ytene ( 4376651 ) on Thursday March 18, 2021 @04:50AM (#61171650)
    If Oumuamua really was extra-solar [as opposed to the much less likely probability that it was a Kuiper belt object that, through a series of slingshot style interactions in said belt, was ejected "inwards" to the inner system] then it's quite possible that not only will we never see it's like again, but neither will our solar system.

    Just think of the probability of a piece of extra-solar matter dawdling across the cosmos for billions of years at a relative crawl, only to intersect and pass through a solar system [ours] whilst that system harbored a planet with intelligence life.

    On the other hand, if it had happened say 10-15 years into our future, who is to say that we couldn't have thrown together an encounter satellite, rammed it with camera gear, fuel and a set of ion thrusters, popped it on the top of an F9 and sent it off for a close fly-by.

    We know that we have the technology to turn around a rocket launch "pretty darn quick". We know that we have several launch companies more than able to put a decent payload on to an intercept trajectory. The only thing we don't have the ability to do right now would be to build a from-scratch intercept vehicle and get it launched in a likely time window.

    But, 10-15 years from now, who is to say that we won't be launching probes to our outer planets every month or two? If we had a well-known design that we'd got some form of cadence or pipeline for, then what I'm suggesting becomes possible. And companies like SpaceX and showing us just how to set up an operation with that sort of cadence.

    Unfortunately, much as I think we have the ability to prepare for "the next time", I suspect that we've just witnessed a once-in-a-several-billion-year event.

    Oh how I hope to be proven wrong.
    • Re:Next Time... (Score:5, Interesting)

      by Sique ( 173459 ) on Thursday March 18, 2021 @05:18AM (#61171712) Homepage

      If Oumuamua really was extra-solar [as opposed to the much less likely probability that it was a Kuiper belt object that, through a series of slingshot style interactions in said belt, was ejected "inwards" to the inner system] then it's quite possible that not only will we never see it's like again, but neither will our solar system.

      If 'Oumuamua were a Kuiper belt object (KBO), it would have a very specific trajectory through the inner Solar system, as you can calculate how much speed it would get by dropping from the Kuiper belt to a near-Earth-orbit. But 'Oumuamua was too fast for a KBO, as a KBO would not go faster than the Solar escape velocity. Thus you can conclude that 'Oumuamua entered the Solar system with a speed surplus, and it will leave the Solar system again, as it went faster than escape velocity. 'Oumuamua being a KBO thus can be ruled out.

      • You missed the part where he said:

        through a series of slingshot style interactions in said belt

        Though that's.... impossibly unlikely. Still "possible" though.

        The same interaction can cause orbital bodies to be ejected from the solar system in the inner system.

        • Though that's.... impossibly unlikely. Still "possible" though.

          No. Really.

          For fuck sakes play with a gravity sim for at least 3 seconds

          • Don't need to play with a gravity sim. I understand the rules gravity follows.
            The vector for the object contains 2 components, as we can model it as a point object (devoid of its own significant gravity): direction and velocity.
            There are many processes that can increase velocity, including but not limited to: gravitational slingshots, outgassing.
            This is how we can get probes to the outer solar system with rockets that can't provide nearly the delta-v for that payload.

            Guessing where the object came from
          • Re:Next Time... (Score:5, Insightful)

            by ytene ( 4376651 ) on Thursday March 18, 2021 @04:08PM (#61173514)
            A couple of quick observations, Rockoon (after: thank you for responding)...

            Some time ago, I read an a piece of research that offered a theory about the possible presence of a fairly large planet [IIRC the paper suggested larger than Earth] that may have been present in the early solar system. The paper discussed a possible historic collision that resulted in the destruction of the planet that gave rise to the asteroid belt before, through the interaction that brought the belt into being, was ejected from the solar system.

            Not being an astrophysicist and not having the means to readily sit down and compute what may have been needed to bring Oumuamua in to the inner system, it seemed like a polite and ‘open-ended way’ to ask my question.

            I thought that Sique’s answer, above, was particularly helpful in expanding my understanding and strongly suggesting the extra-solar nature of this object. Obviously that was just a summary, so I’d need to dig deeper, but I felt the explanation looked sound.

            I’m also very conscious of the fact that the readership age for slashdot extends from perhaps even pre-teens [my godson started reading it eagerly from the age of about 12] through to people in their 80s and 90s with an interest in science and technology. Given this huge diversity of readership it seemed sensible to ask an open question, especially when I had no real clue as to the answer.

            In passing, whilst I value your reply I’d respectfully point out that I don’t have ready access to a ‘gravity sim’ - I presume from the way you phrase your statement that such a piece of software would be freely available for download, but, honestly, I’m not sure that I would have much luck setting it up to simulate the model you suggest. So I’d respectfully ask that you at least consider offer a reply that is a bit more constructive. The mere fact that you took the time to write one suggests to me that you’d like us to understand and accept your point of view, but unfortunately you didn’t really provide enough information to help us get there.

