Did an alien vessel just pass by? The mystery of Oumuamua.

Fascinating piece today at Spaceweather:


It sounds like a tabloid headline, but in this case it could be real. Mainstream researchers from the Harvard Center for Astrophysics have made the case that interstellar asteroid ‘Oumuamua could in fact be an alien light sail. Their original research was posted Oct. 31st on the moderated preprint server arXiv.org.

The story of ‘Oumuamua begins in October 2017 when it was discovered by Robert Weryk using the Pan-STARRS telescope atop Hawaii’s Haleakal? volcano. Astronomers quickly realized that ‘Oumuamua was something special: The object was hurtling through the Solar System on an unbound “hyperbolic” orbit. It came from the stars. Dramatic changes in the object’s brightness suggested that it was tumbling and asymmetric–thin and wide like a cigar or perhaps a pancake.

Above: This artist’s concept shows how ‘Oumuamua is usually depicted: as a cigar-shaped asteroid.

On its way out of the Solar System, something unexpected happened. ‘Oumuamua accelerated as if jets of gas were pushing it forward. Astronomers who initially thought ‘Oumuamua was an asteroid now turned their attention to the comet hypothesis. Comets naturally develop jets after close approaches to the sun, and such jets could explain ‘Oumuamua’s behavior.

Just one problem: “Despite its close Solar approach of only 0.25 AU (inside the orbit of Mercury), ‘Oumuamua shows no sign of any cometary activity, no cometary tail, nor gas emission/absorption lines,” point out the Harvard researchers Shmuel Baily and Abraham Loeb. Moreover, “if outgassing was responsible for the acceleration, then the associated torques would have driven a rapid evolution in ‘Oumuamua’s spin, incompatible with observations.”

So if it’s not an asteroid, and it’s not a comet, what could it be? Loeb, who is the chair of the astronomy department at Harvard University and also chairs the advisory board for the Breakthrough Starshot light sail project, realized that the acceleration profile was key. The non-gravitational acceleration of ‘Oumuamua scaled with distance from the sun (r) as r-2 — just like a light sail would behave.

Above: The comet hypothesis. Credit: NASA/JPL [more]

Modeling ‘Oumuamua as a thin object pushed by solar radiation pressure, Baily and Loeb found that it would fit the observations if it were a sheet of material 0.3 mm to 0.9 mm in thickness with a mass surface density of ~0.1 grams per square cm. “Although extremely thin, such an object would survive an interstellar travel over Galactic distances of  about 5 kiloparsecs, withstanding collisions with gas and dust-grains as well as stresses from rotation and tidal forces,” they wrote.

The researchers are now calling for more observations to look for ‘Oumuamua-like visitors to the Solar System. “A survey for lightsails as technosignatures in the Solar System is warranted, irrespective of whether ‘Oumuamua is one of them,” they conclude.

Although technical, Baily and Loeb’s paper is well written and unusually readable for nonspecialists. Check it out.

I checked out the paper, in PDF form.  “Unusually readable” means that there is some prose in it.  I followed part of it and a little of the math, but most of it was beyond me.   Still, this is really cool stuff.

And, if we prescind from this spinning, gas-jetting object zooming towards void and the brains of democrats that it resembles, this story has NOTHING to do with election day!

About Fr. John Zuhlsdorf

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  1. HvonBlumenthal says:


    If there is an alien pilot, and he lands on earth outside your vestry, what steps will you take for his salvation?

    Is the hypostatic union to be viewed as a literally “true God and true MAN or does Christ’s human nature stand for all intelligent life capable of sin and repentance?

  2. Pingback: Did an alien vessel just pass by? The mystery of Oumuamua. | Fr. Z’s Blog | Deaconjohn1987's Blog

  3. Michael says:

    Perhaps, if there were other intelligent life, it passed the test that Adam and Eve didn’t…

  4. majuscule says:

    Anyone who has read about UFO sightings knows they are often cigar shaped.

  5. Imrahil says:

    Dear HvonBlumenthal,

    while you ask an interesting question, let me adjust the expression a bit.

    Of course the hypostatic union was between God and – biological – Man, as it was one specific historical thing. That being said, I said “biological” man for a reason; it is not all all clear that “true man” means homo sapiens sapiens (or does it include at least the neanderthals)?

    The philosophers, in any case, wrote down as a sort of definition: “Man, that is: a mortal rational animal”; we might also say: “Man, that is: a biological life-form animated by a spiritual soul”. Whether this “man” has now has a somewhat ape-ish body or the body of (nodding to Mrs. Donnelly) an elephant or (nodding to Mr. Adams) a dolphin or a mouse, is not part of the definition.

