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Could 'Oumuamua be an icy fractal aggregate ejected from a protoplanetary disk?

509 points by Santosh83 8y ago

gus_massa 8y ago
At least this makes sense. Perhaps calling it a fractal is an unnecessary spin, but if it is linbaity enough to cover the spaceship theory I'm in. More than a fractal, it is better to imagine it as a pile of recently fallen snow is a day with the correct climate (cold?), so the snow accumulates but it doesn't compact too much. So the density is much smaller than the density of ice that has been in a glaciar for years under a lot of pressure. Since the gravity is too low, it will no compact too much. The main difference is that it's not a pile of real snowflakes, ut a pile of dust "snowflakes". Otherwise, the ice in the real snowflakes would have been partially evaporated by the sun and it will be classified as a comet. Anyway, it would be interesting to read more technical details about the plausibility of this. Can the dust pile survive the micrometeorites? Does the color profile match a dust pile object. I really don't like the starship hypothesis paper, but at least it contains a good analysis of many of the (secondary) objections.
- sandworm101 8y ago
  And can that loose pile of dust survive even a slight rotation. If it is long and thin, the dust near the tips should separate.
  - gmueckl 8y ago
    There are mechanisms by which tiny particles may bond over time without becoming more dense. The only prerequisite is that individual atoms or molecules can move on the surface of the particles. This is true for a wide range of conditions, but usually is extremely slow.
  - acqq 8y ago
    The article claims that if it has the snowflake properties it isn’t long and thin and still produces what we saw.
- jerf 8y ago
  "Perhaps calling it a fractal is an unnecessary spin," It is, or at least calling it self-similar is, as well as what the image implies: https://www.youtube.com/watch?v=gB9n2gHsHN4 https://www.youtube.com/watch?v=gB9n2gHsHN4 That's a 3Blue1Brown video explaining why "fractal" and "self-similar" are not the same thing.
  - gowld 8y ago
    That video is about how "self-similar" is not sufficient for fractal. (The rest of the requirement is some notion of fine detail at every scale, which the video focuses on.) It is widely agreed that self-similarity is required for fractal, although often interpreted as quasi/statistical/multiple similarity https://en.wikipedia.org/wiki/Fractal https://en.wikipedia.org/wiki/Fractal Put another way, some things are self-similar but lack detail (for example, a straight line), and some things have detail but not similar detail at all scales (for example, a meterstick with ticks at every millimeter) and some things have infinite detail but no similarity (for example, purely entropic noise that cannot be compressed or expressed as a structure)
    - karmakaze 8y ago
      The core idea of a fractal is something having fractional dimension. It just happens that the ones we know of are self-similar. If we had a formula that generated different shapes ad infinitum, I would also call that a fractal.
    - jerf 8y ago
      It may be "self-similar" in a particular mathematical way, but fractal does not imply "self-similar" in the way people expect.
    - aoeusnth1 8y ago
      I think you meant "not necessary".
- Gibbon1 8y ago
  > Perhaps calling it a fractal is an unnecessary spin It's a GIANT INTERSTELLAR DUST BUNNY!!! slinks away
- gene-h 8y ago
  It makes more sense to call it a fractal rather than a pile. In the paper they reference, it is suggested that particles can form fractal like structures through a diffusion limited aggregation process[0]. One very important result in planetary science is the observation by the astronaut Donald Pettit of granular materials aggregating together in microgravity[1]* . In the experiment[2], it appears that some of the resulting structures resemble those formed in a diffusion limited aggregation process. *It is also worth noting that this experiment was entirely ad-hoc and came about from Don basically just playing around with stuff in microgravity [0]https://arxiv.org/pdf/1402.7132.pdf https://arxiv.org/pdf/1402.7132.pdf [1]https://www.lpi.usra.edu/meetings/lpsc2004/pdf/1119.pdf https://www.lpi.usra.edu/meetings/lpsc2004/pdf/1119.pdf [2]https://www.youtube.com/watch?v=k0YuivnCXhM https://www.youtube.com/watch?v=k0YuivnCXhM
  - borkt 8y ago
    For example, bismuth crystals grow in an interesting way and, like h20 are less dense as a solid than a liquid. At the utterly extreme temperature/pressure environments expereinced in the universe, it isn't hard to believe there are solids out there we can't begin to predict at present. Below are some 3D crystal growths at SEM and macro scales for earth examples https://i.pinimg.com/originals/5d/bf/9c/5dbf9caa3ece888f2dc2f3b24bb0673f.jpg https://i.pinimg.com/originals/5d/bf/9c/5dbf9caa3ece888f2dc2... https://www.doitpoms.ac.uk/miclib/micrograph_record.php?id=617 https://www.doitpoms.ac.uk/miclib/micrograph_record.php?id=6...
- jcoffland 8y ago
  > More than a fractal, it is better to imagine it as a pile of recently fallen snow But snow flakes are fractals.
  - lippel82 8y ago
    But a pile of snow is not.
  - qubex 8y ago
    And snow ‘falls’ in gravity. This aggregated somehow else.maybe by tenuous electrostatic attraction (some ice particles get positively ionized when a photo kicks out an electron, some get negatively ionized when an electron attaches to them, & cetera and eventually they clump together to make a roughly electrical neutral object. The. Hydrogen bonds kick in once it’s electrically neutral (assuming it’s made of water or other polar molecules).
    - philipov 8y ago
      Why does it have to be something else? Couldn't the particles have precipitated gravitationally inside a smallish dust cloud?
- lallysingh 8y ago
  It's Wired. They have to use "fractal" a few times an issue or their articles of incorporation call for a new board.
  - eric_h 8y ago
    It’s Phil Plait on the Syfy blog Bad Astronomer, not Wired. He does occasionally get a bit click-baity in his headlines but the content is pretty solid, particularly on the subject of omuamua
    - lallysingh 8y ago
      Oh wow, you're right. I saw the green-underlined all-caps text and assumed Wired. That and the word fractal.
  - qubex 8y ago
    Funny you mention that. I seem to remember them classifying it as a “meme that died from overexposure” in their regular feature sometime back in 1997 or thereabouts.
excalibur 8y ago
I don't know that this theory is any "weirder" than an alien spacecraft, but it's certainly more plausible.
- roberttod 8y ago
  I can't see how it's anywhere near as weird as an alien spacecraft. Interesting article though.
- arxpoetica 8y ago
  Plausible or less deniable?
coolspot 8y ago
> Assuming a size for 'Oumuamua of 50 – 130 meters, what they get is a very low density: About 0.00005 grams per cc. Do we have example of naturally ocurring space object with such low density? Half-close? Quarter-close?
- downer52 8y ago
  There's a first time for everything, no?
- deleted 8y ago
  [deleted]
- privong 8y ago
  > Do we have example of naturally ocurring space object with such low density? Depends what you mean by "object. Assuming the mass is mostly protons, that corresponds to a density of ~3e19 particles per cc. In comparison, molecular clouds in the galaxy have regions which are have densities as low as 1e2 particles per cc. And the hot X-ray emitting gas in clusters can be less than 1 particle per cc. There are things which span the gap, including disks around stars.
  - jcriddle4 8y ago
    By object he is probably talking about matter in a solid state which would exclude gas or plasma. Also given Oumuamua's rotation rate the pieces of matter that makes up the object probably has to have some bounds with each other or it would fly apart.
- Symmetry 8y ago
  Even an aerogel is .0.2g/cc. That sounds implausible to me but so does the solar sail hypothesis. And really we don't have much information about what an interstellar object would be like.
  - gus_massa 8y ago
    I agree that the proposed density is too low. Anyway, the aerogels are deigned to support their own weight on Earths, wind currents and some moron poking them. The magical aerogel of this object may have lower requirements.
27182818284 8y ago
The idea it is a fractal structure is not weirder than the idea it is possibly an alien probe sent over the course of hundreds of thousands of years to pass by our Goldilocks-zoned planet for observation. Does anyone know more about the initiatives by Yuri Milner with respect to this? I heard something like he is helping fund satellites that could specifically be better at looking at 'Oumuamua than our current means?
- magduf 8y ago
  We can't look at 'Oumuamua any more, with any kind of spacecraft. It's headed out of the solar system. There's absolutely no way we could possibly put together a mission and build a craft and launch it and have it catch up with 'Oumuamua at this point. If we had something ready to launch now, it might be possible to catch up with it, but it would be years before we could have a mission ready to go, and we don't have the propulsion technology necessary to catch up with it after that much time. This should have been a big wake-up call to have pre-made probe craft ready to launch to investigate anything odd that entered the solar system. But expecting humanity to be that fore-sighted is pure folly.
  - LifeLiverTransp 8y ago
    We can foresee our lack of foresight- so its not hopeless.
    - magduf 8y ago
      I'm sure there were some people who could foresee the lack of foresight before the collapse of Rome too. It didn't help them.
  - jandrese 8y ago
    Oumuamua is traveling at 26kps. For comparison the Voyager probes are traveling at around 17kps. Even if we had a probe ready today it's already too far and moving too fast to overtake. Even if we had a probe ready when we first detected the object it would have been difficult to intercept with today's technology. It would have to be something like a Falcon Heavy already in orbit and ready to burn at a moment's notice with a tiny probe at the top for gathering the data.
GlenTheMachine 8y ago
