That Interstellar Asteroid is Pretty Strange. Could It Be…?

By Corey S. Powell | November 23, 2017 10:36 am
Illustration of `Oumuamua, the first-known interstellar asteroid. Its unusual shape and color offer cryptic clues about the nature of objects from other solar systems. (Credit: ESO/M. Kornmesser)

Illustration of `Oumuamua, the first-known interstellar asteroid. Its unusual shape and color offer cryptic clues about the nature of objects from other solar systems. The challenge now is to find more of these messengers from the stars. (Credit: ESO/M. Kornmesser)

It isn’t aliens. It’s never aliens.

That’s the only sensible answer whenever astronomers spot something truly weird in space. That unusual radio blip from the planet Ross 128b? Not aliens. Potential SETI signal SHGb02+14a? Not aliens. The mysterious ‘alien megastructure’ star? Probably not aliens, either. There are so many unexplored natural explanations for unusual phenomena, and so many ways to make errors, that the starting assumption has to be no, no, a thousand times no, it is not aliens.

Then astronomers observed `Oumuamua, the first known interstellar asteroid, as it raced out of the solar system. Its wildly elongated shape resembles that of a rocket stage or–even more enticingly–the interstellar ship from Arthur C. Clarke’s science-fiction novel Rendezvous with Rama. Soon sober-minded reporters (including this one) were exchanging curious messages: Could this ‘asteroid’ actually be an alien artifact? How would we know?

Deep breath. Let’s take this one step at a time. On October 19, the automated Pan-STARRS 1 telescope (which is primarily intended to scan the sky for potentially hazardous, Earth-approaching asteroids) detected an unusual object. It was originally regarded as a possible comet, catalogued as C/2017 U1. By the end of the month, though, astronomers could clearly see that it was something much more remarkable.

First, the ‘comet’ had no fuzz; it was clearly not a comet but rather a fast-moving asteroid. It got a new designation, A/2017 U1 (A for asteroid). Much more intriguing, though, was its orbit. It was moving past the sun on a hyperbolic path, a trajectory indicating that it originated from beyond our solar system. It got another new designation, introducing a naming scheme never used before: 1I/2017 U1 (I for interstellar).

The Pan-STARRS team quickly picked a more apt name for such an important object. It’s now known as `Oumuamua (pronounced ‘oh-oo-moo-ah-moo-a’), a Hawaiian word that translates roughly as ‘messenger from the distant past.’

‘Oumuamua came from the direction of Vega, and is now racing back out to interstellar space at 26 kilometers per second. (Credit: ESO/K. Meech et al)

‘Oumuamua came from the direction of Vega. It’s now racing back out to interstellar space at 26 kilometers per second. (Credit: ESO/K. Meech et al)

Researchers had long theorized that space should be full of comets and asteroids ejected from other solar systems during their early days. Their models showed that planetary formation is a messy business, with many small objects kicked out as big proto-planets form. `Oumuamua is the first proof that they were right. It’s also our first direct look at an intact visitor (as opposed to dust specks) from another solar system.

We didn’t get much of a chance to study it, unfortunately. By the time `Oumuamua was discovered it was already past the sun, on its way back to the stars and off into the darkness. Astronomers at the world’s major observatories rushed to see what they could learn from it. They began amazing, rapid-fire studies. And what they found was…rather odd.

`Oumuamua rotates rapidly, every 7.3 hours. As it spins, its brightness changes drastically, indicating a highly elongated shape. Karen Meech at the University of Hawaii’s Institute for Astronomy concluded that the asteroid is about 400 meters long but only one tenth as wide. It’s shaped like a fat cigar, or maybe more like a fire extinguisher–an apt point of comparison, since the asteroid is also very red, similar to some of the objects in our solar system’s distant Kuiper Belt but also broadly similar to some metallic asteroids.

Sharply varying brightness of `Oumuamua indicates a long, tubular shape. Like a more extreme version of known comets and asteroids some fictional starships. (Credit: ESO/K. Meech et al)

Sharply varying brightness of `Oumuamua indicates a thin, tubular shape, like a more extreme version of known comets and asteroids…or like some fictional starships. Dots indicate brightness measurements; white dashes show the modeled light curve for a object 10 times as long as it is wide. (Credit: ESO/K. Meech et al)

Those unexpected traits caught the attention of a number of armchair scientists on Twitter, especially after the European Southern Observatory released a pair of evocative (albeit highly speculative) illustrations of `Oumuamua, including the one at the top of this post. Several leading researchers got drawn into the conversation as well.

The thing doesn’t look natural. So here we are again: Could it be artificial? How would we know?

First, there could be the obvious giveaways. It might be emitting radio signals or some other artificially modulated form of radiation. (We didn’t see that.) It might adjust its course in some way. (We didn’t see any deviation from a normal gravitational path.) It might give off a heat signature indicating some kind of engine or internal energy source. (We didn’t see that either, although nobody has looked at `Oumuamua in the far infrared.)

Then the chatter moved on to more elusive speculations. Could this be a dead, abandoned spaceship? Could it perhaps be instrumented but not actively powered? Jason Wright from Penn State summarized some of the conversation in a helpful, nicely skeptical blog post.

There are so many ET ideas to consider that it’s impossible to state with complete certainty that `Oumuamua is not somehow associated with an intelligent alien civilization. Still, Occam’s Razor says it’s unlikely that the very first object we ever see from interstellar space just happens to be a spaceship–a slow, inert, disguised spaceship–built by aliens. Aliens whom we have no evidence actually exist, incidentally.

