Scientists Theorize Interstellar Object Oumuamua Could be Extraterrestrial Solar Sail

Much has been written about the unusual interstellar visitor "Oumuamua" that was discovered by the PAN-STARRS1 survey in October 2017. This object, the first ever to be recorded from outside our solar system, was quite a surprise and unlike any asteroids or comets we've seen before: oblong in shape with a peculiar 5:1 aspect ratio and spinning like a flywheel. Unusual as it may seem, it was soon concluded to be a somewhat peculiar but ordinary comet.

However, two scientists have now published a paper on arxiv.org highlighting some inconsistencies regarding the "comet hypothesis". The authors, Abraham Loeb (Harvard University) and Shmuel Bialy (Tel Aviv University), take a closer look at previous findings which interpret the non-gravitational acceleration in the motion of Oumuamua as "outgassing", which is typical for cometary activity.

They argue that, instead, the observed acceleration could be due to solar radiation pressure. However, for this to be true the object would have to consist of a very thin material. According to Loeb and Bialy, the geometry does not necessarily have to be that of a planar sheet, but may acquire other shapes, "e.g. involving a curved sheet, a hollow cone or ellipsoidal" (in order to account for the unusual "mass-to-area" ratio). When considering an artificial origin, they point out that one possibility is a light-sail floating in interstellar space as debris from an advanced technological equipment.


Artist's rendition of "Oumuamua"

Could Oumuamua Be an Extra-Terrestrial Solar Sail?

“We explain the excess acceleration of `Oumuamua away from the Sun as the result of the force that the Sunlight exerts on its surface. For this force to explain measured excess acceleration, the object needs to be extremely thin, of order a fraction of a millimeter in thickness but tens of meters in size. This makes the object lightweight for its surface area and allows it to act as a light-sail. Its origin could be either natural (in the interstellar medium or proto-planetary disks) or artificial (as a probe sent for a reconnaissance mission into the inner region of the Solar System).”

In summary, Loeb and Bialy try to find a better explanation for Oumuamua's rather strange properties, such as the aforementioned unusual "mass-to-area" ratio, its low thermal emission (high reflectivity) and the unprecedented axis ratio inferred from its lightcurve.

Considering that one of the authors has quite a track record, it would seem that we can't just ignore this theory and move on as if nothing happened. To be fair, the paper also mentions the possibility of a natural occurence of such exotic materials but the authors do not dedicate more than a sentence to these possibilities. This would suggest that their favoured interpretation points to an extraterretrial origin of Oumuamua.

As always, thanks a lot for reading up to here and I look forward to your thoughts on this!




SOURCES & LINKS:
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01. Related Paper published on arxiv.org
02. Paper by Shmuel Bialy, Abraham Loeb (PDF direct link)
03. Wikipedia article about "Oumuamua"
04. Website of Abraham Loeb (Harvard University)
05. More info about Shmuel Bialy (Tel Aviv University)
06. Previous ATS Thread about Oumuamua
07. Universe Today: Could Oumuamua Be an Extra-Terrestrial Solar Sail?

a reply to: jeep3r

Great find and great post! Heading off to see what else I can find on this. Very intriguing!

Broken chunk of Dyson grid has been my suggestion for an Oumuamua origin, since it was detected.

It made me do some serious research into events like the Nuremberg 1561 event, as possible debris fields from a Dyson object.
( I think 1561 was just planet/star/orbital misidentifications. I used a sky, field of view simulator to see the sky area mentioned for the date and time of the Nuremberg event. )

Several planets all came up, nearly lined up with the sun, that morning in Nuremberg.

Sad to come to non-alien conclusions, but reasonable to do so.

Oumuamua could still be either I guess. I coin flip artificial vs not, for Oumuamua.

Say it is a solar sail from an advanced civilization,

Is it just their "space junk" that has been floating around in interstellar for millions of years?

Wouldnt it take that long to get here from anywhere else outside of our solar system?

Very cool S and f.

A light sail would demonstrate a similar acceleration on the sunward (inbound) part of its trajectory, wouldn't it?

