Oumuamua seems a perfect copy of such suggestions. But we shall never know.
Tullio

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It sure reminded me of "Rama" from Clarke's "Rendezvous with Rama" ...

It sure reminded me of "Rama" from Clarke's "Rendezvous with Rama" ...

I think I made this observation early in this thread.

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Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.

The interstellar mystery?

'Oumuamua one year later

One year ago this week astronomers discovered an unusual object moving through space not too far from the Earth's orbit. In just a few days they realized it could not be a normal asteroid or comet – its path showed that it was not gravitationally bound to the solar system. It was, therefore, the first interstellar body ever discovered in our solar system that originated from outside it. It was given the Hawaiian name 'Oumuamua, "scout."

https://phys.org/news/2018-10-oumuamua-year.html

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ASTRONOMERS spotted something odd last year. Something really odd. Now a Harvard professor suggests it was an alien solar sail sent in search for life — ours!

We might not be alone?


IT WAS our first known interstellar visitor when it was detected flashing past the Sun in October last year. Dubbed ‘Oumuamua’ — Hawaiian for messenger — it was quickly determined to be not of this solar system.

Its trajectory had been traced. And the track it was on could not have possibly been an orbit around our Sun. So it must have come from deep space.

Follow-up observations after the Pan-STAARS-1 telescope in Hawaii announced its discovery revealed the object to be odd.


Oumuamua: Harvard researchers suggest strange interstellar object may be alien light sail

Edited to add another link.

https://www.dailymail.co.uk/sciencetech/article-6347379/Interstellar-asteroid-Oumuamua-giant-solar-sail-sent-civilization.html

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I know you and papers, Chris. It is believed the object had a high metal content.


Could 'Oumuamua be an extraterrestrial solar sail?


On October 19th, 2017, the Panoramic Survey Telescope and Rapid Response System-1 (Pan-STARRS-1) in Hawaii announced the first-ever detection of an interstellar asteroid, named 1I/2017 U1 (aka, "Oumuamua). In the months that followed, multiple follow-up observations were conducted that allowed astronomers to get a better idea of its size and shape, while also revealing that it had the characteristics of both a comet and an asteroid.

Interestingly enough, there has also been some speculation that based on its shape, 'Oumuamua might actually be an interstellar spacecraft (Breakthrough Listen even monitored it for signs of radio signals!). A new study by a pair of astronomers from the Harvard Smithsonian Center for Astrophysics (CfA) has taken it a step further, suggesting that 'Oumuamua may actually be a light sail of extra-terrestrial origin.

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The new scientific paper by Harvard astronomers Bialy and Loeb, entertains the possibility that interstellar space object Oumuamua is a extraterrestrial artifact. It is interesting not only for what it says, but the way it is said.

They attempt to explain the ascertained fact that Oumuamua is leaving our solar system at a velocity higher than can be explained, even after the speed derived from its relatively close passage by the Sun is considered. They also entertain other sources of the excess speed, including comet-like outgassing. They found that this would have changed the spin of the object, something that was not observed.

Pressure from solar emissions could have impelled the object to the observed velocity, but only if the object were an extremely thin layer of material. This is the basis of the speculation about a light sail. It's not an unreasonable inference, under the circumstances. Part of the value of this scenario is that its physical validity can be, and is, shown mathematically.

Another point in its favor is that is also allows speculation about some unknown natural interstellar material of extreme thinness. There is no other evidence for such material, and not even a theoretical basis for its existence, but like the light sail, it is physically possible, albeit of a very low probability.

The authors of this paper also raise the possibility of an interstellar probe intentionally sent our way. This, too, seems quite reasonable. One need only consider what the appearance of Oumuamua, at this time, implies.

Very shortly after we became able to observe such objects in a systematic way, we find one. For this to be at all likely for a natural object, there must be a heavy rain of such bodies pouring between the stars. Such a torrent would vastly exceed that supported by our observational experience and astrophysical models.

A link to the scientific paper is provided below:

https://arxiv.org/pdf/1810.11490.pdf

Thanks for the compliments, Chris.

It's not reasonable that professional astronomers would neglect the accelerating effect of the Sun in their calculations, and make a mystery out of nothing. Even allowing for that acceleration, Oumuamua has since slowed less it should have done. Another source of propulsive energy is obviously present. No other scientist has disputed that, to my knowledge.

An artificial extraterrestrial object may be just a possibility, but given the failure of other explanations, it seems a quite reasonable one.

'One in a bilion' coincidences are remarkably rare. Invoking them doesn't make for a convincing explanation in science. To render the odds more reasonable here, it would be necessary for an exceptionally high number of interstellar comets and/or asteroids to be present throughout space. Yes, our sense of how objects are boosted out of their home star systems could be radically wrong, but we have no solid base for such speculation.

By the way, reputable journalists don't simply tell the public what it wants to hear, but try their best to get at the facts of whatever matter they're investigating. A number of reputable mainstream and scientific news sources have covered the release of the Harvard astronomers' new paper, without making charges of bias or error.

The authors wrote also in the paper.