Fortunately, we can do better than that. Andy Rivkin at Johns Hopkin’s Applied Physics Lab reminded me of a great test case. In 2002, astronomers noticed a small, fast-spinning object in an unusual Earthlike orbit. Spectroscopic observations revealed rough matches with aluminum and paint containing titanium oxide. The object was quickly identified as an Saturn V rocket upper stage, probably from Apollo 12.

A Saturn V third stage like the one discovered adrift in 2002. If something like this arrives from deep space, we will know. (Credit: NASA)

A Saturn V third stage like the one discovered adrift in 2002. If something like this arrives from deep space, we will know. (Credit: NASA)

In other words, artificial objects tend to look artificial. Granted, we knew what to look for when trying to identify an Earth rocket. Granted further, an alien artifact that has been floating through space for millions of years could be heavily altered by radiation and micrometeorites. But still–there’s nothing about `Oumuamua that looks fake. Just weird.

Which brings me to the final, most exciting point. `Oumuamua is not the end of the story; it is just the beginning. The planet-formation models suggest that one to ten interstellar objects pass through our solar system every year! We haven’t seen them before because they tend to be fast and faint. New tools like the Pan-STARRS survey finally caught one that happened to pass especially close to the sun.

Future surveys will be more sensitive, and now scientists will be looking more actively for other visitors to see if they are like `Oumuamua or if they are something else entirely. The Large Synoptic Survey Telescope will be revolutionary in that regard. Right now, `Oumuamua is in a class of one. We don’t now if it is an outlier or if it is somehow typical of the objects that zoom past us from other star systems. Soon, though, we will have a whole catalogue of such objects to study and puzzle over.

We will learn about their compositions, their shapes, their trajectories through the galaxy. Already we can see from its motion that `Oumuamua does not seem to be associated with any of the nearby stars. We will see how many interstellar objects are rocky asteroids and how many are icy comets. We will begin to collect direct evidence of what happened to planets in other star systems, so we can compare their history to our own.

And maybe, just maybe–I know, I’m inching back onto the crazy train here–but if any of those objects show any sign of artificial origin, there’s an excellent chance we’ll know that, too.

Follow me on Twitter for the latest science news: @coreyspowell

  • Uncle Al

    10:1 axis ratio and a mean radius of 102±4 m, DOI:10.1038/nature25020

    The is no way to spontaneously random aggregate that shape. There is no way to collisionally spall it off re the Giant’s Causeway. It is not biological re stromatolites. Unless its cross section is round it will have three different principle moments of inertia and tumble rather than rotate (about its short axis). Three origins are allowed by observation:

    …1) Anisotropic progressive radial aggregation re stalactites. It’s more than a km long.
    …2) Extrusion re frost flowers. It’s more than a km long.
    …3) Fabrication. It’s a derelict starship.

    It was exquisitely aimed at our star. We are idiots. Bloody plot its reciprocal orbit to trace its origin, then SETI. Bloody don’t send a radio signal there.

    • Uncle Al

      Occam’s Razor says it’s unlikely that the very first object we ever see from interstellar space just happens to be a spaceship

      Occam’s Razor demands the very first object we ever see from interstellar space just happens to be a spaceship. If you wish to hit target, aim at it.

      • Seariously

        Well, if Occam’s says it, then it has become ontological truth. Nothing more to be added here folks. You can all go home.

      • DeNorte

        Nah, What Bill really says is “it’s a potato with one bright end and one dark end”. 😉

    • Flightcrew

      BIG TIME don’t send a radio signal there!

    • Corey S Powell

      Current estimate is that `Oumuamua is 400 meters long, not over a km.

      Some reasons to be dubious about an ET origin:

      Standard models of planetary formation imply that each star system sheds trillions of objects into interstellar space, so finding one passing through our solar system is not a surprise. There should be up to 10 interstellar objects passing by us each year, and astronomers have been looking for them for decades. Selection bias means that the first discovery is overwhelmingly likely to be an object passing close to the sun.

      Aspect ratio of `Oumuamua *is* a surprise, but the shape is not well constrained because we don’t know its orientation or possible albedo variations on its surface. Note that elongated objects (though less extreme) are common in our solar system, not formed via any of the mechanisms you have listed.

      Finally, note that at its interstellar velocity of 26 km/sec, `Oumuamua will take 50,000 years to reach the distance to the next star system. That would be a slow path to colonization!

      • Uncle Al

        Current estimate is that `Oumuamua is 400 meters long, not over a km” Post a DOI, arXiv, URL, or literature reference.

        OK, it is 400 meters long with a 20 meter radius. My analysis remains sound. Navigation is by AI. Its payload might be the equivalent of terraforming, removing competition, planting the far end of a wormhole, or something charitable.

        Youtube v=dk01eeKMD_I Yeah, charitable.

        • glucose

          It’s not the difficulty of creating such an object by natural means. It’s the fact that no such object would survive 300,000 years intact. Any violent creation process would spall off multiple objects that would smash it into the more typical 3:1 aspect – which is all we have ever seen in asteroids in our own system. It’s not the creation that is abnormal, it’s that such an object still exists after 300k to a few million years.

        • Corey S Powell

          Like I said, there are a million ways to make up an alien-artifact story that is impossible to falsify. It could be an alien ship designed to look just like an asteroid. It could move at warp speed, but only when nobody is looking. It might have a mysterious mission that required it to take a seemingly random path through the solar system.