The authors do not seem to address that.

Oh dear! What conceits of the imagination some people who like to call themselves "scientists" come up with in order to explain what cannot be explained in conventional, scientific terms, viz., the recorded, non-gravitaionally-caused acceleration of Oumuamua despite no signs of outgassing! So now we are asked to believe in the existence of objects that are kilometres long but a fraction of a millimetre in thickness. What natural astronomical process created that?! Oh wait! Perhaps it was the long lost sail of an alien interstellar craft? Does Loeb et al really ask us to accept the possibility that aliens travel around in space hoping to pick up the radiation pressure of a nearby star? How crude and hopelessly impractical. Anyone who wants us to believe that should be forced to resign from his academic post as a proven crank. Come on, Loeb, why not admit it? You cannot explain this anomalous motion and have to resort to far-fetched interpretations in order to avoid the elephant standing in your office: ALIEN SPACECRAFT. Your proposal is a joke.

a reply to: Phage

To answer that question we'd probably require more details about the exact nature of the "non-gravitational acceleration" and how it influenced the trajectory of Oumuamua.

I haven't yet read all the cited works and I doubt that, even if I did, I'd fully grasp the implications.

I'm still not clear as to where the "sail" part is supposed to be. Wouldn't that be really big?

yep.... there's a lot more to that object from interstellar space/outside this Solar System

We were foretold that 'signs' in the Heavens will be shown humanity before the end-times unfold...

I refer the reader to the September appearance of the Revelation 12 'Sign', where the constellation Virgo (or to the prophets ~A Woman, bathed in the Sun/wearing a Crown of 12 Stars/ having the Moon at her feet~ fully accomplished these conditions & therefore became and end-time Sign of The Woman in the Heavens Sign-of-Wonder which also brought the Earth bound observers the Once-in-History, Rare-Object, called by the Prophets Sign of the Son-of-Man as an alien object which appeared in the Constellation Virgo then 'wooshed' past the Sun with increasing speed...(and outwards this solar system towards the constellation Pegasus...)


the combined Wonder-in-the-Heavens (Virgo birth sequence along with crown/Sun/Moon factors) together with the Son-of-Man Sign (AKA: Oumaumaua =distant stranger) gave followers of the prophecy a clue as to the present 'timeline' of Eschatology


the Hawaiian's got the name right, a strange visitor -> "Son-of-Man" sign -> the Hawaiian name lends an anthrophomoric air to the Alien Object, huh


open the Doors of Preception

a reply to: jeep3r

To answer that question we'd probably require more details about the exact nature of the "non-gravitational acceleration" and how it influenced the trajectory of Oumuamua.

In a nutshell, it was observed that Oumuamua did not slow down quite as much as it should have as it was leaving. That's what these guys are trying to explain as the behavior of a light sail. The trouble is that same behavior would cause it to not speed up quite as much as it should have as it approached.

a reply to: Phage

That would make sense, indeed. I just sifted through the paper that Micheli (et al.) published in September and came across this:

The detection of non-gravitational motion in the trajectory of ‘Oumuamua (Micheli et al. 2018) poses additional challenges in estimating its inbound asymptotic motion. In particular, the available astrometric dataset only constrains the detected non-gravitational perturbation from 1 au to 3 au on the outbound leg of ‘Oumuamua’s trajectory, while its effect on the inbound leg relies on modeling assumption.

Perhaps they implied that the inbound effect on the trajectory is based on modelling and thus less accurate? But you're right when pointing out that they could/should have mentioned that.

originally posted by: Phage
a reply to: jeep3r

To answer that question we'd probably require more details about the exact nature of the "non-gravitational acceleration" and how it influenced the trajectory of Oumuamua.

In a nutshell, it was observed that Oumuamua did not slow down quite as much as it should have as it was leaving. That's what these guys are trying to explain as the behavior of a light sail. The trouble is that same behavior would cause it to not speed up quite as much as it should have as it approached.