Since it is too late to image ‘Oumuamua with existing telescopes or chase it with chemical propulsion rockets, its likely origin and mechanical properties could only be deciphered by searching for other objects of its type in the future. In addition to the vast unbound population, thousands of interstellar ‘Oumuamua-like space-debris are expected to be trapped at any given time in the Solar System through gravitational interaction with Jupiter and the Sun. Deep wide-area surveys of the type expected with the Large Synoptic Survey Telescope (LSST)4 will be particularly powerful in searching for additional members of ‘Oumuamua’s population of objects. A survey for lightsails as technosignatures in the Solar System is warranted, irrespective of whether ‘Oumuamua is one of them.

Guess we have to wait for the next passage of ‘Oumuamua’s.

[humor] My biggest complaint is that those JPL party-poopers don't know how good yellow/sensationalist journalism works. If they just left home their Ockham's razors and stopped insisting   s̶o̶l̶a̶r̶ ̶s̶a̶i̶l̶s̶    extraordinary claims require extraordinary evidence, we would be living in a better world. [/humor]

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We're NASA scientists, asteroid and comet experts. Ask us anything about 'Oumuamua, our solar system’s first known interstellar object
https://www.reddit.com/r/IAmA/comments/8umfgw/were_nasa_scientists_asteroid_and_comet_experts/
submitted 4 months ago * by NASAJPL

"Using observations from NASA’s Hubble Space Telescope and ground-based observatories, an international team of scientists confirmed ′Oumuamua (oh-MOO-ah-MOO-ah), the first known interstellar object to travel through our solar system, got an unexpected shift in trajectory as it passed through the inner solar system last year. Our team is ready to answer your questions today, June 28, 2018, from 4-6 p.m. ET (1-3 p.m. PT, 2000-2200 UTC). Experts will sign their responses."

June 27 news: https://go.nasa.gov/2ItHw5j

"What we know (and what we don't) about 'Oumuamua": https://go.nasa.gov/2N5f3WY

Proof: https://twitter.com/NASAJPL/status/1012430331545190401

Marco Micheli, astronomer, lead author, ESA Space Situational Awareness Near-Earth Object Coordination Centre
Marc Buie, co-author, institute scientist, Southwest Research Institute
Davide Farnocchia, co-author, asteroid and comet scientist, NASA Jet Propulsion Laboratory
Karen Meech, co-author, astronomer and graduate chair, Institute for Astronomy
Kelly Fast, Near-Earth Object Observations Program Manager, NASA Headquarteres
Paul Chodas, co-author, manager, Center for Near-Earth Object Studies, NASA JPL

Social media & communications support:

Ryan A Bell, NASA JPL
Brittany Brown, NASA HQ
Calla Cofield, NASA JPL
Kaitlyn Soares, NASA JPL
Stephanie L. Smith, NASA JPL

[–]metalburning 15 points 4 months ago
What caused the shift in speed?

[–]NASAJPL[S] 28 points 4 months ago
Outgassing from vents on the surface of the object. It's a very small force, but our data was so precise that we could detect it. We think there are lots of frozen gases under the surface of this object, and when it got close to the Sun the surface heated up and those gasses sublimated and erupted through the surface, probably through vents. The Rosetta spacecraft actually imaged this sort of venting on comet 69P/CG. The outgassing occurs mostly on the daytime side of the object, because the daytime side is hotter. That's why outgassing generally pushes objects away from the Sun. That's what we say with `Oumuamua. -Paul

[–]NASAJPL[S] 15 points 4 months ago
Correction: Rosetta was at comet 67P/Churyumov-Gerasimenko, not 69P

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Apr 3, 1999 - May 3, 2020

From what I can see, the available evidence seems to be now about 70/30 in favour of an asteroid/comet previously unknown.

The remaining 30 percent being an alien probe/spaceship or a mote of dust on our glasses ? Sorry, I didn't fart; I outgassed.

Apologies to the tin foil hat brigade.

We're in good company, so I suggest we avoid demeaning terms such as the Art Bell squad and settle for the fearless intellectual daredevils' platoon.

Member of UCB Charter Hill Society

Please register me in your secret admirers' society.

Pierre A Renaud, FCD (a cheaper nobiliary particle indeed, but a glorious one nonetheless)

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Apr 3, 1999 - May 3, 2020

'Aliens' Is Not A Scientific Explanation For Interstellar Asteroid ʻOumuamua - Nov. 8, 2018
Ethan Siegel, Ph.D. astrophysicist, author, and science communicator
https://www.forbes.com/sites/startswithabang/2018/11/08/aliens-is-not-a-scientific-explanation-for-interstellar-asteroid-%CA%BBoumuamua/#34789c793719

It might be fun to imagine scenarios where aliens are responsible for phenomena that we aren't exactly sure how to explain with the present data we have, and perhaps it's worth keeping an open mind when it comes to their existence. But the whole point of doing science is to learn about the Universe the way it actually is, based on the evidence we actually have. As it stands, there are a slew of candidate, natural explanations for all of these phenomena that don't invoke new physics, exotic scenarios, or the intervention of aliens.