I'm curious about whether an object with a density this low could survive the gravity gradient it experienced during the solar flyby.
- jefb 8y ago
  As am I. The paper dedicates one sentence to that question: "... another aspect that needs to be studied is whether its extremely low density could be maintained while in the parent system, during its long interstellar journey, and when entering the solar system." Without analyzing the structural integrity of such a fluff ball it's tough to give any more or less merit to this concept than the others.
- ars 8y ago
  Unless it's very large why would there by much of a gravity gradient? It never came all that close to the sun, so the gradient on different parts of it wouldn't be that extreme.
  - GlenTheMachine 8y ago
    There wouldn't be a large gradient. But a big ball o' fluff presumably has essentially no internal cohesion; it's sort of like a liquid in that way. So even very small gradient forces could be enough to disperse it.
    - ars 8y ago
      So lets run the numbers: At Perihelion it was 38198320 km from the sun = an acceleration of 0.090962666582226 m/s^2 It's 1km long so on the other end the acceleration is 0.090962661819574 m/s^2 Subtract: .000000004762652 m/s^2 which is such a small amount I'm not sure how to put it into context. Multiply by 1 metric ton = 1/5 weight-force of a single snowflake on earth. Which means each metric ton of material needs to handle just that much force trying to separate it. i.e. it won't be ripped apart in the slightest. Over centuries it might elongate a bit (and it's already elongated).
komali2 8y ago
> It seems far more likely that objects like 'Oumuamua are relatively rare, and that means it likely came from someplace close by (if it came from farther away, the odds are even lower we'd ever see one). Ok, it's on my list of things to do this year to actually learn how statistics work, but my naive reaction to this supposition, which I read is "the fact that we have encountered Oumuamua means that it's likely it didn't come from far away, because if it did, it's less likely we would have encountered it," is: We did encounter it. Just this one, ever. How can we draw any statistical information from that? Either we encountered it, or didn't, how does that have any bearing on the statistical probability of seeing it?
- nerbert 8y ago
  We did encounter it during the short timeframe in which we would be able to detect it. Could be a once every 20 years occurrence, that would make it quite frequent.
- azeirah 8y ago
  I don't know much about statistics, but I can add that the time period matters. If we only started observing space yesterday, and saw it, it would be weird to say "it's rare", but we've been observing space for, I don't know, up to 400 years? (counting since invention of telescope, 1608)
  - nkrisc 8y ago
    I don't think an object like this could have been spotted until relatively recently.
  - polityagent 8y ago
    But how recently have we developed the capability to: - observe this thing at all - accurately measure it's velocity and acceleration - understand that it's velocity and acceleration were unusual?
  - KineticLensman 8y ago
    > but we've been observing space for, I don't know, up to 400 years? (counting since invention of telescope, 1608) We've been observing space 'forever'. Pre-telescope observers had quite accurate star maps (of the naked-eye stars, obviously) and were fully aware of the complex movements of the planets. Their models of the movements were good enough for predictions even if the underlying explanatory causal models were sometimes wrong.
deleted 8y ago
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crispyambulance 8y ago
No one can say for certain what Oumuamua actually is-- other than it is "a surprise". What it really is, IMHO, is a call to action for better instrumentation so that the next time one of these things pays us "a visit", we're in a position to find out more about it.
- gammateam 8y ago
  Solar Defense Force!
- rjf72 8y ago
  And better rocket come 'space ship' preparedness. You can only learn so much about things from millions of miles away regardless of your resolution. It's a very serious problem that our space program has severely regressed. In 1969 we put men on the moon and brought them back home safely. In 2019, we struggle to send a man on a flyby around the moon! It's frustrating because we already have the technology to be able to achieve basic intercepts here, even if they were at high velocity. The only thing in the way is a dilapidated space program.
  - planteen 8y ago
    Manned exploration may have reached a zenith in 1969, but science did not. In 1969, the field of planetary science did not really yet exist. Since then, we have done flybys of every planet, intercepted comets and asteroids, put orbiters around many of them, landed probes on more, and even had robots driving around! A ton of science has happened since 1969.
    - rjf72 8y ago
      I would not disagree, though the Soviet Union had already put a probe within the atmosphere of Venus in 1967. In 1970 they landed a probe on its surface!! They were called the Venera [1] probes. They also returned audio and picture from the surface of Venus. Absolutely remarkable if you're never heard it before. This [2] is the sound of the probe coming down through Venus' atmosphere, its landing, the lens cap (for the camera) popping off, the deploying of the drill, and then the drilling of course. In my opinion that remains arguably the most remarkable achievement in planetary science in our solar system. Although it must be said that that audio came much later than the earlier probes. "Much later" being about 40 years ago. I think the recent discovery/confirmation that our moon has substantial reserves of water ice emphasizes the difficulties with technology outside of manned exploration. There's a lot of information you can obtain from probes and other forms of remote observation, but it tends to be extremely specialized and very limited. This is not something we should be discovering 40 years after landing on it -- water was confirmed in 2009. [1] - https://en.wikipedia.org/wiki/Venera https://en.wikipedia.org/wiki/Venera [2] - https://www.youtube.com/watch?v=8jZDW53U8qQ https://www.youtube.com/watch?v=8jZDW53U8qQ
ChuckMcM 8y ago
Not that I get my science from SyFy but this particular hypothesis of a ice/dust composite doesn't survive the 'thermal / tidal' test. Which is that an object of that density would deform due to the tidal forces imparted by the Sun as it changed direction. I've yet to see a paper that suggests its profile changed at all before, during, or after the solar system transit.
- thebluehawk 8y ago
  We didn't detect it until it was leaving. So we have no data to compare to in order to even begin to speculate if it changed shape at its periapsis.
- joering2 8y ago
  In Oumuamua defense, it hasn't seen this much of Sun to be impressed or inflicted by its thermal power. 25. kilometers. per. second. It went in and out before Sun could do its damage. However, the idea of a porous surface like a snowflake or sponge or something doesn't add up because of exact speed it travels. Even if this is just ice/dust composite, with that kind of speed, it would be disintegrated by having its surface polished with cosmic energy long before it could reach 25km/s. I hope we won't see another one. This one was so close to Earth it wasn't funny. And traveled so quick we wouldn't have time to call all family members to tell them we love them. Its nothing like meteor; even big one would just drop flat on earth, raise all dust for next 30,000 years, throw us back into stone age or close to extinction and some form of human life looking nothing like we do today would argue 250,000 years from now what caused the first human near-extinction. No. You're talking about razor-sharp thin and lightweight object traveling with insane speed. Upon impact, it would either penetrate Earth surface exploding inside the core, like any hollow bullet does, or it would cut Earth in half like a high power laser and deform itself on way out. Either way this wouldn't be your near extinction experience. This would be like all of sudden Earth spliced in half and both parts going away, while you are either being drown with oceans hundreds feet of water tall due to lack of gravity, or crushed by weight of same ocean who happened to froze in the upper atmosphere, caught some gravity and smashed on the top of you. I don't want to even think about super hot lava thrown everywhere without gravity it would be like spraying venom from a giant snake. I have no idea how something like that would look like when Earth split in two, and no movies of that kind of extinction has ever been done. But something tells me it would be far from an easy death and I would rather carry on suicide pill in my tooth like they did during WW2, rather than witness such literal Hell on Earth.
slg 8y ago
I am just a layman, but it sounds like an object of this structure would be relatively fragile. Would it be able to survive the type of event that would be needed to launch it into interstellar space at the speed it is traveling?
- UncleEntity 8y ago
  If it does get a push from the sun's light it could reach escape velocity from its home sun in a few million rotations around it...maybe?
  - Symmetry 8y ago
    Normal solar pressure doesn't tend to speed up an object in its orbit since it comes in perpendicular to the direction of motion. However if the object is rotating it can absorb light on its inner side the re-emit it on its trailing side as that side cools down. This can alter orbits substantially over millions of years.
- Symmetry 8y ago
  That sort of event would typically be getting a slingshot[1] boost from a large passing mass. Those wouldn't come anywhere near breaking a normal asteroid but who knows with a fluffy one. [1]https://en.wikipedia.org/wiki/Gravity_assist https://en.wikipedia.org/wiki/Gravity_assist
- jandrese 8y ago
  If the object is a loose collection of dust it might very well be the result of something that didn't survive whatever event created it.
  - LeifCarrotson 8y ago
    What a tragedy that would be to catch it, find that it was created by some extrasolar intelligence, but it's been destroyed.
- egypturnash 8y ago
jl2718 8y ago