For one, it was tumbling, which in itself wouldn't account for everything, but if it had any internal movement that could act as a ballast it would do all sorts of fun stuff to it's orbit characteristics.
(Look into cargo ship, cargo liquification. It sinks ships.)

In addition to that, from a technological standpoint imagine a material that acts a solar sail depending on the characteristics of nearby gravitational forces. Such a material in theory could be made to decrease solar reflectivity as it approaches a gravity well, then increase it as it is moving away from that same gravity well.

A solar reflective material with a one way valve type action, would facilitate that. We certainly have materials with similar capability. Some material does this optically or electrically, that our little monkey brains designed. It is likely that we can construct material to do the same, under varying gravitational force. We use diodes in all sorts of fun stuff, including solar panels. They are electrical one way valves.

Such a material would be a fantastic, passive thruster. No exhaust. Negligible loss of material. No need for giant fuel tanks. So many positives to such a material, with a pre-planned trajectory it would probably be a preferred method.

Original: Queen’s University Belfast/William Herschel Telescope

From OP's link at Universe Today.

I think somebody said that humans never saw the thing... well, not so.

It would be a very civilized method to go spy on your neighbor. Instead of a drone, send a space rock. Unless it was detected as heading right at you, you would only see it as it flew away. If one were smart enough to recognize it as extra-solar, then a little bread crumb of "unexplained acceleration" would make sense too. A wink and a smile to say, "We know you saw. What can you do?" *shrug* Instead of landing on the Whitehouse lawn and what not ("Whycome country A instead of ours?"). Find out what level of technology the place is at.

Of course, it could be made of dark matter! lulz! pfftt! *chortle* *snort*

Anyway, strange space rock to say the least! Thanks OP! At least it didn't come from a conspiracy website or late nite talk radio!

PS - The photo I saved to my desktop is "Oyoumamma.png"!! Kind of shows you what a loopy day of work does to TEOT.

a reply to: Phage

I suppose different sides could have different material causing different reaction to light?

a reply to: jeep3r

Great job! Thanks for posting. Unfortunately I have nothing to add to the debate regarding this object.

On a side not, as some other poster has noted a "rock" would make a great spy drone. Or any type of space ship for that matter. Something I have always pondered.

They are readily available - more or less. They can be cored out and built to suit. The mass of the rock on the outside shields from radiation. No need for force fields when the Klingon's attack, the mass of the rock can absorb a ton of energy. Easier to hide from the Empire too.

a reply to: jeep3r

It's a bloody ROCK.

a reply to: mekhanics

Yes, they said it was dark red. DUH

Of course it was blood.

I'd have to ask [citation needed] though.

No one got optical images of it. Good luck proving that it wasn't a Happy Meal fry floating through space, without evidence, nor counter evidence.

You're just as full of yourself as someone spouting it's a space-ship.

a reply to: mekhanics

You heard it here first folks......it's a bloody rock. Who's blood is it? We are yet to obtain a sample. Where did the blood come from? We are yet to obtain a sample. How did the blood get there? We are yet to obtain a sample.

mekhanics seems to be in the know though....maybe he can shed some more light on his assertion.

a reply to: jeep3r

Star and flag, i'm an harvard scholar now because apparently degrees can thrown around like confetti.

Humanity has developed an ion drive, theorized the Von Neumann probe, the solar sail is primitive compared to our new understanding of our expansion into the cosmos. Voyager had less computational power than your first smartphone at yet it's exited our solar system due to a gravity slingshot, and it matched half the speed of these theoretical solar sails.

Not to mention this...cosmic yacht can fly across the galaxy and no electronic signals can be detected? I appreciate you for bringing this news to us, but seriously speculation is fine if it's based on established facts. I've seen some weird crap, but I wont write a treatise on it, i will speculate.

a reply to: Thecakeisalie

Voyager had less computational power than your first smartphone at yet it's exited our solar system...,

Well, not exactly, Voyager 1 won't even reach the Oort Cloud for another nearly 300 years, and it will take another 30,000+/- years to pass through it. Only then will it have truly "exited" the "Solar System".

However, I get what you were driving at with your post.