          The problem is, such stories give you nothing to work with. There is no way to investigate them and no way to disprove them. The challenge is coming up with testable hypotheses–and, at the same time, gathering as much information as possible about `Oumuamua (and likely future interstellar objects) to find out their true properties.

          If they are artificial, that would be hugely exciting. It would probably rank as the greatest discovery in history. We need extraordinary evidence to convincingly make such a claim.

          • Matthew Slyfield

            “It could be an alien ship designed to look just like an asteroid.”

            I would think a more likely scenario would not be disguise, but the use of a hollowed out shell of a natural asteroid as a hull to reduce resource requirements to build the thing.

            Not that I believe that It’s likely to be artificial.

          • tjrich

            But it doesn’t look like an asteroid, it kinda looks like a spaceship. LOL

          • Corey S Powell

            Ha! Yes, but spectroscopically and dynamically it looks like an inert rock, not like an artificial object with any kind of energy source.

          • tjrich

            That aside – and just going with its look!! Woooaaa! LOL

          • Numa Pinto

            because it’s not an actual photo. they used radar. some artist made the picture

          • tjrich

            YA Think??? LOL

          • okiejoe

            And then, it could be an asteroid designed to look like a spaceship, an interstellar prank.

          • OWilson

            See Yeti and Sasquatch speculations in another blog! :)

            “Could be” – anything!

        • glucose

          I think this is the current list of oddities – are there more?:

          1) Coming in from a direction perpendicular to the planetery plane of our system, and instead of smacking into the sun, or having a low=level interaction where it continues on only slightly deviated – it instead shoots off in a direction that takes it right over the earths orbit, pretty much at the same time as earth is going through that part of its orbit. The object was about 15 million miles from earth at minimum,
          and got within 8 millon miles of Earths orbit at that same point in time.

          Great observation point without having any chance of accidentally “interacting” with the object you’re observing. Wouldn’t want to get too close in case we’ve built infrastructure within radius. They get close to Earth, and only afterwards shoot up between the earth and Mars to get away from the planetary plane that has lots of’ “stuff” in it to avoid.

          It’s a perfect approach for laying eyes on the earth, while minimizing exposure to impact damage.

          That’s highly unlikely for any one, singular object. If you’re talking about 100 comets in a year, where one comet comes kind of close to earth, that’s one thing. This is another.

          2) The aspect ratio. NO object has been directly imaged or observed in our solar system with anything more than a 3:1 dimensional ratio. This object is 10:1 at a size(400-800m length) where it should be gravitationally attracting other objects into it.

          We know of no mechanism for creating such an object, and any such object should have been smashed into smaller, rounder bits in the 300,000 years it traveled through two star systems. It’s an object with a shape that has 0.0% chance of existing(to several decimal filled with zeroes)..

          3) It’s rocky/metallic.

          4) The current hypotheses about the nature of interstellar objects like this state that the probability would be similar to Oort Cloud objects. IE, the probability would be between 2000:1 all the way up to 10,000:1 that the object should be an icy object like a comet – rather than rocky/metallic like an asteroid.

          They hit the jackpot this way as well. They are discussing changing the hypothesis/probabilities – but what if their original estimates are correct?

    • FrankK

      I disagree. Send it

    • Joz Jonlin

      It’s approximately .4 km long. Just over 1300 feet long.

    • Numa Pinto
  • Ld_Elon_Postman_RoyalMale

    Occam’s razor states a high probability, cuz humans can do it, FIRST, too.
    But its likely a high possibility due to determined factor of ZERO evidence of other life, but evidence of human/intellectual ability.

    Besides one will state again, looks like a targeted trajectory hit aimed at earth using mercury as trigger, just missed. that’s why its being classed as a message from ming the merciless.

    • Francisco Luis Gonzalez

      ET is a false lead intellectual construct like focusing on race rather than specie. Someone here said, if you want to see ET look in the mirror. So true. The universe is primed for life and sentiency is its biological conclusion (after that it is AI). So much to do about the obvious!

  • Pascal Bourguignon

    As long as it’s balistic, there’s no reason to believe it’s artificial. On the other hand, it would be very cool to send and land a sonde on it, so that it may brought back along outside of the solar system in that direction. I wonder if there’s still time to make a mission?

    • Corey S Powell

      Sending a probe to `Oumuamua is just on the edge of possibility, but it would be an extremely difficult and costly mission. More information here:

      • informatimago

        Thanks for the link. Indeed, Since it passed perihelion in September, it seems too late to catch it economically. It’s really too bad it hasn’t been detected much earlier, since it actually passed by in front of Earth quite close; it wouldn’t have been too expensive to rendez-vous there (only we’d have to design our sonde to withstand an inelastic collision at more than 30 km/s perhaps something made of bubblegum?)

  • George Levanduski

    “Aliens whom we have no evidence actually exist, incidentally.” Do we have to see someone shaking hands with them at a press conference? The authorities stifle widespread publicity of what is known about ETs. The Nazis had help, and now we know they were busy in South America and Antarctica after the defeat of Germany. Von Braun said he could put us on the moon and beyond in a year or two if they gave him the go ahead.

    Our wealth-obsessed rulers don’t even want us to know too much about human origins. There are pure-blood Cherokee Indians with DNA that matches that of a Semitic tribe who lived in the heart of Israel when Jesus Christ was born.