    Which is why I would answer this interesting question that our Lord of course became a biological Man, and nothing else. This happened in history, and we know what He became, which is biological man and not any other life-form.
    However, when he effects by this the saving of fallen intelligent material creation from sin and the leading of her to everlasting bliss, then He can do that just as well with any other parts of fallen intelligent-material creation as for men, and even without a further miracle. Also, He can make even those who had not fallen in the first place part of his Mystical Body, as He has done with the good angels. (Coming to think of it: I wonder whether, as the angels don’t have material bodies, this required at its time a further miracle.)

    Note 1: Life-forms for whom water is toxic are exempt from the duty to get themselves baptized. Their path to salvation, absent a specific revelation, is baptism by desire alone; also, as they cannot validly receive any sacrament, they cannot take office in Church, just as little as women can become priests.

    Note 2: As the Bible says that priesthood will be extended to “all the nations”, which of course means biological men, but does not speak about those biologically not men, and for the same reason that women cannot become priests (because God became a male man), I don’t think an intelligent biological life-form can validly become a priest, even if water, wine, oil and bread are not toxic to it and it can be reasonably called male. However, I’m not 100% sure on this. Hence, priesthood, and I guess the deaconate, are – at least in the absence of a special revelation to the contrary – forever restricted to the male parts of the human race in its biological sense.

  6. Malta says:

    It is easy: not one of Christs disciples was a woman; if God wanted female priests, Im pretty sure he could have created a mechanism for it. Yet, Mary the Mother of God was a woman, who is above all of the Angelic realm.

  7. Bellarmino Vianney says:

    Well, the good news is that the above particular alien sail probably won’t contain any MS-13 gang members or “radicalized extremist Middle Easterners”…

    And, it is unlikely that these sailing aliens will take American jobs…

    And we can probably rest assure that the USCCB won’t be vouching for them, seeing that they can’t receive government funds for supporting the above particular sailing aliens….

    But yeah, as an analogy to election day today, indeed, the Democrats and their voters are much like the above (possibly) sailing aliens, heading towards the outer darkness, where there will be weeping and gnashing of teeth.

  8. Amerikaner says:

    I remember an interesting explain from a priest once on the possibility of alien life that would possess a soul:

    The Son of God became man and died for all in one point in time/space. Therefore it is not likely that rational alien life would exist that is fallen. Otherwise would Jesus would have to again die for them. That leaves the option that they are not fallen and still contain perfect minds. If so, they would know to avoid us.

  9. Amateur Scholastic says:


    “The philosophers, in any case, wrote down as a sort of definition: “Man, that is: a mortal rational animal”; we might also say: “Man, that is: a biological life-form animated by a spiritual soul”. Whether this “man” has now has a somewhat ape-ish body or the body of (nodding to Mrs. Donnelly) an elephant or (nodding to Mr. Adams) a dolphin or a mouse, is not part of the definition.”

    This is a controversial definition, to say the least. It seems to suggest a very un-Catholic separation between soul and body. The ‘rationality’ does not exist in and of itself, and does not ‘inhabit’ a body that is otherwise non-rational. Rather, the rationality is part and parcel of the body. Soul and body make one substance, one thing.

    Similarly, in traditional thought, a man and a rational animal are the same thing; the former is not a mere example of the latter.

    This isn’t the place for an extended discussion, but I suggest checking out Edward Feser’s work, or David Oderberg’s Real Essentialism for a detailed discussion of this very question.

  10. Kent Wendler says:

    It is quite a jump from an apparently tumbling interstellar object with an unexpected acceleration to an artificial object constructed by “e.t.’s”, when something like a giant mica flake seems to me much more likely.

    I have written elsewhere that if one carefully looks at Genesis then the existence of non-human extra-terrestrials contradicts Scriptural truth. (Adam and Eve, however, might have propagated off-earth if they possessed a sort of super-multilocation on a diminishing basis post-lapsarian.)

    Anyway, consider the Fermi paradox, the latest thinking on the Drake equation, the the continued failure of Project Seti.

  11. Father Bartoloma says:


  12. Fr. Reader says:

    The spirit of vc2?

  13. iamlucky13 says:

    @ Amerikaner and HvonBlumenthal

    C. S. Lewis explored this question as one of the elements of his Space Trilogy. You may find those books interesting to read, as long as you accept that scientifically they are fantasy, and theologically, they are speculative allegory.

    In one of the books, the main character encounters unfallen creatures, facing temptation to original sin. In another, he encounters creatures who I understood (although I’m not sure if that was Lewis’ intent) as having had a Fall separate from that of mankind, and who also saved by a separate Redemption.

    As for Oumuamua, while modelling it as a solar sail may provide a good fit for the published measurements of its acceleration, when that acceleration is only 1/20 millionth of the earth’s gravity as the paper notes, I’m not inclined to rule out the possibility of measurement error very easily. The idea of an extraterrestrial solar sail is very interesting, however.