Meteorites form in distinctive nickel-iron crystal patterns (Widmanstatten). I wonder if they would form ‘snowflake’ patterns in conditions of large negative temperature and pressure gradient following a supernova shockwave.
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rayvd 8y ago
Makes me think of Rendezvous at Rama[1]. [1] https://en.wikipedia.org/wiki/Rendezvous_with_Rama https://en.wikipedia.org/wiki/Rendezvous_with_Rama
- mud_dauber 8y ago
  I came here for exactly this comment. Props.
doodlebugging 8y ago
So, an interstellar dust bunny. I wonder if it will find a resting place in some dark corner of the universe, maybe behind a black hole somewhere just out of our sight clinging tenuously to the outstretched arm of some far-off spiral galaxy and resisting every effort to slurp it back into the vacuum.
- Grimm665 8y ago
  Your comment made me smile.
  - doodlebugging 8y ago
    Thanks. It doesn't add much to the discussion but I thought at the time that it might be a reasonable analogy based on the author's speculations. Of course we may also have just missed the opportunity to save the Who's. Sadly though, they couldn't all yell loudly enough for us to hear them over here on our rocky speck.
    - rbanffy 8y ago
      Can we please name the space probe we'll launch to explore it "Dyson"? After Freeman Dyson, of course.
- camochameleon 8y ago
  "Interstellar dust bunny" is a fantastic phrase.
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eof 8y ago
I don't find the author's reasoning in the related article[1] that its not a solar sail very convincing. I am not an astrophysicist, but, the author plainly admits that the measurements are within expected bounds of a solar sail. Instead, the argument is surrounding the psychology of the hypothetical creators of said solar sail, or plausible ways we missed some data. Since we are just speculating at this point, who am I to say? But to answer some specific criticisms: - Perhaps the brightness/darkness cycles were the sail turning on and off as a mechanism to control velocity - Perhaps the 25km/s speed being a crawl for interstellar travel was because it was meant to slow down while passing through our solar system. Either so we might notice it, or so it can collect data while here a bit better. I am having a hard time understanding how rare an event this space-foam-fractal theory is predicting, but if it's extremely rare a solar sail seems a completely reasonable hypothesis still. 1. https://www.syfy.com/syfywire/is-oumuamua-an-interstellar-spaceship-im-still-going-with-no https://www.syfy.com/syfywire/is-oumuamua-an-interstellar-sp...
- dwaltrip 8y ago
  It's far more likely to be a poorly understood natural phenomenon that we will later make sense of. It would be the millionth example of that, compared with the _first ever_ example of life not from Earth (capable of building interstellar tech!). We need very, very strong evidence to overcome this hurdle. We know for a fact that the universe is filled with strange and interesting dynamics (not involving alien life forms) that we don't always understand at first. We don't yet know where else life may exist in the universe, if at all.
  - pbhjpbhj 8y ago
    Alien life would be a natural phenomenon, ultimately; on a deep analysis any phenomenon is natural. We make a differentiation between phenomenon wrought from cognition, but that cognition is - at least in part - a natural phenomenon too. Is this distinction founded in dualist philosophies(mind-body and/or material-spirit)? Does it make sense to make for monistic materialists? We might not ultimately recognise alien construction as coming from some intellect, plenty of creatures create structures on Earth (as do physical processes) with high complexity that are not considered to result from cognition.
Mizza 8y ago
What are the hypothetical requirements of a craft/probe which could be sent to chase after this object? Could we build something very small but extremely fast perform a fly-by? It kills me to think we've been visited by a mystery I'll never get the answer to in my lifetime.
- ldenneau 8y ago
  This was answered non-facetiously after discovery: https://arxiv.org/abs/1902.04935 https://arxiv.org/abs/1902.04935
- sp332 8y ago
  Yeah, it's slow enough that we could catch up to it. One of the biggest mysteries about it is why it was moving so slowly. Voyager left the solar system at 17,000 m/s. ‘Oumuamua accelerated to a top speed over 87,000 m/s as it was moving toward the sun, but it's slowing down now, and will eventually slow to 26,000 m/s. It will pass the orbit or Uranus early next year.
  - jandrese 8y ago
    Note that the Voyager probes are only moving that fast because they got orbital assists. It would take a very big rocket already in orbit to attempt an intercept.
    - sp332 8y ago
      Oh it would be crazy expensive. But we have the tech. (Wait, do we have tech for in-orbit refueling? Anyway we're developing that for Mars missions already so we'll have it soon.)
      - lucb1e 8y ago
        We resupply the international space station, so even if we couldn't carry great loads of fuel up at a time, orbital refueling is clearly within the realm of the possible. More interesting would be if we could beam up energy to refuel, but for that we'd probably need yet-to-be-invented drives which use loads of energy per amount of matter to accelerate it further. Kind of like a particle collider but for propulsion.
airstrike 8y ago
Fans of The Expanse have known what it is all along...
pjungwir 8y ago
Isn't extra acceleration what dark energy is supposed to explain? (Maybe "explain" is the wrong word. :-) I haven't seen anyone say this (probably for some good reason), but maybe 'Oumuamua's acceleration is from the same source? I'm curious what more knowledgeable people have to say about that.
- saagarjha 8y ago
  The "acceleration" dark energy is supposed to explain is with regards to the expansion of the universe, which would have very little effect on anything on scales this small.
- not_kurt_godel 8y ago
  Dark energy is an expansion of spacetime itself that is uniformly present throughout the entire universe. If it were responsible for ʻOumuamua's acceleration it would have been followed by our entire solar system being shredded down to subatomic particles shortly afterwards - see https://en.wikipedia.org/wiki/Big_Rip https://en.wikipedia.org/wiki/Big_Rip
LifeLiverTransp 8y ago
Seriously- its a snow-flake, as in something snow bally like Halley's Comet - that would emit vapours under light pressure? What is this, if you disprove your own thesis in the prelude of your article? Scientific slapstick?
- jandrese 8y ago
  Sounds like it might be a giant rock-dust flake. Maybe the whole thing is held together by vacuum welding?
  - jerf 8y ago
    If you imagine a dirty snowball, then sling it past a star so that all the ice melts and leaves, you might be left with something vacuum welded together, but very fluffy for its size. Perhaps the same time that it lost all its volatiles is also what ejected it from some system, a slingshot around some other star.
    - jandrese 8y ago
      That wouldn't be terribly different from how Aerogels are made.
Quequau 8y ago
OK this is great. I never gave a moment's credence to the idea that it was an alien spaceship but I really enjoyed reading the thoughtful and well reasoned arguments for and against the idea. For me the space of thought that these arguments created was an interesting experience that gave me an interesting perspective. So saying "hey no, it's not spaceship... it's weirder than that" (and then arguing that point) is fantastic.
- bgroins 8y ago
  Coming from a planet that launches a lot of alien spaceships, is it that implausible that it could be (or could have been) an alien spaceship?
  - xeonoex 8y ago
    This. I don't understand why articles like this are so quick to dismiss the chance that it was an alien probe or ship. I feel like it's just to get clicks and make the hypothesis they present seem more plausible. I totally agree that there is a good chance that it wasn't alien, and we want to identify what it could be if it wasn't, but why dismiss it? Most scientist already believe we are not alone, even though it is unlikely we are close to any other intelligent life. The chance that it was alien should be explored as well, and I know their are scientist who believe it is alien.
  - JBReefer 8y ago
    Huh, literally never thought of it that way. We put a ton of trash into space - someone is probably, at some point in the future, going to say "what the fuck is that" when Voyager goes flashing by!
  - Quequau 8y ago
    I guess after all these years Carl Sagan's observation still makes a lot of sense to me. Extraordinary claims demand extraordinary evidence. So far I've only seen ordinary and interesting evidence.
hooplaz 8y ago
Our team at UDT has been studying this object in partnership with Odlid observatory in Iceland, and we seem to have finally determined that it is in fact your mom's dildo.
dwighttk 8y ago
I feel like the headline writer tried to spice it up a bit and went too far. Seems much less weird than alien artifact to me. I mean I'd click on an "Another Oumauamua Theory" headline, but I guess that's not what kids are clicking on these days.
arxpoetica 8y ago
> It seems far more likely that objects like 'Oumuamua are relatively rare, and that means it likely came from someplace close by (if it came from farther away, the odds are even lower we'd ever see one). Rare enough to be a space ship?
- SahAssar 8y ago
  Given that we don't know if interstellar spaceships exist I'd say calling them "rare" is a misnomer.
kirykl 8y ago
Weird still is "Oumuamua's velocity (being) within 5 km/s of the median Galactic velocity of the stars in the solar neighborhood" (https://arxiv.org/abs/1710.11364 https://arxiv.org/abs/1710.11364) That means the system it originated from if a natural object would need to be coincidentally that close to our median local
gammateam 8y ago
This was an amazing deduction. I dont understand the key component of the article about the radiation from the sun giving it a boost. These scientists were able to make all these deductions about its shape and why from this, but what? How does radiation propel in any circumstance? Are we saying molecules change composition? Electrons moving to another state? What
- RPLong 8y ago