    The apparent weight-counteracting effects demonstrated with high-voltage electrically charged devices does not depend on electrostatic repulsion. High-energy electromagnetics is actually electrogravitic. Gravity waves! Antigravity propulsion. The force is in the opposite direction of electrical polarity. Now we know what Tesla was up to with his car driven by a box with an antenna! Think in terms of Kecksburg PA (de Glocke: the Bell) and the weird test structure for it in France for which the Germans allocated more defense resources than at the front until they could get it out of there!

    • Sven_Golly

      “There are pure-blood Cherokee Indians with DNA that matches that of a Semitic tribe who lived in the heart of Israel when Jesus Christ was born.”

      No there aren’t. Dial back on the mescaline George.

      • Uncle Al

        Mormons are more than decent people. Their narrative is no less believable than those of the the competition, which is to say “not much” in every case.

      • George Levanduski

        No mescaline or other drug is involved. I have conveyed what I read in a serious book. If you think the author has offered misleading or unfounded information, or you have contrary information, please explain.

      • J***h2

        Kennewick man shot that theory to hell.

    • J***h2

      The proof of Aliens is looking back at you in the mirror!

  • Anil Prasantha

    This is a computer generated picture. What we actually know is the proportion. 1 to 10 ratio.
    According to one article, there are no asteroid with this ratio in our solar system.
    What is the mechanism of forming an asteroid with this proportion ratios?
    What is the chance of random interstellar asteroid, very accurately travel this close to the sun and inner planets in Goldilock region?
    We have already discovered hundreds of exoplanets with the possibility of billions. Do we think that there are no other advanced civilisation among these planets?
    Check the position of the planets when this object passed through the solar system. Close fly by sun and closest approach to a planet is Planet Earth, extremely unusual very elongated shape. If this is a natural object, it is extremely rare co incident.
    This is a flyby mission to planet earth, until proven otherwise.
    No wonder we get the attention, of any other civilisation, because we were emitting lot of radiation, radio waves, nuclear explosions etc.
    For a probe of an adequately advanced civilisation, flyby distance of 1/4 AU, like this one is adequate to gather reasonable amount of information .
    Heat signature is rubbish. No advance civilisation will waist energy in heat.
    Transmission, ok it will transmit after passing other planets.
    How do we know wether there is a course correction about 100 light years away, when it sensed our radio transmission?
    In astronomical distances, this is a Bull’s eye to sun and planet earth.

    • Uncle Al

      Heat signature is rubbish. No advance civilisation will waist energy in heat” Why do nuclear reactors have cooling towers for their steam generators? The Second Law of Thermodynamics: “You can only break even on a very cold day.” Space is 2.725° kelvin. It will have a heat signature with space as its heat sink.

      • glucose

        Heat is for civilizations that have insufficient superconductors and
        insist on using chemical or nuclear heat-transfer mechanisms where there
        -is- waste heat to dispose of.

        Something like a ZPE or some other direct quantum foam energy
        harvesting mechanism may not have to worry about disposing of waste
        heat because they generate zero thermal energy to begin with.

        Who knows what the heck is possible?

        Trying to say “they” can’t have a zero-waste-heat energy system is like people in the 1800’s trying to tell us that we can’t have computation without using steam engines.

      • Anil Prasantha

        Yes if we think we are verybadvance civilisation. Less than 20000 years of civilisation. Imagine the technology of a 200000 year old civilisation.

    • glucose

      The other strange thing is that its orbit around the sun just happened to fling it over in our direction, or at least from my
      watching the simulation.

      It passed by earths orbit right around the time that earth was there in its orbit. Granted, the outward path from the sun was not on the same plane as the inner planets.

      What’s the probability of some random space junk shooting in and around the sun – at random – and just happening to pass by the earths orbit at the same time as the earth? How often do comets shoot in around the sun, and then happen to trundle past the earth, either on the inner or outer side of the orbit? And that is with comets that are typically close to the same plane that the planets orbit in. This object was shooting in from a more-or-less perpendicluar, non-planar hyperbolic orbit, and just -happened- to exit it’s interaction with the sun in a direction that – if it was one of our own spacecraft, you’d need to calculate and arrange in advance?

      The number of oddities and extremely unlikely happenstances with this thing is just too much.

    • Corey S Powell

      A few things to keep in mind.

      First, we do not know the exact aspect ratio. Meech et al find a 10:1 ratio. A competing team found something more like 4:1. And since we have no idea if there are dark and light patches on the surface, it’s impossible to know how much of what we are seeing is shape and how much is coloration.

      Second, there is a huge selection effect at work here. In the ~20 years we’ve been conducting detailed surveys, there have probably been dozens or hundreds of interstellar objects passing through the solar system. It is inevitable that the first one detected would pass relatively close to the sun & Earth, because that makes it especially easy to find. What are the odds that out of a couple hundred interstellar objects, one of them happens to pass somewhat close to Earth? Pretty good, I’d say.

      Finally, there’s the issue of heat. I have no idea if alien tech would give off a heat signature. All I know is that a peculiar heat signature would be a concrete sign that something unnatural is going on, so it’s an obvious thing to look for.

      • glucose

        Thanks for the comment about the selection effect. I’d forgottten about that.
        If it’s the only one we would be likely to detect – because it came close enough to trigger things – ….

  • Monday Morning Warrior

    Funny how MAN thinks he has all the answers…just because it doesn’t fit our perception of a “space traveler”…Foo foo it immediately…how small man really is…we are but an insignificant piece of rock among Quadrillions…but oh Man knows it’s not from another planet…pfft…you’re not as smart as you think you are!