            Finally, whilst I’ve witnessed the frustration of aggressive exchanges on slashdot and whilst I understand that can lead to short tempers, I’d just respectfully ask you to reconsider your use of profanity in future. I’m here to learn; when I ask questions I try to be polite and respectful [sometimes I’m more successful than others] and I’m trying really hard to be polite and not pick arguments with people. I can understand if you’re exasperated by our ignorance, especially if this is a field where you have expertise, but please: think of the wider audience. Chances are that if we all met we’d get along famously: the fact that 80+% of communication is non-verbal [i.e. is posture-related] means it is often difficult to build rapport through nothing more than brief exchanges of the written word.

            But most of us are here to learn. I hope this doesn’t come across as me trying to lecture you ; I’m genuinely grateful for the responses people gave to my post and I hope the exchange gives value to those who read it. I hope you enjoy the time you spend contributing and I hope that you can be understanding of those of us that lack your experience. Thank you.
        • You missed the part where he said:

          through a series of slingshot style interactions in said belt

          Though that's.... impossibly unlikely. Still "possible" though. The same interaction can cause orbital bodies to be ejected from the solar system in the inner system.

          Have you seen a publication that demonstrates this is indeed a possibility? If so, please provide a link. If not, you should write up your analysis and publish (or present your analysis here).

          If you are basing your belief that this really is a possibility simply based on the claim in your last sentence, then you are purely guessing without considering the differences between the inner solar system and the Kuiper belt. Saying that this analogy suggests to you it is possible does not show dynamically it reall

          • Have you seen a publication that demonstrates this is indeed a possibility? If so, please provide a link. If not, you should write up your analysis and publish (or present your analysis here).

            I mean, it's fucking obvious...
            I'm quite certain that if I pick the first publication analyzing the orbit of the body, it will say something akin to "We analyzed that no single solar system interaction could have caused this, but we can't exclude a multiple-interaction scenario via N-body analysis due to the lack of data and the infinite possibilities"

            Do you really want me to do that?

            you are basing your belief that this really is a possibility simply based on the claim in your last sentence, then you are purely guessing without considering the differences between the inner solar system and the Kuiper belt.

            No, I'm basing it on high school newtonian physics.
            A 2-vector is not enough to preclude solar origin. That's up there wit

          • by ytene ( 4376651 )
            I am not sure if I am going to be able to answer your question convincingly, but I was specifically thinking of the https://en.wikipedia.org/wiki/... [slashdot.org]>Oberth Effect, which describes the way in which bodies in space can employ a “gravity slingshot technique” to be able to accelerate.

            Sique had posted that this wasn’t possible, that the velocity with which we’ve observed Oumuamua move through our inner solar system was simply too great for this to be a valid hypothesis.

            I haven
    • Re:Next Time... (Score:4, Insightful)

      by JoshuaZ ( 1134087 ) on Thursday March 18, 2021 @08:31AM (#61172018) Homepage

      it's quite possible that not only will we never see it's like again, but neither will our solar system.

      We've only been able to observe objects like this for a very short period of time. It is pretty unlikely that this is the single extra-solar object that comes by and that it occurred just as we're starting to be able to observe this sort of thing. More likely that such objects happen from time to time and we happened to see one.

    • it's quite possible that not only will we never see it's like again, but neither will our solar system.

      Sure, but it's also quite possible that these things are entirely common.
      After all, there are a fucking lot of objects out there capable of shedding Oumuamuas.

      • there are a fucking lot of objects out there capable of shedding Oumuamuas.

        To a close approximation, a whole galaxy full of them.

        While trying to think of a "fucking galaxyful" like comment, it occurs on me - why did the ancient Greeks liken the Milky Way to "spilt milk", instead of to a cum stain? After all, that's what it looks more like to me. I'm going to propose renaming the Milky Way ... how does the "Ejaculata Galaxy" sound? Like something from a bad 1970s porn movie? The Ejaculata Galaxy on the blac

    • by invid ( 163714 )
      We need to actively keep an eye out for extra-solar objects. Right now we have a count of 1 in the last x number of years that we have had the ability to detected extra-solar objects. If we detect one next year, people will start thinking that the galaxy is chock full of interstellar debris. If after that we don't see any more in another 100 years, then we'd need to revise our thoughts. If the galaxy is chock full of these things, it might curb any desire to fly through interstellar space at relativistic sp
    • by cusco ( 717999 )

      There has already been a second one located, found by Gennady Borisov, an amateur comet hunter in the Crimea, in 2019.

      https://www.nature.com/article... [nature.com]

      I'm seriously surprised that no one else so far in this thread has pointed it out.