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Apr 3, 1999 - May 3, 2020

According to a new paper by Harvard scientists Schmuel Baily and Avi Loeb, it could have been due to an alien-created lightsail from a distant, extraterrestrial civilization. Although the idea has taken the world by storm, it's a shocking example of sensationalist, ill-motivated science.

In the case of interstellar interloper ʻOumuamua, we should be looking at the natural explanations first and foremost, not speculating about something for which the only evidence is our own wishful thinking. After all, what can be asserted without evidence can — and should — be dismissed without evidence.

+100

So many people wanted it to be evidence of ET (for various reasons) that they slewed the evidence accordingly. Simple fact :-

1. Nobody can prove it WAS an ET device of any kind.

2. Nobody can prove that it WASN'T.

It's up to the individual to interpret what results we obtained and make their own decisions as to what they think. Now that it has gone elsewhere we shall never know anyway, unless it comes back and says Hi.

Personally I'd rather attribute its slight funny in the "orbit" as the Pioneer Anomaly.

Dr. Siegel examines several explanations for the anomalous extra speed of Oumuamua. Most of these he dismisses as unlikely. He seems to find uneven heating, also known as the Yarkovsky Effect, the post plausible.

This seems odd, because the Yarkovsky Effect has been found to cause changes in position, due to changes in velocity, on the order of a few kilometers per year. Oumuamua was found 100,000 kilometers away from where it was expected to be, over a matter of months.

He also mentions the effect of solar radiation pressure, but that would have the observed effect only if the object were exceedingly thin, hence the 'light sail' suggestion by the Harvard University astronomers, Dr. Bialy and Dr. Loeb.

The Pioneer Anomaly does not appear to be applicable to a natural object. It is based on the heat produced by the spacecraft's own power source. If one wished, they could posit that an extraterrestrial spacecraft was accelerated in the manner of Oumuamua by thermal emissions from whatever source of power it used.

It doesn't make any difference whether it was a probe or vehicle or just a rock. We can't do anything about it now.

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Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.

It doesn't make any difference whether it was a probe or vehicle or just a rock. We can't do anything about it now.

'Oumuamua isn't that far yet; we could still receive or exchange recipes if it has a gastronomical library aboard (and at least a decent AM transmitter). I am presently listening to 16 Gbyte chunks of Green Banks RAW data, trying to detect the presence of extraterrestrial coffee-related information (essential for more glorious and marketable dawns).

If Ellie (Contact, 1997) can decipher hidden messages within such noise by using headphones, so can I. If you don't see me coming back here after a while, it just might be that, in the name of Citizen Science, I've gone insane (or got intoxicated by too strong a weird coffee recipe), at last freed from the awful, insufferable negativity oozing out of this very thread.

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Apr 3, 1999 - May 3, 2020

I'm sorry that my comment was interpreted as my having a negative attitude. I think of it as being realistic. I would jump for joy if a true first contact were to be announced to the public. I have participated in this project on and off since it went public so many years ago. At that time I was sure that this project would yield results that proved the existence of ET.

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Bob DeWoody

My motto: Never do today what you can put off until tomorrow as it may not be required. This no longer applies in light of current events.

On a more serious note:

NASA reveals new findings about 'Oumuamua, the 'alien probe' asteroid - November 14th, 2018
The Spitzer telescope looked for 'Oumuamua and couldn't find it -- but that doesn't mean it was sent by an alien civilization
https://www.cnet.com/news/nasa-reveal-more-secrets-about-oumuamua-the-alien-probe-asteroid/

The Spitzer telescope has a different pair of eyes to a traditional telescope, as it were, because it sees in infrared energy and thus detects a heat signature, rather than looking for reflected light. Though it is believed that 'Oumuamua has an elongated body, Spitzer cannot infer the shape of the object from its reading, but can make an estimate about the object's "spherical diameter". The study suggests it may be as small as 100 meters (320 feet), or as large as 440 meters (1,440 feet).

Importantly, placing size constraints on 'Oumuamua is central to one of the outstanding mysteries of the interstellar visitor -- the unusual speed boost it received as it sped past the sun. In June, a study suggested that if the asteroid was small enough, outgassing -- the release of gas trapped in the asteroid as it heats up -- may be responsible for the increased speed. Spitzer's observations certainly make that theory much more likely and effectively puts the "alien probe" theory to bed.

The article ends confirming Bob's sobering statement :

As the object continues its journey through space, away from the Earth, it gets further and further away from our telescopes so we're unlikely to get a handle on just exactly what 'Oumuamua is.

Like ships in the night, the Earth and 'Oumuamua are destined to carry on sailing across the cosmic ocean, never to meet again.

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Apr 3, 1999 - May 3, 2020

I'm sorry that my comment was interpreted as my having a negative attitude. I think of it as being realistic. I would jump for joy if a true first contact were to be announced to the public. I have participated in this project on and off since it went public so many years ago. At that time I was sure that this project would yield results that proved the existence of ET.

Don't worry, Bob. I wrote this entry tongue in cheek, and your pragmatism and restraint are qualities to be, imo, emulated.

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Apr 3, 1999 - May 3, 2020

Great links, Pierre! You are the link specialist around here. :~)

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The mind is a weird and mysterious place