    • disqusaurus_rex

      It has nothing to do with any sort of “all answers”, and a lot more to do with the fact that out there in space, rocks vastly outnumber spaceships – so the odds are very, very long that this isn’t a spaceship and is in fact just a rock. (Particularly given that the colour of the object is exactly what you’d expect from a rock long exposed to cosmic rays, which is exactly what an interstellar rock would be.)

      • Monday Morning Warrior

        OK..Mr. Scientist…you have ALL the answers…smh…Mankind’s overwhelming LOVE for his LIMITED KNOWLEDGE of how things work is pathetic…IT’S ALL THEORY!!! There is no PROOF that our way of looking at things IS the RIGHT WAY…thats how self-centered Scientists think they are…if it doesn’t serve their INTERESTS oh then it can’t be right (et. la TESLA s superior AC CURRENT)because blah, blah, blah physics blah, blah, blah…that’s why EVERYDAY we learn something about the Stars…If you think you or Mankind knows everything about SPACE…you sir are a MORON

    • Corey S Powell

      I think you have it upside down. Scientists start from the position that they *don’t* have the answers. They start with the questions, make observations, and go from there. They are looking for evidence about what this object is, and learning as they go. If you start with a belief that `Oumuamua is an artificial creation, before you have any evidence to support such belief–well, *that* would be assuming you have all the answers.

      • Monday Morning Warrior

        No …they ASSUME man is superior…BS..We can’t even get along on this blue marble…Man’s idea of his GODLINESS is pure hokum…we are the parasites

        • TZ.Solo

          “I’m sure if there is something out there, looking down on us from somewhere else in the universe, they’re wise enough to stay away from us.”— Gil Grissom

    • Corey S Powell

      Note: Responses that contain personal insults or hostile language will be deleted.

      • Monday Morning Warrior

        Who the hell are you???

      • Corey S Powell

        Second warning. Please keep it polite in the comments section. Thanks.

  • TLongmire

    Nobody is questioning wether their interpretation of dimming is correct🤔

  • Sven_Golly

    I have been waiting for an article to mention “Rendezvous with Rama”, thanks Corey.

    • David Guaraglia

      I am surprised that so many articles have missed the reference. You’d expect that to be the first thing to come to mind!

    • DonChalant

      I was seeing the space vampire needle ship from “Lifeforce” myself.

    • Bruce M Carleton Jr

      Just wait for two more of them.

  • Electronic Fish Lure

    Is that a giant space joint sent by aliens to tell earth to chill out… :-)

    • Lacombe57 .

      Hey… Further Out than ever dude.

  • Birdie opp.

    It’s Gumto!!!

  • 10basetom

    It’s obviously a Zentradi fly-by ;).

  • Ashwin Campbell

    I think it looks like a giant cat turd, probably from some long extinct species of space cat. Thunder from down-under Cats, Ho!

  • Tryfon Farmakakis

    I am surprised that in almost every article I’ve read on this subject the possibility of such an object to collide with Earth is not even mentioned, despite the fact that we know today that it is a a very high probability, that it has happened again in the very near past with devastating consequences and on top of that we have no system in place for discovering and tracking such objects early and haven’t even tried yet any of the proposed methods for deflecting one. Of course the technology to achieve this is already here (and has been here for quite a few years actually) but we, as a humanity, prefer to invest trillions in weapons systems and to develop and deploy the same systems multiple times because nobody trusts each other (for example: GPS, Galileo, GLONASS, BeiDou)
    Almost all necessary information can be found here:

    • Ralph McCulley

      Oh my god I was thinking the same thing!!!!! We are so worried what we are going to do to each other as the human race, but what if one of those behemoths are on a collision course to our planet?!? Instead of trying to figure out how to destroy an astroid they’re too worried about destroying each other

    • Glen Cockrell

      Or just pass close enough to screw up our solar systems orbit paterns.

    • Corey S Powell

      I completely agree that we should be spending more to catalogue potentially hazardous comets and asteroids, develop early-warning systems for small objects, and create technology to prevent major impacts. That said, the overwhelming majority of the risk comes from objects in our own solar system, not from the much rarer ones arriving from interstellar space.

      One piece of good news: the Pan-STARRS network that found `Oumuamua was established to study the broad population of hazardous objects, and this discovery is an example of how well the effort is proceeding.

    • Synoptic 1

      you have to keep feeding homeless, poor people, primitives, non workers, most Humanity s skills are menial, and computers used for entertainment or these comments, weapons are an inbuilt Human need, tech available is not enough, a good ol 70s AI ES could have dispatched analysis orders and not wait for slow researchers to catch up but we do not have it, keeping ambiguity on this is a way to fend attacks from several groups in case… I would have missiled it then collected whatever data was further possible, not just we were waiting let it go leave it uncertain nothing (else) to do, but these comments show Reason is quite partial and the lesson is it is not one of Our priorities.

    • George Stranahan

      What if it is the anunaki planet

  • Hard Little Machine

    Weirdest looking Stargate.

  • OWilson

    Your problem can be reduced by Occam’s Razor, thusly!

    1. “We didn’t get much of a chance to study it, unfortunately!”.

    2. “Its brightness changes drastically, indicating a highly elongated shape”

    3. “Artist’s Impression”.

    4 “Could this be a dead, abandoned spaceship?”