  This article explains that aspect of it: https://en.wikipedia.org/wiki/Solar_sail https://en.wikipedia.org/wiki/Solar_sail
- LyndsySimon 8y ago
  > How does radiation propel in any circumstance? It depends on the type of radiation, but two mechanisms jump to mind for me: The first is direct action of photons, as in a Crookes radiometer. The idea is that the black and white sides of the vanes respond to different types of EM radiation differently. How it actually works is somewhat beyond me (and apparently contentious), but it does work: https://en.wikipedia.org/wiki/Crookes_radiometer https://en.wikipedia.org/wiki/Crookes_radiometer The second is is through boiling. If the side of the object facing the sun were composed of a material that boiled when exposed to sunlight, the boiling off of that material would provide thrust against the object in the same way a rocket provides thrust (by expelling gas). Note that I am not a physicist, and am not proposing that either of these are the reason for the object's anomalous trajectory - just throwing out two ideas through which radiation could propel an object.
gammateam 8y ago
None of this rules out the idea that it is a vessel and or from a civilization Its not mutually exclusive Its just clever and now we have hypothesis about how it was done
apotatopot 8y ago
It's not fat, it's fluffy.
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mel919 8y ago
The whole situation of us encountering Oumuamua and being unable to gather much information about it reminds me of one of the Lem's short stories about Pilot Pirx in which he encounters an unique alien object and is also struggling with recording data about it. Here's a quote that works on imagination: There are times when the human eye can behave like a camera lens, when a momentarily but brilliantly cast image can be not merely recalled but meticulously reconstructed as vividly as if viewed in the present. Minutes later, I could still visualize the surface of that colossus in the flare’s afterglow, its kilometers-long sides not smooth but pocked, almost lunar in texture; the way the light had spilled over its corrugated rills, bumps, and craterlike cavities—scars of its interminable wandering, dark and dead as it had entered the nebulae, from which it had emerged centuries later, dust-eaten and ravaged by the myriad bombardments of cosmic erosion. I can’t explain my certainty, but I was sure that it sheltered no living soul, that it was a billion-year-old carcass, no more alive than the civilization that gave birth to it. This story (Pirx's Tale) is available on Google Books: https://books.google.com/books?id=n16z06cm1P0C&lpg=PT11&dq=%22Sci-fi%3F%20Sure%2C%20I%20like%20it%2C%20but%20only%20the%20trashy%20stuff.%22&pg=PT11#v=onepage&q=%22Sci-fi?%20Sure,%20I%20like%20it,%20but%20only%20the%20trashy%20stuff.%22&f=false https://books.google.com/books?id=n16z06cm1P0C&lpg=PT11&dq=%...
buboard 8y ago
But ... i thought amazon is going to produce the new series of the Expanse. Or is SYFY going to fork the story with a 'deuteromolecule' ?
siavosh 8y ago
Off topic, on the writing style: the personal casual style that sprinkles things with "I have to say, I love this." seems to have become incredibly common now in news sources. What's led to this? I always feel like it detracts from the story, and adds nothing unless they've AB tested it and it helps ad revenue?
- dogma1138 8y ago
  Discourse and language in general has seem to become “dumbed” down in the past 50 years.
- Brendinooo 8y ago
  This is a blog, right? Blogs have always been more informal.
- Zarath 8y ago
  The most irritating headlines to me are "No. XXX is not YYY."
dontbenebby 8y ago
One of the embedded assumptions I seem to see in discussions about this object is that objects like it (from outside the solar system) are rare. Is this truly the case, or is it just hard to monitor the paths of the multitude of objects passing by earth?
- tericho 8y ago
  It is rare because other systems that form these objects are VERY far away (trillions of KMs). Imagine trying to slide a hockey puck from one end of a hockey rink to the other, but have it pass through a small (~1M) circle at the far end from you. If you took 1000 attempts even randomly, you'd probably hit the circle by accident at some point. Now someone else is also shooting at the circle, but they are 50,000KM away. Suffice to say no matter how many attempts that person takes, it will be significantly more rare to see their puck cross through the circle than yours.
Jeff_Brown 8y ago
The argument "it's too slow to be a spaceship" makes a lot of unstated economic assumptions. Yes, a bigger sail would be faster. But if you wanted to send a lot of ships to various places, and you were the kind of civilization that makes very long-term investments, smaller probes could be optimal.
fizixer 8y ago
paper: > [Oumuamua as a fractal] is a hypothesis worth investigating ... tabloid journalists: > NO, 'OUMUAMUA IS NOT AN ALIEN SPACESHIP ... I guess the use of 'Bad Astronomy' tag is apt.
jimijazz 8y ago
Is it technically correct to call 'Oumuamua an UFO? I mean, it is unidentified so it should apply, right?
- rbanffy 8y ago
  Considering its trajectory is more or less ballistic, the F would stand for "Falling".
darklighter 8y ago
This is ridiculous. It’s intergalactic debris, it could be anything. I would prefer to see a list of things it could be vs. the hubristic response of leading scientists. It’s a great example of something unknown.
- zapzupnz 8y ago
  > I would prefer to see a list of things it could be vs. the hubristic response of leading scientists But isn't it through what leading scientists deem it could be that we get such a list that you want? Otherwise, it could be: - an icy fractal aggregate - a rock - a teapot - a bunny rabbit - a full-scale replica of the Titanic visible only to bees - a fortnight's holiday in Benidorm
Pristina 8y ago
It's probably an alien probe disguised as a random rock. It's already transmitted the existence of Earth and its coordinate back to the homeworld. Soon a supernuke will be sent at 0.99C to nip humanity in the bud.
booleandilemma 8y ago
It frustrates me to no end that there was a possibility (however small) that we could have witnessed an alien artifact passing by our planet and we missed it.
elizabeth_olu 8y ago
www.elizabethblog.com.ng
jypepin 8y ago
Ok, I know nothing about space, but looking at this video, it makes me realise something. Would have it been possible for thie Oumuamua to directly crash into the sun and just... end our solar system? Just like that?
- Tepix 8y ago
  Why would a tiny object crashing into a star "end" the solar system?
- Cthulhu_ 8y ago
  I guess it would be possible that it crashed into the sun, if it had the right trajectory, but it wouldn't have had any effect; the thing is 50 - 130 meters, while the sun is nearly 900.000 KILOmeters in diameter. It would likely have burned up before even reaching the surface of the sun. Even if it was idk, a huge nuclear weapon that detonated before melting, it wouldn't matter because the sun already is a huge fusion nuke. It does coronal mass ejections regularly that, according to a pop sci article I just read, already has more energy than 20 million nuclear weapons - anything that would end the sun would have to be several orders of magnitude stronger.
- LeifCarrotson 8y ago
  As Douglas Adams wrote: > Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space. An image which accurately shows both the Sun and other objects to size or at the correct distance doesn't give you an accurate measure of scale. Movies which show space sequences and ships flying from one planet to the other don't help, either. An image of the Solar System which shows both the Earth and Sun in the same image is either distorting the size of the Earth, distorting the distance between the two, or both. Here's one tool that may help...get your scroll wheel warmed up, though: http://joshworth.com/dev/pixelspace/pixelspace_solarsystem.html http://joshworth.com/dev/pixelspace/pixelspace_solarsystem.h... Or maybe you could visit one of the many to-scale solar system models, and take a walk from a 1-meter-diameter sun 100 meters away to a 1-cm-diameter Earth and continue walking for 30 minutes to the outer planets. At 1 meter scale for the Sun, Oumuamua is 0.1 microns, or 1/10th the size of a bacteria. If we multiply everything by 10,000 until the object is a 1mm grain of rice, now the Sun is 10 km in diameter, the size of a small city. Nothing the grain of rice could do, no matter how fast it moves or what it's made of, would harm the city-sized ball of fire. Granted, a 130 meter high-density (not Oumuamua) high-velocity asteroid impacting the Earth (100 meter diameter in our scaled-up rice-grain model) would cause significant distress for the very environmentally sensitive organisms clinging in a thin film to its surface (namely, humans), especially near the impact site.
DoctorOetker 8y ago
what I don't understand is this: if the kinetic energy is higher than the potential energy, what is the probability that it would pass the sun so closely? for bound objects this is not so surprising. either these objects are way more frequent than we think and the reason it passed the sun so closely was simply that these would be the first to be observed, or it almost seems aimed to pass the sun closely?
- yesenadam 8y ago
  We do think they're very 'frequent': "Astronomers estimate that several interstellar objects of extrasolar origin (like ‘Oumuamua) pass inside the orbit of Earth each year, and that 10,000 are passing inside the orbit of Neptune on any given day." https://en.wikipedia.org/wiki/%CA%BBOumuamua#Other_interstellar_objects https://en.wikipedia.org/wiki/%CA%BBOumuamua#Other_interstel...
billbrown 8y ago
The main proponent of the Oumuamua is an extra-solar object is Harvard astronomer Avi Loeb and there's a great interview with him where he discusses his reasons for his conclusions in a very accessible manner: https://after-on.com/episodes-31-60/040 https://after-on.com/episodes-31-60/040
dkonofalski 8y ago
So... in the time in the US where both sides are yelling at each other about being special snowflakes, we have the largest snowflake ever observed just floating by. What a weird coincidence and what a time to be alive!
sandymcmurray 8y ago
Disk Not Ejected Properly Eject "Oumuamua" before disconnecting or turning it off.