  14. leftycbd says:

    Is this Rama? read _Rondezvous with Rama_ by Arthur C. Clarke

  15. DeGaulle says:

    Most scientists refuse to believe the evidence of their profession and of their senses, that life and inorganic nature, replete as they are with order and information, constitute plausible evidence for a transcendent creator, yet many will jump at a long shot like this. Can anyone explain this mindset.

  16. The Masked Chicken says:

    One of the best SciFi stories of first contact is A Case of Conscience, by James Blish. It stars a Jesuit priest.

    The Chicken

  17. JesuCorSanctissimum says:

    I forget where I heard this. It’s difficult to forget once heard. Someone posited that demons could pull one mighty ruse on humanity via an ‘alien interaction.’ Just sayin.’

  18. un-ionized says:

    Malta, Jesus had many female disciples, some of them named in scripture. He had no female apostles. Disciples are not to be confused with apostles. We have things like apostolic this or that as a result of this difference.

  19. FN says:

    Kent Wendler,

    “Adam and Eve, however, might have propagated off-earth if they possessed a sort of super-multilocation on a diminishing basis post-lapsarian.” What a fascinating concept. Please link to any writings of your own or others regarding this line of thought.

  20. Imrahil says:

    Dear Kent Wendler,

    I have written elsewhere that if one carefully looks at Genesis then the existence of non-human extra-terrestrials contradicts Scriptural truth.

    I don’t believe in intelligent extra-terrestrials myself and I am aware that the main-stream, when supposing their existence as a matter of course, acts on a false premise (viz. that since there is life on Earth, it is a “normal” state for a universe to contain life; if assumed, of course it follows that life will be present not only on Earth but also elsewhere; but for those who teach the existence of God the Creator the first one simply becomes a quite unnecessary hypothesis).

    Nevertheless, I’m rather surprised that you make such a statement. So, I’m rather interested in the answer to the question: What in Genesis did you imply that from?

    I have to admit I myself am rather convinced, at least at present, that the existence of intelligent extra-terrestrials is not contradicted in scripture (even though probably not the case in reality either).

  21. Kerry says:

    Masked Chicken. Wow! What a story!!
    It is here, go read it: https://archive.org/details/1953-09_IF

  22. Kent Wendler says:

    Dear FM and Imrahil:

    I did post a somewhat extensive series of linked and interrelated posts in the (now moribund but still there) successor to his old COL forum.

    The particular discussion is titled Are there alien intelligences?

  23. FN says:

    Thank you Kent. Interesting discussion on that page! Nothing about your multilocation hypothesis though. That’s what I’m really interested in. It seems to be of a piece with other ideas I’ve seen floated that Adam and Eve lived to around 900 and had various other gifts because (?) of their perfect human DNA which had not yet mutated, as it has since.

  24. What? no one here is going to mention panicking and running to stocked bunkers, and await devastation?
    bwahaha!! Its just a rock, not a comet, nothing to see here folks. THAT’s what they WANT you to think. Forget the Wrath of God and punishment for our sins, our last moments. Its just friendly aliens!

    tongue in cheek, yes.
    But I just finished re-reading the 1970’s Yves Dupont’s Catholic Prophecy [an old trad favorite] and there is plenty in there covering prophecies of a comet. Its a great read, published by TAN and also available free on the internet. The prophecies in there describe today’s chaos like its the current news. [antipope! foreign invasions! apostasy! natural upheavals! polluted clergy!] Sobering and comforting to know that what we are experiencing now is part of God’s plan, and hey, its gonna get WAY worse. Be grateful for what we enjoy now.

  25. Kent Wendler says:


    I apologize for missing that point. Briefly, it is my understanding that the prelapsarian Adam and Eve had, among other gifts, that of agility. Also, unimpeded intelligence – Adam did name the animals. One might easily suppose that they might look up at a star, and with their agility travel to it and its inhabitable planets.

    Postlapsarian, they might have retained some of this, but in an ever decreasing fashion; c.f., the decreasing life spans in the genealogy. Therefore one might speculate that while they still could, Adam and Eve might have traveled off-Earth and started other branches of humanity before returning. They might even had children in other places on Earth in addition to Cain, Abel, … (This would eliminate any need to resort to polygenism, or God selecting just one pair of “proto-humans” to become “images of God” while leaving the rest as “spiritual beasts”.)

  26. FN says:

    Kent, this is a far superior theory to the panspermia and convergent evolution concepts often used in SF to explain human or humanoid aliens on other planets. It also neatly disposes of STL travel time lags as all these civilizations would have started at the same time as ours. My hat is off to you, sir. Putting this one in my back pocket for future use (with due acknowledgment of course)!

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