  • Maurice M Taylor

    It’s a giant toothpick..those aliens are really big..

  • West

    What would be the kinetic impact of an object 400m x 40m if it hit Earth… and, where would it have hit us?

    • Tryfon Farmakakis
    • MacCaskill

      Wa-a-a-ay too many unspecified variables in your question for any definitive answers. Stony or nickle-iron? A metallic one this size, at the speed Oumuamua was moving as it crossed Earth’s orbit, impact energy could have been in the range of 4 megatons. Where would it hit “If it hit Earth”? It wasn’t on a course to hit Earth so if you arbitrarily changed that, where it hit would depend on exactly how you changed its trajectory. It’s a meaningless question as asked. That’s like: “If you shot me where should I put the Band-Aid?”

  • Lori Schaller

    I believe it is an asteroid, just as we have many different looking rocks on this planet, I think that it was bumped in ways that most the others are not, … and that is why it is shaped different.

  • Pierre Clouthier

    I have a great idea for a Science Fiction story: astronomers observing the asteroid through telescopes, discover artificial markings on it. Everybody scrambles to record the glyphs. We only have a few days to copy them, then the asteroid is gone. Imagine the impact on human civilization: we had a brief glimpse of other life, and we’ll never know what it means.

    • Tryfon Farmakakis

      I guess you ‘ve never read classic science fiction, because if you had you wouldn’t find this to be a “great idea”.

      • nik

        in what way is this a bad idea regardless of his potential lack of having read science fiction?

        • glucose

          Not a “bad” idea, just a common one. Every
          10th SF novel uses a theme along the same line.

          • nik

            Gotcha. Makes sense

          • glucose

            Yeah – you probably wouldn’t make any money writing stories like this.
            OK, maybe you would. 😀

    • Uncle Al

      It’s a food truck on a shopping trip;

  • Lori Schaller

    I want it to be a ship, … but, this just is not it, … if it were,… why would they just be hanging out there? … it is an asteroid !

  • FrankK

    Imagine if this was a Rama craft… the timeline would b over 100 yrs early… please show signs of being more than a rock

    • glucose

      It’s given us sufficient sign, if we were actually paying attention.

      1) Coming in from a direction perpendicular to the planetery plane of our system,
      and instead of smacking into the sun, or having a low-level interaction where it
      continues on only slightly deviated – it instead shoots off in a direction that takes it
      right over the earths orbit, pretty much at the same time as earth is going through
      that part of its orbit. The object was about 15 million miles from earth at minimum,
      and got within 8 millon miles of Earths orbit at that same point in time. Great
      observation point without having any chance of accidentally “interacting” with
      the object you’re observing.

      That’s highly unlikely for any one, singular object.

      2) The aspect ratio. NO object has been directly imaged or observed in our solar
      system with anything more than a 3:1 dimensional ratio. This object is 10:1.

      We know of no mechanism for creating such an object, and any such object
      should have been smashed into smaller, rounder bits in the 300,000 years it
      traveled through two star systems. It’s an object with a shape that has
      0.0% chance of existing(to several decimal points filled with zeroes)..

      3) It’s rocky/metallic.

      4) The current hypotheses about the nature of interstellar objects like this state
      that the probability would be similar to Oort Cloud objects. IE, the probability
      would be between 2000:1 all the way up to 10,000:1 that the object should be
      an icy object like a comet – rather than rocky/metallic like an asteroid.
      They hit the jackpot this way as well. They are discussing changing the
      hypothesis/probabilities – but what if their original estimates are correct?

  • George

    That exactly like one parked in the far side of the Moon, in a crater, just like it’s showing in Apollo missions photos.

  • Joz Jonlin

    There have been many ideas about modifying asteroids to create spaceships for local habitation or even interstellar travel. It’s technically possible to create this. There’s no way to prove it’s not a dead spaceship in the form of an asteroid. Still, just no, no, and no. It’s just a rock passing through.

  • Sachi Mohanty

    Alien talk is so silly that I won’t bother entertaining them.

    But an object that passes through the Solar System and basically uses gravity (Sun’s, in this case) for that slingshot effect — like we humans have sometimes done with our own spaceships like the Voyagers (did New Horizons and Cassini Saturn use gravity assist? I forgot.) and like we had to use with Apollo 13 — seems like what an intelligent species might choose to do.

    Something we humans might do in the future. Send a spacecraft towards Alpha Centauri with an orbit so precise that it slingshots and returns to the Solar System after thousands of years.

    We would do that in the future, right? Remember that everything is moving and over tens of thousands or hundreds of thousands of years, the Sun and the target star systems would have moved significant distances.

    But calculating trajectories is something we already do to send spacecrafts to the planets. The orbital mechanics guys would love to take their skills to the realm of the stars.

    I guess science fiction writers must have written along these lines.

    I am not saying this ‘visitor’ is a messenger or spacecraft from an alien civilization.

    It would be quite embarrassing — or, at least, it should be — if aliens did arrive and realized we are ‘armed to the teeth’ (is that the right phrase?) to kill all (or almost all?) life on Earth using nuclear weapons.

    They might ask us: “Now, why would you want to destroy yourselves? It took billions of years for life to come to such a level of technological sophistication and to now destroy all (or most) of that … and over WHAT … that sounds pretty odd, silly, dumb, and much worse.”

    [Note: what would be a measure of time with some universal applicability? A ‘year’ is clearly a very anthropomorphic yardstick to measure time.