509 points by Santosh83 8y ago

At least this makes sense. Perhaps calling it a fractal is an unnecessary spin, but if it is linbaity enough to cover the spaceship theory I'm in. More than a fractal, it is better to imagine it as a pile of recently fallen snow is a day with the correct climate (cold?), so the snow accumulates but it doesn't compact too much. So the density is much smaller than the density of ice that has been in a glaciar for years under a lot of pressure. Since the gravity is too low, it will no compact too much. The main difference is that it's not a pile of real snowflakes, ut a pile of dust "snowflakes". Otherwise, the ice in the real snowflakes would have been partially evaporated by the sun and it will be classified as a comet. Anyway, it would be interesting to read more technical details about the plausibility of this. Can the dust pile survive the micrometeorites? Does the color profile match a dust pile object. I really don't like the starship hypothesis paper, but at least it contains a good analysis of many of the (secondary) objections.

sandworm101 8y ago
And can that loose pile of dust survive even a slight rotation. If it is long and thin, the dust near the tips should separate.
- gmueckl 8y ago
  There are mechanisms by which tiny particles may bond over time without becoming more dense. The only prerequisite is that individual atoms or molecules can move on the surface of the particles. This is true for a wide range of conditions, but usually is extremely slow.
- acqq 8y ago
  The article claims that if it has the snowflake properties it isn’t long and thin and still produces what we saw.
jerf 8y ago
"Perhaps calling it a fractal is an unnecessary spin," It is, or at least calling it self-similar is, as well as what the image implies: https://www.youtube.com/watch?v=gB9n2gHsHN4 https://www.youtube.com/watch?v=gB9n2gHsHN4 That's a 3Blue1Brown video explaining why "fractal" and "self-similar" are not the same thing.
- gowld 8y ago
  That video is about how "self-similar" is not sufficient for fractal. (The rest of the requirement is some notion of fine detail at every scale, which the video focuses on.) It is widely agreed that self-similarity is required for fractal, although often interpreted as quasi/statistical/multiple similarity https://en.wikipedia.org/wiki/Fractal https://en.wikipedia.org/wiki/Fractal Put another way, some things are self-similar but lack detail (for example, a straight line), and some things have detail but not similar detail at all scales (for example, a meterstick with ticks at every millimeter) and some things have infinite detail but no similarity (for example, purely entropic noise that cannot be compressed or expressed as a structure)
  - karmakaze 8y ago
    The core idea of a fractal is something having fractional dimension. It just happens that the ones we know of are self-similar. If we had a formula that generated different shapes ad infinitum, I would also call that a fractal.
  - jerf 8y ago
    It may be "self-similar" in a particular mathematical way, but fractal does not imply "self-similar" in the way people expect.
  - aoeusnth1 8y ago
    I think you meant "not necessary".
Gibbon1 8y ago
> Perhaps calling it a fractal is an unnecessary spin It's a GIANT INTERSTELLAR DUST BUNNY!!! slinks away
gene-h 8y ago
It makes more sense to call it a fractal rather than a pile. In the paper they reference, it is suggested that particles can form fractal like structures through a diffusion limited aggregation process[0]. One very important result in planetary science is the observation by the astronaut Donald Pettit of granular materials aggregating together in microgravity[1]* . In the experiment[2], it appears that some of the resulting structures resemble those formed in a diffusion limited aggregation process. *It is also worth noting that this experiment was entirely ad-hoc and came about from Don basically just playing around with stuff in microgravity [0]https://arxiv.org/pdf/1402.7132.pdf https://arxiv.org/pdf/1402.7132.pdf [1]https://www.lpi.usra.edu/meetings/lpsc2004/pdf/1119.pdf https://www.lpi.usra.edu/meetings/lpsc2004/pdf/1119.pdf [2]https://www.youtube.com/watch?v=k0YuivnCXhM https://www.youtube.com/watch?v=k0YuivnCXhM
- borkt 8y ago
  For example, bismuth crystals grow in an interesting way and, like h20 are less dense as a solid than a liquid. At the utterly extreme temperature/pressure environments expereinced in the universe, it isn't hard to believe there are solids out there we can't begin to predict at present. Below are some 3D crystal growths at SEM and macro scales for earth examples https://i.pinimg.com/originals/5d/bf/9c/5dbf9caa3ece888f2dc2f3b24bb0673f.jpg https://i.pinimg.com/originals/5d/bf/9c/5dbf9caa3ece888f2dc2... https://www.doitpoms.ac.uk/miclib/micrograph_record.php?id=617 https://www.doitpoms.ac.uk/miclib/micrograph_record.php?id=6...
jcoffland 8y ago
> More than a fractal, it is better to imagine it as a pile of recently fallen snow But snow flakes are fractals.
- lippel82 8y ago
  But a pile of snow is not.
- qubex 8y ago
  And snow ‘falls’ in gravity. This aggregated somehow else.maybe by tenuous electrostatic attraction (some ice particles get positively ionized when a photo kicks out an electron, some get negatively ionized when an electron attaches to them, & cetera and eventually they clump together to make a roughly electrical neutral object. The. Hydrogen bonds kick in once it’s electrically neutral (assuming it’s made of water or other polar molecules).
  - philipov 8y ago
    Why does it have to be something else? Couldn't the particles have precipitated gravitationally inside a smallish dust cloud?
lallysingh 8y ago
It's Wired. They have to use "fractal" a few times an issue or their articles of incorporation call for a new board.
- eric_h 8y ago
  It’s Phil Plait on the Syfy blog Bad Astronomer, not Wired. He does occasionally get a bit click-baity in his headlines but the content is pretty solid, particularly on the subject of omuamua
  - lallysingh 8y ago
    Oh wow, you're right. I saw the green-underlined all-caps text and assumed Wired. That and the word fractal.
- qubex 8y ago
  Funny you mention that. I seem to remember them classifying it as a “meme that died from overexposure” in their regular feature sometime back in 1997 or thereabouts.

excalibur 8y ago

I don't know that this theory is any "weirder" than an alien spacecraft, but it's certainly more plausible.

roberttod 8y ago
I can't see how it's anywhere near as weird as an alien spacecraft. Interesting article though.
arxpoetica 8y ago
Plausible or less deniable?

coolspot 8y ago

> Assuming a size for 'Oumuamua of 50 – 130 meters, what they get is a very low density: About 0.00005 grams per cc. Do we have example of naturally ocurring space object with such low density? Half-close? Quarter-close?

downer52 8y ago
There's a first time for everything, no?
deleted 8y ago
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privong 8y ago
> Do we have example of naturally ocurring space object with such low density? Depends what you mean by "object. Assuming the mass is mostly protons, that corresponds to a density of ~3e19 particles per cc. In comparison, molecular clouds in the galaxy have regions which are have densities as low as 1e2 particles per cc. And the hot X-ray emitting gas in clusters can be less than 1 particle per cc. There are things which span the gap, including disks around stars.
- jcriddle4 8y ago
  By object he is probably talking about matter in a solid state which would exclude gas or plasma. Also given Oumuamua's rotation rate the pieces of matter that makes up the object probably has to have some bounds with each other or it would fly apart.
Symmetry 8y ago
Even an aerogel is .0.2g/cc. That sounds implausible to me but so does the solar sail hypothesis. And really we don't have much information about what an interstellar object would be like.
- gus_massa 8y ago
  I agree that the proposed density is too low. Anyway, the aerogels are deigned to support their own weight on Earths, wind currents and some moron poking them. The magical aerogel of this object may have lower requirements.

27182818284 8y ago

The idea it is a fractal structure is not weirder than the idea it is possibly an alien probe sent over the course of hundreds of thousands of years to pass by our Goldilocks-zoned planet for observation. Does anyone know more about the initiatives by Yuri Milner with respect to this? I heard something like he is helping fund satellites that could specifically be better at looking at 'Oumuamua than our current means?

magduf 8y ago
We can't look at 'Oumuamua any more, with any kind of spacecraft. It's headed out of the solar system. There's absolutely no way we could possibly put together a mission and build a craft and launch it and have it catch up with 'Oumuamua at this point. If we had something ready to launch now, it might be possible to catch up with it, but it would be years before we could have a mission ready to go, and we don't have the propulsion technology necessary to catch up with it after that much time. This should have been a big wake-up call to have pre-made probe craft ready to launch to investigate anything odd that entered the solar system. But expecting humanity to be that fore-sighted is pure folly.
- LifeLiverTransp 8y ago
  We can foresee our lack of foresight- so its not hopeless.
  - magduf 8y ago
    I'm sure there were some people who could foresee the lack of foresight before the collapse of Rome too. It didn't help them.
- jandrese 8y ago
  Oumuamua is traveling at 26kps. For comparison the Voyager probes are traveling at around 17kps. Even if we had a probe ready today it's already too far and moving too fast to overtake. Even if we had a probe ready when we first detected the object it would have been difficult to intercept with today's technology. It would have to be something like a Falcon Heavy already in orbit and ready to burn at a moment's notice with a tiny probe at the top for gathering the data.