    • by jd ( 1658 )

      Apparently models* suggest there are four extrasolar encouters per year, so the odds of encountering something similar isn't too horrible. Nonetheless, it is bothersome that none of the space agencies were in a position to either launch a probe or activate any dormant probe already in space to go and investigate.

      *Given the crowd on Slashdot these days, I should specify these are scientific models involving equations and not any other sort.

  • It should be "TWO scientists believe ...".

    Realistically, they've a hypothesis, one of many. Another is "Thousands of uncritical minds think it's the third stage of an alien rocket". Apply scientific method: make predictions and see if they agree with experiments. Ah, bit of a problem there. The hypotheses are neither provable nor refutable.

    • Thanks to the power of reading TFA (not even, just reading the /. blurb), you would have noticed this:

      Two Arizona State University astrophysicists, Steven Desch and Alan Jackson of the School of Earth and Space Exploration

      Of course it was a bit more complicated than "two scientists", but still...

      • It's still a sensationalist headline.

        Yeah, scientists (plural) believe this. When your headline is "scientists believe..." you're trying to suggest, without actually lying, that it is scientific consensus rather than the maundering of a couple of guys (even if the two guys are scientists).

  • by bill_mcgonigle ( 4333 ) * on Thursday March 18, 2021 @07:24AM (#61171920) Homepage Journal

    Previous studies have shown that the object's orbit is galactic in nature, as is our solar system's, so it 'passed through' the Sol system, but relatively it was rather stationary and our system did most of the moving.

    It wasn't really in orbit of our sun which is why it appeared to interact with it weakly and initial observations were so perplexing - wrong reference frame.

    The sublimation theories require a forcing function increase as it approached our sun which was not observed.

    All we really know is that it's flat, very reflective, and in a galactic orbit that minimizes its apparent motion relative to our local area of space.

    Any thoughts about it being an intentionally-placed navigational buoy are entirely speculative.

    • Previous studies have shown that the object's orbit is galactic in nature, as is our solar system's, so it 'passed through' the Sol system, but relatively it was rather stationary and our system did most of the moving.

      This statement confuses me.
      Any object with a relative velocity greater than the solar system's escape velocity is in a galactic orbit. This does not however mean it started that way.
      Any object ejected from a solar system is now in a galactic orbit.

      I.e., with the proper (impossibly unlikely) gravitational interactions, it could have originated from our solar system. Note, I am not arguing that this is the case.
      But still, I can't see any way you could look at an object's traversal of the solar system and

  • by Framboise ( 521772 ) on Thursday March 18, 2021 @08:21AM (#61171994)

    Stars and their planets move with a typical velocity 30-50 km/s with respect to the local purely circular orbit around the Galactic center, while before coming inside the solar system Oumuamua was only a few km/s from circular orbit. The proposed explanation seems therefore unlikely. Better source of material with a compatible orbits are dense molecular clouds which do move near circular orbit with a couple of km/s difference.

  • It's a brilliant thing to write an academic paper on.

    Literally there is no way in human conception that anyone can test the conclusions, or ever will be able to.

    Come up with something that's just reasonably plausible to the numbers and voila! "publish or perish" staved off for another cycle.

    • Thanks for informing us that no one should ever try to understand any observed unique event and that it is a waste of time to try.

    • by jd ( 1658 )

      There are models that work and models that don't.

      If you have a planetary fragment, you have to be able to generate a fragment of that shape from a planet. We know a cross-section of that shape, so have to guess the rest, but you still have to be able to produce it. A fragment the shape of Rupert Bear is most unlikely to occur no matter how two planets collide, so we can rule that out. Simulations are more than good enough to reduce the possibilities.

      But you've also got the motion to consider. We know the di

    • by Tablizer ( 95088 )

      By the same logic, no scientific papers should be written on the big bang because it's not reproducible.

  • but it's not aliens.

    • While the probability of it being 'aliens' is extremely low ("I will win many lotteries before this happens" odds), the probabilities of these other explanations are low, too (even though they may be one in a thousand). My point is that 'aliens' are more storied, romantic, and self-serving emotionally. They make better lore. If it were not for such talk of aliens, Area 51 would just be a number, Roswell would be only famous by Demi Moore, and UFO would be unidentifiable. The X-Files needed these urban l
  • Scientists believe = SOME scientists believe = A FEW scientists believe. Well, ok, TWO scientists believe.

  • https://www.thesun.co.uk/tech/... [thesun.co.uk]
    got a lot more elon to it, but the "part of a spaceship" one even more ... the only way aliens would ever get close enough to the garbage can of the galaxy for fear of infection by funny ideas and notions on "how to rule the planet" , thats as space debris
    it might just be the container that dropped the primal corona smudge and whats left of it ... saving the planet from the vermin before its too late - its a bit of an oddity and a rarity after all but you dont want your

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