    Again, sci-fi writers would have probably grappled with this question.]

    So, before we get asked to explain why we are like this, we might like to do something with those nuclear weapons … at least reduce the chances of total annihilation may be.

    Bring down the numbers of those ‘toys’ to the tens, from the thousands.

    What do you say, Mr Putin? What do you say, Russians?

    [I am sure (a majority of) Americans would agree, even if some may not.]

    • Corey S Powell

      There are interesting ideas for using gravitational slingshots to accelerate interstellar spacecraft, or for slowing them down so they can go into orbit around their target stars. See:

  • BydandMoor

    “It looks very much like Commodore Decker’s planet killer…”

  • Zeek Wolfe

    Rendezvous with Rama is the best science fiction book I’ve read.

  • MacCaskill

    Have continuing observations refined our picture of Oumuamua’s measurements? I’m still reading write-ups stating a length of about 12 or 1300 feet with a 10:1 aspect ratio. Is this just a matter of later articles merely copying information from the first announcements or are the latest observations reinforcing the early ones?
    Obviously, I’m not the first who saw those numbers and the phrase thought: “spacecraft!” Do I actually believe that? No, not really, but the hopeless romantic in me would love to. For a natural object, it IS damned odd. I keep trying to imagine physical processes that would result in something of that size and shape. The ONLY thing that has come to mind would be a cooling protoplanet forming structures like the Devil’s Causeway basalt columns (which would seem to call for a rather large body), then being relatively gently broken up in a collision with another planetoid that scattered intact columns … anyone else finding that one hard to swallow?
    We have yet to see any native asteroids remotely resembling spindle or spire shapes. You don’t haphazardly bash rocks together and create quarter mile long spires of rock or nickle/iron.
    IF it was an artifact, an honest-to-God alien spacecraft, a fly-by does not mean it was even intentionally launched toward our solar system. There are a near infinite number of possibilities…
    About 3.76 million years ago a ship on a voyage of exploration or trade or for reasons imaginable to none but the totally unhuman minds that created and crewed it, had the misfortune to be caught in a gamma ray burst, frying the engines and control systems and killing the passengers and crew instantly. The builder’s civilization endured for almost sixteen hundred years before stagnation and ultimate collapse. The ship, only one of scores of craft to vanish without trace in over one and a half millennia, continues to drift on.
    Six billion years ago, when our solar system was but cold wisps of tenuous gasses and interstellar dust grains, a flourishing young technological civilization launched an A.I. controlled, autonomous, interstellar exploration ship to reconnoiter several nearby solar systems. Returning home ninety years later to report its discoveries, it found former population centers to be glassy, radioactive craters and no indications at all of life more advanced than algae. Knowing no other purpose, it set out on its own in search of another intelligence. But all things die. Eventually backup and maintenance systems malfunctioned and ultimately the energies that propelled and directed it failed. Slowly high-energy cosmic rays scored and scorched its once-gleaming hull dark and rough, burned away its sensors and bereft of means to apprehend the universe, it drifted on through eddying currents of stars till it was no longer possible to know which its home sun had been.. So it was that, voices stilled, deaf, blind, and quite insane, the brown, burnt, eroded husk of what, unimaginable eons ago, had been a proud and powerful expression of curiosity and power; now the sole existing fragment of evidence a magnificent race had ever lived, plunged through a minor yellow dwarf star system, where by fluke, it was noticed by a few members of a young race in the early stages of technology inhabiting the third planet of the star. For a pitifully few hours they wondered at this anomalous object from the stars as it passed by and with unappreciated irony, named it “Oamuamua”, — “First Messenger From Afar.”

  • Joshua Joshua Joshua

    I have another approach which I hope some of you will appreciate.. Perhaps the object is a bit of both, artificial and natural. If it were artificial then most of us would see that as a sign of alien intelligence. But who is to say what life could be lurking .. in the natural. Consider this- a rock can be a lot lot older than we could ever be. Interstellar visitors could be stages towards life . We have metaphoric rock but that rock out there could give that a whole new meaning.

  • John C

    No, it’s not aliens.

    But how odd that on Earth life is everywhere, in such profusion, from the stratosphere to deep ocean trenches, Antarctica, sulfur springs and hot cracks in the mantle.

    Yet not a single sign yet of life anywhere else in the cosmos.

    • ikariwarriorsteam

      According to the new analysis, a whopping 22% of sunlike stars have planets more or less the size of Earth in their habitable zones. That adds up to about 20 billion Earths in our galaxy alone, says lead author Erik Petigura, of the University of California, Berkeley.Nov 4, 2013

  • dsands47

    Oumuamua koniki hawa !!

    • dsands47

      Translation: “The strange asteroid is out-of-here.”

  • Erik Bosma


    Well, it COULD be a Berserker. What irks me is All my life I’ve been told that if we could reach relativistic velocities we would never have to worry about hitting a star or black hole or any other such object because they are all so far apart and spread out that it would be against very high odds to hit anything. Then here comes an interstellar “asteroid” and it does a near perfect loop-de-loo around the sun and then skims by the only planet with ‘intelligent’ life on it. Hmmm….. Maybe we’re not intelligent enough for their liking. Maybe we’re not as smart as we thought we were when an alien ship in a hollowed out asteroid takes a pass at us like it did. But they did give us a good idea… Instead of wasting all that time and metal building a huge ship superstructure, hollowing out an asteroid would be a lot cheaper and less time consuming. Too bad we couldn’t visit it.