GlenTheMachine 8y ago

I'm curious about whether an object with a density this low could survive the gravity gradient it experienced during the solar flyby.

jefb 8y ago
As am I. The paper dedicates one sentence to that question: "... another aspect that needs to be studied is whether its extremely low density could be maintained while in the parent system, during its long interstellar journey, and when entering the solar system." Without analyzing the structural integrity of such a fluff ball it's tough to give any more or less merit to this concept than the others.
ars 8y ago
Unless it's very large why would there by much of a gravity gradient? It never came all that close to the sun, so the gradient on different parts of it wouldn't be that extreme.
- GlenTheMachine 8y ago
  There wouldn't be a large gradient. But a big ball o' fluff presumably has essentially no internal cohesion; it's sort of like a liquid in that way. So even very small gradient forces could be enough to disperse it.
  - ars 8y ago
    So lets run the numbers: At Perihelion it was 38198320 km from the sun = an acceleration of 0.090962666582226 m/s^2 It's 1km long so on the other end the acceleration is 0.090962661819574 m/s^2 Subtract: .000000004762652 m/s^2 which is such a small amount I'm not sure how to put it into context. Multiply by 1 metric ton = 1/5 weight-force of a single snowflake on earth. Which means each metric ton of material needs to handle just that much force trying to separate it. i.e. it won't be ripped apart in the slightest. Over centuries it might elongate a bit (and it's already elongated).

komali2 8y ago

> It seems far more likely that objects like 'Oumuamua are relatively rare, and that means it likely came from someplace close by (if it came from farther away, the odds are even lower we'd ever see one). Ok, it's on my list of things to do this year to actually learn how statistics work, but my naive reaction to this supposition, which I read is "the fact that we have encountered Oumuamua means that it's likely it didn't come from far away, because if it did, it's less likely we would have encountered it," is: We did encounter it. Just this one, ever. How can we draw any statistical information from that? Either we encountered it, or didn't, how does that have any bearing on the statistical probability of seeing it?

nerbert 8y ago
We did encounter it during the short timeframe in which we would be able to detect it. Could be a once every 20 years occurrence, that would make it quite frequent.
azeirah 8y ago
I don't know much about statistics, but I can add that the time period matters. If we only started observing space yesterday, and saw it, it would be weird to say "it's rare", but we've been observing space for, I don't know, up to 400 years? (counting since invention of telescope, 1608)
- nkrisc 8y ago
  I don't think an object like this could have been spotted until relatively recently.
- polityagent 8y ago
  But how recently have we developed the capability to: - observe this thing at all - accurately measure it's velocity and acceleration - understand that it's velocity and acceleration were unusual?
- KineticLensman 8y ago
  > but we've been observing space for, I don't know, up to 400 years? (counting since invention of telescope, 1608) We've been observing space 'forever'. Pre-telescope observers had quite accurate star maps (of the naked-eye stars, obviously) and were fully aware of the complex movements of the planets. Their models of the movements were good enough for predictions even if the underlying explanatory causal models were sometimes wrong.

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crispyambulance 8y ago

No one can say for certain what Oumuamua actually is-- other than it is "a surprise". What it really is, IMHO, is a call to action for better instrumentation so that the next time one of these things pays us "a visit", we're in a position to find out more about it.

gammateam 8y ago
Solar Defense Force!
rjf72 8y ago
And better rocket come 'space ship' preparedness. You can only learn so much about things from millions of miles away regardless of your resolution. It's a very serious problem that our space program has severely regressed. In 1969 we put men on the moon and brought them back home safely. In 2019, we struggle to send a man on a flyby around the moon! It's frustrating because we already have the technology to be able to achieve basic intercepts here, even if they were at high velocity. The only thing in the way is a dilapidated space program.
- planteen 8y ago
  Manned exploration may have reached a zenith in 1969, but science did not. In 1969, the field of planetary science did not really yet exist. Since then, we have done flybys of every planet, intercepted comets and asteroids, put orbiters around many of them, landed probes on more, and even had robots driving around! A ton of science has happened since 1969.
  - rjf72 8y ago
    I would not disagree, though the Soviet Union had already put a probe within the atmosphere of Venus in 1967. In 1970 they landed a probe on its surface!! They were called the Venera [1] probes. They also returned audio and picture from the surface of Venus. Absolutely remarkable if you're never heard it before. This [2] is the sound of the probe coming down through Venus' atmosphere, its landing, the lens cap (for the camera) popping off, the deploying of the drill, and then the drilling of course. In my opinion that remains arguably the most remarkable achievement in planetary science in our solar system. Although it must be said that that audio came much later than the earlier probes. "Much later" being about 40 years ago. I think the recent discovery/confirmation that our moon has substantial reserves of water ice emphasizes the difficulties with technology outside of manned exploration. There's a lot of information you can obtain from probes and other forms of remote observation, but it tends to be extremely specialized and very limited. This is not something we should be discovering 40 years after landing on it -- water was confirmed in 2009. [1] - https://en.wikipedia.org/wiki/Venera https://en.wikipedia.org/wiki/Venera [2] - https://www.youtube.com/watch?v=8jZDW53U8qQ https://www.youtube.com/watch?v=8jZDW53U8qQ

ChuckMcM 8y ago

Not that I get my science from SyFy but this particular hypothesis of a ice/dust composite doesn't survive the 'thermal / tidal' test. Which is that an object of that density would deform due to the tidal forces imparted by the Sun as it changed direction. I've yet to see a paper that suggests its profile changed at all before, during, or after the solar system transit.

thebluehawk 8y ago
We didn't detect it until it was leaving. So we have no data to compare to in order to even begin to speculate if it changed shape at its periapsis.
joering2 8y ago
In Oumuamua defense, it hasn't seen this much of Sun to be impressed or inflicted by its thermal power. 25. kilometers. per. second. It went in and out before Sun could do its damage. However, the idea of a porous surface like a snowflake or sponge or something doesn't add up because of exact speed it travels. Even if this is just ice/dust composite, with that kind of speed, it would be disintegrated by having its surface polished with cosmic energy long before it could reach 25km/s. I hope we won't see another one. This one was so close to Earth it wasn't funny. And traveled so quick we wouldn't have time to call all family members to tell them we love them. Its nothing like meteor; even big one would just drop flat on earth, raise all dust for next 30,000 years, throw us back into stone age or close to extinction and some form of human life looking nothing like we do today would argue 250,000 years from now what caused the first human near-extinction. No. You're talking about razor-sharp thin and lightweight object traveling with insane speed. Upon impact, it would either penetrate Earth surface exploding inside the core, like any hollow bullet does, or it would cut Earth in half like a high power laser and deform itself on way out. Either way this wouldn't be your near extinction experience. This would be like all of sudden Earth spliced in half and both parts going away, while you are either being drown with oceans hundreds feet of water tall due to lack of gravity, or crushed by weight of same ocean who happened to froze in the upper atmosphere, caught some gravity and smashed on the top of you. I don't want to even think about super hot lava thrown everywhere without gravity it would be like spraying venom from a giant snake. I have no idea how something like that would look like when Earth split in two, and no movies of that kind of extinction has ever been done. But something tells me it would be far from an easy death and I would rather carry on suicide pill in my tooth like they did during WW2, rather than witness such literal Hell on Earth.

slg 8y ago

I am just a layman, but it sounds like an object of this structure would be relatively fragile. Would it be able to survive the type of event that would be needed to launch it into interstellar space at the speed it is traveling?

UncleEntity 8y ago
If it does get a push from the sun's light it could reach escape velocity from its home sun in a few million rotations around it...maybe?
- Symmetry 8y ago
  Normal solar pressure doesn't tend to speed up an object in its orbit since it comes in perpendicular to the direction of motion. However if the object is rotating it can absorb light on its inner side the re-emit it on its trailing side as that side cools down. This can alter orbits substantially over millions of years.
Symmetry 8y ago
That sort of event would typically be getting a slingshot[1] boost from a large passing mass. Those wouldn't come anywhere near breaking a normal asteroid but who knows with a fluffy one. [1]https://en.wikipedia.org/wiki/Gravity_assist https://en.wikipedia.org/wiki/Gravity_assist
jandrese 8y ago
If the object is a loose collection of dust it might very well be the result of something that didn't survive whatever event created it.
- LeifCarrotson 8y ago
  What a tragedy that would be to catch it, find that it was created by some extrasolar intelligence, but it's been destroyed.
egypturnash 8y ago

jl2718 8y ago

Meteorites form in distinctive nickel-iron crystal patterns (Widmanstatten). I wonder if they would form ‘snowflake’ patterns in conditions of large negative temperature and pressure gradient following a supernova shockwave.

deleted 8y ago

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rayvd 8y ago

Makes me think of Rendezvous at Rama[1]. [1] https://en.wikipedia.org/wiki/Rendezvous_with_Rama https://en.wikipedia.org/wiki/Rendezvous_with_Rama

mud_dauber 8y ago
I came here for exactly this comment. Props.

doodlebugging 8y ago

So, an interstellar dust bunny. I wonder if it will find a resting place in some dark corner of the universe, maybe behind a black hole somewhere just out of our sight clinging tenuously to the outstretched arm of some far-off spiral galaxy and resisting every effort to slurp it back into the vacuum.

Grimm665 8y ago
Your comment made me smile.
- doodlebugging 8y ago
  Thanks. It doesn't add much to the discussion but I thought at the time that it might be a reasonable analogy based on the author's speculations. Of course we may also have just missed the opportunity to save the Who's. Sadly though, they couldn't all yell loudly enough for us to hear them over here on our rocky speck.
  - rbanffy 8y ago
    Can we please name the space probe we'll launch to explore it "Dyson"? After Freeman Dyson, of course.
camochameleon 8y ago
"Interstellar dust bunny" is a fantastic phrase.

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eof 8y ago

I don't find the author's reasoning in the related article[1] that its not a solar sail very convincing. I am not an astrophysicist, but, the author plainly admits that the measurements are within expected bounds of a solar sail. Instead, the argument is surrounding the psychology of the hypothetical creators of said solar sail, or plausible ways we missed some data. Since we are just speculating at this point, who am I to say? But to answer some specific criticisms: - Perhaps the brightness/darkness cycles were the sail turning on and off as a mechanism to control velocity - Perhaps the 25km/s speed being a crawl for interstellar travel was because it was meant to slow down while passing through our solar system. Either so we might notice it, or so it can collect data while here a bit better. I am having a hard time understanding how rare an event this space-foam-fractal theory is predicting, but if it's extremely rare a solar sail seems a completely reasonable hypothesis still. 1. https://www.syfy.com/syfywire/is-oumuamua-an-interstellar-spaceship-im-still-going-with-no https://www.syfy.com/syfywire/is-oumuamua-an-interstellar-sp...

dwaltrip 8y ago
It's far more likely to be a poorly understood natural phenomenon that we will later make sense of. It would be the millionth example of that, compared with the _first ever_ example of life not from Earth (capable of building interstellar tech!). We need very, very strong evidence to overcome this hurdle. We know for a fact that the universe is filled with strange and interesting dynamics (not involving alien life forms) that we don't always understand at first. We don't yet know where else life may exist in the universe, if at all.
- pbhjpbhj 8y ago
  Alien life would be a natural phenomenon, ultimately; on a deep analysis any phenomenon is natural. We make a differentiation between phenomenon wrought from cognition, but that cognition is - at least in part - a natural phenomenon too. Is this distinction founded in dualist philosophies(mind-body and/or material-spirit)? Does it make sense to make for monistic materialists? We might not ultimately recognise alien construction as coming from some intellect, plenty of creatures create structures on Earth (as do physical processes) with high complexity that are not considered to result from cognition.

Mizza 8y ago

What are the hypothetical requirements of a craft/probe which could be sent to chase after this object? Could we build something very small but extremely fast perform a fly-by? It kills me to think we've been visited by a mystery I'll never get the answer to in my lifetime.

ldenneau 8y ago
This was answered non-facetiously after discovery: https://arxiv.org/abs/1902.04935 https://arxiv.org/abs/1902.04935
sp332 8y ago
Yeah, it's slow enough that we could catch up to it. One of the biggest mysteries about it is why it was moving so slowly. Voyager left the solar system at 17,000 m/s. ‘Oumuamua accelerated to a top speed over 87,000 m/s as it was moving toward the sun, but it's slowing down now, and will eventually slow to 26,000 m/s. It will pass the orbit or Uranus early next year.
- jandrese 8y ago
  Note that the Voyager probes are only moving that fast because they got orbital assists. It would take a very big rocket already in orbit to attempt an intercept.
  - sp332 8y ago
    Oh it would be crazy expensive. But we have the tech. (Wait, do we have tech for in-orbit refueling? Anyway we're developing that for Mars missions already so we'll have it soon.)
    - lucb1e 8y ago
      We resupply the international space station, so even if we couldn't carry great loads of fuel up at a time, orbital refueling is clearly within the realm of the possible. More interesting would be if we could beam up energy to refuel, but for that we'd probably need yet-to-be-invented drives which use loads of energy per amount of matter to accelerate it further. Kind of like a particle collider but for propulsion.

airstrike 8y ago

Fans of The Expanse have known what it is all along...

pjungwir 8y ago

Isn't extra acceleration what dark energy is supposed to explain? (Maybe "explain" is the wrong word. :-) I haven't seen anyone say this (probably for some good reason), but maybe 'Oumuamua's acceleration is from the same source? I'm curious what more knowledgeable people have to say about that.

saagarjha 8y ago
The "acceleration" dark energy is supposed to explain is with regards to the expansion of the universe, which would have very little effect on anything on scales this small.
not_kurt_godel 8y ago
Dark energy is an expansion of spacetime itself that is uniformly present throughout the entire universe. If it were responsible for ʻOumuamua's acceleration it would have been followed by our entire solar system being shredded down to subatomic particles shortly afterwards - see https://en.wikipedia.org/wiki/Big_Rip https://en.wikipedia.org/wiki/Big_Rip

LifeLiverTransp 8y ago

Seriously- its a snow-flake, as in something snow bally like Halley's Comet - that would emit vapours under light pressure? What is this, if you disprove your own thesis in the prelude of your article? Scientific slapstick?

jandrese 8y ago
Sounds like it might be a giant rock-dust flake. Maybe the whole thing is held together by vacuum welding?
- jerf 8y ago
  If you imagine a dirty snowball, then sling it past a star so that all the ice melts and leaves, you might be left with something vacuum welded together, but very fluffy for its size. Perhaps the same time that it lost all its volatiles is also what ejected it from some system, a slingshot around some other star.
  - jandrese 8y ago
    That wouldn't be terribly different from how Aerogels are made.

Quequau 8y ago

OK this is great. I never gave a moment's credence to the idea that it was an alien spaceship but I really enjoyed reading the thoughtful and well reasoned arguments for and against the idea. For me the space of thought that these arguments created was an interesting experience that gave me an interesting perspective. So saying "hey no, it's not spaceship... it's weirder than that" (and then arguing that point) is fantastic.

bgroins 8y ago
Coming from a planet that launches a lot of alien spaceships, is it that implausible that it could be (or could have been) an alien spaceship?
- xeonoex 8y ago
  This. I don't understand why articles like this are so quick to dismiss the chance that it was an alien probe or ship. I feel like it's just to get clicks and make the hypothesis they present seem more plausible. I totally agree that there is a good chance that it wasn't alien, and we want to identify what it could be if it wasn't, but why dismiss it? Most scientist already believe we are not alone, even though it is unlikely we are close to any other intelligent life. The chance that it was alien should be explored as well, and I know their are scientist who believe it is alien.
- JBReefer 8y ago
  Huh, literally never thought of it that way. We put a ton of trash into space - someone is probably, at some point in the future, going to say "what the fuck is that" when Voyager goes flashing by!
- Quequau 8y ago
  I guess after all these years Carl Sagan's observation still makes a lot of sense to me. Extraordinary claims demand extraordinary evidence. So far I've only seen ordinary and interesting evidence.

hooplaz 8y ago

Our team at UDT has been studying this object in partnership with Odlid observatory in Iceland, and we seem to have finally determined that it is in fact your mom's dildo.

dwighttk 8y ago

I feel like the headline writer tried to spice it up a bit and went too far. Seems much less weird than alien artifact to me. I mean I'd click on an "Another Oumauamua Theory" headline, but I guess that's not what kids are clicking on these days.

arxpoetica 8y ago

SahAssar 8y ago
Given that we don't know if interstellar spaceships exist I'd say calling them "rare" is a misnomer.

kirykl 8y ago

Weird still is "Oumuamua's velocity (being) within 5 km/s of the median Galactic velocity of the stars in the solar neighborhood" (https://arxiv.org/abs/1710.11364 https://arxiv.org/abs/1710.11364) That means the system it originated from if a natural object would need to be coincidentally that close to our median local

gammateam 8y ago

This was an amazing deduction. I dont understand the key component of the article about the radiation from the sun giving it a boost. These scientists were able to make all these deductions about its shape and why from this, but what? How does radiation propel in any circumstance? Are we saying molecules change composition? Electrons moving to another state? What

RPLong 8y ago
This article explains that aspect of it: https://en.wikipedia.org/wiki/Solar_sail https://en.wikipedia.org/wiki/Solar_sail
LyndsySimon 8y ago
> How does radiation propel in any circumstance? It depends on the type of radiation, but two mechanisms jump to mind for me: The first is direct action of photons, as in a Crookes radiometer. The idea is that the black and white sides of the vanes respond to different types of EM radiation differently. How it actually works is somewhat beyond me (and apparently contentious), but it does work: https://en.wikipedia.org/wiki/Crookes_radiometer https://en.wikipedia.org/wiki/Crookes_radiometer The second is is through boiling. If the side of the object facing the sun were composed of a material that boiled when exposed to sunlight, the boiling off of that material would provide thrust against the object in the same way a rocket provides thrust (by expelling gas). Note that I am not a physicist, and am not proposing that either of these are the reason for the object's anomalous trajectory - just throwing out two ideas through which radiation could propel an object.

gammateam 8y ago

None of this rules out the idea that it is a vessel and or from a civilization Its not mutually exclusive Its just clever and now we have hypothesis about how it was done

apotatopot 8y ago

It's not fat, it's fluffy.