  • batty bill

    o.k. just to say I am in the e.t. camp here,my best theory on this object is that is a throwaway booster,any kind of craft approaching from deep space would have to be going really fast,and would need to slow down to solar system speeds,if that is the case then there just may be some sort of craft following on the same course but much slower,could be months or even years away,nice to let your imagination run riot now and then,but it is an interesting theory that fits the facts.

  • OWilson

    They never stopped to say hello?

    Didn’t pick that Texas couple for experiments?

    Didn’t even ask to be taken to our Leader?

    Who need’s ’em?

    • James Thompson

      Are we sure we would want to take them to our leader?

    • Grizzly59

      With the current “leadership” of our nation, who TF would even think about stopping here. They did a sonogram and the only intelligent life forms were being hunted to extinction by a pack of gibbering naked apes. The conversation on board went like this: Should we drop by for a closer look at that odd satellite of this fueling station? ” No, Given our information garnered, there is no intelligent life on that satellite. Proceed on course to our original destination. We still have a signal from them!”

      • OWilson

        Trekkies, Star Wars, and ET fans always assume aliens are these aging liberals, out to save humanity!

        (As usual they failed, because we are still here!) :)

        I have an opposing Rod Serling take!

        They are right wing Trump lovers, who with their universal intelligence, fixed the last election, and just flew by to make sure their plan worked! :)

        We need sensitivity training in schools so that ALL alien theories are equally represented!

  • CO Jones

    Have we still got that pair of humpback whales named George and Gracie handy, just in case?

  • bwana

    Oumuamua just stopped by our Sun for a “drink” then it was on its way to other more interesting places in the Universe…

  • Grizzly59

    Perhaps it is an unoccupied intergalactic probe! Oh, the intergalactic laxitive will get you from here to there, as surely and securely, without a worry or care! If shitting is a problem when you’re out there in the stars… Oh the inter galactic laxitave will get you from here to mars!

  • Grizzly59


  • pfon71361

    Groucho Marx might have remarked: “Last night I shot an asteroid in my pajamas. What that asteroid was doing in my pajamas I’ll never know.”

  • RickDick

    I am leaning toward the ET theory, based on some of the excellent rationales provided in this thread so far. Trajectory and shape sold me. But the clincher was the fact that it came from the direction of Vega system. Vega looks very much like our own solar system, and may have habitable planets. IF ET is in our region, Vega is a good place for it to be. Also, sending a probe camouflaged to look like an asteroid is not a bad idea, if you are not wanting to arouse suspicion or you don’t want someone to come looking for you either. After all, they may not be hostile, but ET doesn’t know we might be.

  • RickDick

    Three things about this mysterious cosmic visitor that lead me to believe it may be ET:

    (1) Shape…We have never seen a cigar-shaped, rotating asteroid before. Rotation would enable a form of artificial gravity inside. Looking like an asteroid, or being made from an asteroid, would be good camouflage to not arouse attention either.
    (2) Trajectory…Not like any other asteroid or comet. Passes close to sun but far enough away from earth to prevent close examination than deflects back into space at a strange angle.
    (3) It’s trajectory indicates it came from the Vegan star system, which is close by (25 million years) and is similar to our own star system with two asteroid belts and may even have rocky and other planets.

    According to astronomers, Vega looks like a bigger twin of our own solar system, although Vega is 600 million years younger than our sun. Doesn’t mean intelligent life could not have evolved faster there than here either. Also, It raises the interesting possibility that the object is a probe observing all star systems like earth and Vega, and comes from somewhere else, collecting info on the presence of life and particularly intelligent. ET research probe or scout for future ET invasion? Is the cup half full or half empty? Take your pick.

  • RickDick

    I would also like to add that its trajectory around the sun uses the classic “slingshot effect” we employ on our long distance planetary probes.

  • Randall Sharp

    Hmmm missed our chance to check for that mineral that made interstellar flight possible according to that area 51 engineer

  • DeNorte

    With all respect to Dr. Meech, the assumption about shape seems somewhat speculative. The magnitude variations could also be associated with variation in surface albedo instead of shape, right?

  • John C
  • okaydokay

    well they say that interstellar objects make up 5% of the mass of the galaxy….. still theres a lot of space also F. Hoyle said in around 1999 that the absorption spectra of star dust looks a lot like that of bacteria….so…?

    • okaydokay

      we need to look at astrobiology and exobiology and pansperia considerations…

      • okaydokay

        It may afterall be some kind of space faring dino creature, capable of withstanding the vacuum and cold of space…. with a 20 inch thick skin of some sort, propelled by gravitational ping ponging.

  • Riz

    thats was a Sirius hollowed out asteroid spacecraft.

  • Robertarvid Johnson

    Visualise the various possible shapes that could be fabricated by a space aliebut first,,, the cultural age of that alien… We on Earth are cultural infants, Our eyes recognized space only 400 years ago with the invention of the telescope.


Out There

Notes from the far edge of space, astronomy, and physics.

About Corey S. Powell

Corey S. Powell is DISCOVER's Editor at Large and former Editor in Chief. Previously he has sat on the board of editors of Scientific American, taught science journalism at NYU, and been fired from NASA. Corey is the author of "20 Ways the World Could End," one of the first doomsday manuals, and "God in the Equation," an examination of the spiritual impulse in modern cosmology. He lives in Brooklyn, under nearly starless skies.


See More


Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

Collapse bottom bar