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mel919 8y ago

The whole situation of us encountering Oumuamua and being unable to gather much information about it reminds me of one of the Lem's short stories about Pilot Pirx in which he encounters an unique alien object and is also struggling with recording data about it. Here's a quote that works on imagination: There are times when the human eye can behave like a camera lens, when a momentarily but brilliantly cast image can be not merely recalled but meticulously reconstructed as vividly as if viewed in the present. Minutes later, I could still visualize the surface of that colossus in the flare’s afterglow, its kilometers-long sides not smooth but pocked, almost lunar in texture; the way the light had spilled over its corrugated rills, bumps, and craterlike cavities—scars of its interminable wandering, dark and dead as it had entered the nebulae, from which it had emerged centuries later, dust-eaten and ravaged by the myriad bombardments of cosmic erosion. I can’t explain my certainty, but I was sure that it sheltered no living soul, that it was a billion-year-old carcass, no more alive than the civilization that gave birth to it. This story (Pirx's Tale) is available on Google Books: https://books.google.com/books?id=n16z06cm1P0C&lpg=PT11&dq=%22Sci-fi%3F%20Sure%2C%20I%20like%20it%2C%20but%20only%20the%20trashy%20stuff.%22&pg=PT11#v=onepage&q=%22Sci-fi?%20Sure,%20I%20like%20it,%20but%20only%20the%20trashy%20stuff.%22&f=false https://books.google.com/books?id=n16z06cm1P0C&lpg=PT11&dq=%...

buboard 8y ago

But ... i thought amazon is going to produce the new series of the Expanse. Or is SYFY going to fork the story with a 'deuteromolecule' ?

siavosh 8y ago

Off topic, on the writing style: the personal casual style that sprinkles things with "I have to say, I love this." seems to have become incredibly common now in news sources. What's led to this? I always feel like it detracts from the story, and adds nothing unless they've AB tested it and it helps ad revenue?

dogma1138 8y ago
Discourse and language in general has seem to become “dumbed” down in the past 50 years.
Brendinooo 8y ago
This is a blog, right? Blogs have always been more informal.
Zarath 8y ago
The most irritating headlines to me are "No. XXX is not YYY."

dontbenebby 8y ago

One of the embedded assumptions I seem to see in discussions about this object is that objects like it (from outside the solar system) are rare. Is this truly the case, or is it just hard to monitor the paths of the multitude of objects passing by earth?

tericho 8y ago
It is rare because other systems that form these objects are VERY far away (trillions of KMs). Imagine trying to slide a hockey puck from one end of a hockey rink to the other, but have it pass through a small (~1M) circle at the far end from you. If you took 1000 attempts even randomly, you'd probably hit the circle by accident at some point. Now someone else is also shooting at the circle, but they are 50,000KM away. Suffice to say no matter how many attempts that person takes, it will be significantly more rare to see their puck cross through the circle than yours.

Jeff_Brown 8y ago

The argument "it's too slow to be a spaceship" makes a lot of unstated economic assumptions. Yes, a bigger sail would be faster. But if you wanted to send a lot of ships to various places, and you were the kind of civilization that makes very long-term investments, smaller probes could be optimal.

fizixer 8y ago

paper: > [Oumuamua as a fractal] is a hypothesis worth investigating ... tabloid journalists: > NO, 'OUMUAMUA IS NOT AN ALIEN SPACESHIP ... I guess the use of 'Bad Astronomy' tag is apt.

jimijazz 8y ago

Is it technically correct to call 'Oumuamua an UFO? I mean, it is unidentified so it should apply, right?

rbanffy 8y ago
Considering its trajectory is more or less ballistic, the F would stand for "Falling".

darklighter 8y ago

This is ridiculous. It’s intergalactic debris, it could be anything. I would prefer to see a list of things it could be vs. the hubristic response of leading scientists. It’s a great example of something unknown.

zapzupnz 8y ago
> I would prefer to see a list of things it could be vs. the hubristic response of leading scientists But isn't it through what leading scientists deem it could be that we get such a list that you want? Otherwise, it could be: - an icy fractal aggregate - a rock - a teapot - a bunny rabbit - a full-scale replica of the Titanic visible only to bees - a fortnight's holiday in Benidorm

Pristina 8y ago

It's probably an alien probe disguised as a random rock. It's already transmitted the existence of Earth and its coordinate back to the homeworld. Soon a supernuke will be sent at 0.99C to nip humanity in the bud.

booleandilemma 8y ago

It frustrates me to no end that there was a possibility (however small) that we could have witnessed an alien artifact passing by our planet and we missed it.

elizabeth_olu 8y ago

www.elizabethblog.com.ng

jypepin 8y ago

Ok, I know nothing about space, but looking at this video, it makes me realise something. Would have it been possible for thie Oumuamua to directly crash into the sun and just... end our solar system? Just like that?

Tepix 8y ago
Why would a tiny object crashing into a star "end" the solar system?
Cthulhu_ 8y ago
I guess it would be possible that it crashed into the sun, if it had the right trajectory, but it wouldn't have had any effect; the thing is 50 - 130 meters, while the sun is nearly 900.000 KILOmeters in diameter. It would likely have burned up before even reaching the surface of the sun. Even if it was idk, a huge nuclear weapon that detonated before melting, it wouldn't matter because the sun already is a huge fusion nuke. It does coronal mass ejections regularly that, according to a pop sci article I just read, already has more energy than 20 million nuclear weapons - anything that would end the sun would have to be several orders of magnitude stronger.
LeifCarrotson 8y ago
As Douglas Adams wrote: > Space is big. Really big. You just won't believe how vastly, hugely, mind-bogglingly big it is. I mean, you may think it's a long way down the road to the chemist, but that's just peanuts to space. An image which accurately shows both the Sun and other objects to size or at the correct distance doesn't give you an accurate measure of scale. Movies which show space sequences and ships flying from one planet to the other don't help, either. An image of the Solar System which shows both the Earth and Sun in the same image is either distorting the size of the Earth, distorting the distance between the two, or both. Here's one tool that may help...get your scroll wheel warmed up, though: http://joshworth.com/dev/pixelspace/pixelspace_solarsystem.html http://joshworth.com/dev/pixelspace/pixelspace_solarsystem.h... Or maybe you could visit one of the many to-scale solar system models, and take a walk from a 1-meter-diameter sun 100 meters away to a 1-cm-diameter Earth and continue walking for 30 minutes to the outer planets. At 1 meter scale for the Sun, Oumuamua is 0.1 microns, or 1/10th the size of a bacteria. If we multiply everything by 10,000 until the object is a 1mm grain of rice, now the Sun is 10 km in diameter, the size of a small city. Nothing the grain of rice could do, no matter how fast it moves or what it's made of, would harm the city-sized ball of fire. Granted, a 130 meter high-density (not Oumuamua) high-velocity asteroid impacting the Earth (100 meter diameter in our scaled-up rice-grain model) would cause significant distress for the very environmentally sensitive organisms clinging in a thin film to its surface (namely, humans), especially near the impact site.

DoctorOetker 8y ago

what I don't understand is this: if the kinetic energy is higher than the potential energy, what is the probability that it would pass the sun so closely? for bound objects this is not so surprising. either these objects are way more frequent than we think and the reason it passed the sun so closely was simply that these would be the first to be observed, or it almost seems aimed to pass the sun closely?

yesenadam 8y ago
We do think they're very 'frequent': "Astronomers estimate that several interstellar objects of extrasolar origin (like ‘Oumuamua) pass inside the orbit of Earth each year, and that 10,000 are passing inside the orbit of Neptune on any given day." https://en.wikipedia.org/wiki/%CA%BBOumuamua#Other_interstellar_objects https://en.wikipedia.org/wiki/%CA%BBOumuamua#Other_interstel...

billbrown 8y ago

The main proponent of the Oumuamua is an extra-solar object is Harvard astronomer Avi Loeb and there's a great interview with him where he discusses his reasons for his conclusions in a very accessible manner: https://after-on.com/episodes-31-60/040 https://after-on.com/episodes-31-60/040

dkonofalski 8y ago

So... in the time in the US where both sides are yelling at each other about being special snowflakes, we have the largest snowflake ever observed just floating by. What a weird coincidence and what a time to be alive!

sandymcmurray 8y ago

Disk Not Ejected Properly Eject "Oumuamua" before disconnecting or turning it off.