Debunking The Shape Of Interstellar Asteroid Oumuamua

Note : This is a long article. For a short summary, please read my Twitter thread.

Date : June, 2018
(last updated in June, 2020)

Oumuamua Shape Debunked
Debunked not just Oumuamua's shape but also the "science" of shape estimation of asteroids & comets.

Just to clarify, the super elongated shape of this interstellar asteroid called Oumuamua has NOT been seen by any human eyes or instruments. There is no visual evidence for the shape. The best instruments just saw a tiny moving dot of light in space. The asteroid was too far away & too small for its shape to be detected in any way. And yes, its visual was just an illustration, not a photograph. 

But how did the scientists then arrive at that shape ?

Left : The best instruments just saw a tiny dot. Right : Estimated shape of Oumuamua.
Credit : ESO, M. Kornmesser, ESA/Hubble, NASA.

By using a technique called Lightcurve Analysis, where the brightness variation of the reflected sunlight from the asteroid or comet is plotted over time & the result is a cyclical curve, from which the scientists estimate the shape of asteroids & comets.

 The “lightcurve” of ‘Oumuamua, showing brightness variation over time. Credit : ESO/K. Meech et al.

Simulation of Oumuamua spinning and tumbling through space, and its light curve. 
Credit : NagualDesign, from Oumuamua wiki page

But predicting the shape of an object by
looking at a tiny dot of fluctuating light is
NOT genuine science ! 

I have explained why, below.
Please give it a patient reading.

How The News Started

1) The press release given to media (dated Nov 20, 2017) by European Space Observatory, makes a fantastic claim (without a fantastic evidence to back it up) :

) The original research paper of the scientists (dated Nov 1, 2017), is more subdued & doubtful :

The uncertainty of the scientists about the asteroid shape, expressed in their research paper (link 2), got diluted / omitted in the press release (link 1) and diluted further more by the media, reporting the news. This is how the story evolved : 

While no one claimed that the cigar shape is an absolute truth, it got published & accepted as such, by almost everyone.

Cigar Shaped Oumuamua

The European Space Observatory has published 3 versions of the same object, so far :

1) very long sensational version, with width to length ratio of 1:10, in grey color (even NASA believed this to be true)
2) a revised shorter version, 1:6  in grey color  (even The Astrophysical Journal estimated it to be 1:6)
3) short version, 1:6, with a revised brown-red color, instead of grey.

Credit : ESO, M. Kornmesser, ESA/Hubble, NASA

4) In the latest version, ESO goes back to grey rock. They sure seem very confused on Oumuamua's shape & color. Lot of flip-flops. All these visuals seem more like wild speculations rather than genuine science. If you dish out multiple estimates, surely one will click. Here is NASA's version of the cigar shaped asteroid.

 Credit : NASA/JPL-Caltech

Anyway, even the 1:6 cigar shape illustration is bogus, not at all supported by any evidence of past observed shapes of asteroids & comets. None of them are shaped like a cigar or a pillar or so abnormally slender. And the maximum width-to-length ratio observed so far, has been around 1:3, for Asteroid 433 Eros. A close 2nd is Asteroid Itokawa with a ratio of 1:2.5. I have ignored the dog-bone shaped Asteroid 216 Kleopatra (supposedly having a ratio of 1:2.67), since it does not have photos taken from a spacecraft in close proximity. Data from Earth or Earth orbit is not as reliable as the former. There is no photographic evidence so far, of any asteroids or comets having an aspect ratio exceeding 1 : 3.

Left : 3d model of Asteroid 433 Eros, based on photos from spacecraft. Right : Asteroid Itokawa 
Right Credit : Japan Aerospace Exploration Agency (JAXA)

6 & 10 are not the only length estimates for Oumuamua's aspect ratio. There are multiple interpretations of its shape - 10 different width-to-length ratios, by different teams of scientists ! Just like beauty is in the eye of the beholder, Oumuamua's length seems to be in the mind of the beholder :-)

 1 : 10  Meech et al  (2017)
 1 : 8.4  Eric Gaidos  (2017), 4.2 x 2, contact binary
 1 : 6.9  Bolin et al  (2017), 4.1-6.9, paper v2
 1 : 6.3  Jewitt et al  (2017)
 1 : 5.3  Bannister et al  (2017)
 1 : 5  Fraser et al  (2017), Avi Loeb (2018)
 1 : 4.63  Drahus et al  (2017)
 1 : 4.1  Bolin et al  (2017), 4.1-6.9, paper v2
 1 : 3  Knight et al  (2017)
 1 : 2  Seligman et al  (2020)

Width-to-length ratios of Oumuamua & the corresponding names of scientists who gave it, along with links to their research papers. 10 different cigars from 1 lightcurve method !

So, who is right ? Who is misinterpreting the data ? Whom should we believe ? How did the peer review community approve such extreme variations (from 2 - 10) & wild speculations ? And even if one of them is ever proved right, then it means all the others were wrong & so was their math, "science" & interpretations. 

Math is like water. It can be made to fit the shape of any container / conclusion. As seen above, math can give you any desired shape of Oumuamua, logic be damned. Lot of folks in the scientific community & the public, mistakenly think math is science, when it is not. Perhaps, they need to re-read the definition of science.

 My twitter thread :

The elephant & the 6 blind men - multiple interpretations of one reality.
Credit : Hans Moller 

It is funny when people say Oumuamua has a strange shape. Its shape is not strange bcos nobody knows its shape ! The ONLY real evidence we have, is the brightness variation of a tiny dot of light. Shape is just an INTERPRETATION of that, based on many assumptions, with inconsistent, incomplete & uncertain data. Oumuamua's estimated shapes cannot be considered as evidence or fact at all. And we know that interpretations can be very wrong, despite correct observations - the sun revolving around the earth was considered as a fact, for a long time.
Pancake Shaped Oumuamua

As if 10 length estimates for a cigar shaped asteroid were not enough, now scientists are saying that its shape can also be an oblate spheroid (pancake). They sure are covering their bases well, lest they be proven wrong, at a later time.

Left Credit : Dr. William K Hartmann. Right Credit : NASA/STScI 

A red, pancake-shaped Oumuamua is shown here - and here is a TED talk video (Feb 2018), highlighting the above shape - A team of scientists felt the asteroid is not just spinning but is tumbling and to explain this, they proposed in this research paper that Oumuamua can be either cigar shaped or pancake shaped, depending on whether its main spin is along its length or width, with a secondary spin on the other axis too. But spinning & tumbling were already shown by a cigar shape estimate. Why is pancake shape even needed ? How can one lightcurve method produce 2 extremely different shapes ? It is as ridiculous as saying that the Earth can be both spherical & flat, depending on its spin.

Animation credit : NASA/STScI

Shown above is NASA's pancake shape & they are also amazingly claiming that Oumuamua can be both shapes, but a pancake shape means that the asteroid is not elongated at all, as strongly claimed all this while, by the space experts. Just like 2+2 cannot have multiple answers, Oumuamua cannot have multiple shapes ! If scientists are sure the lightcurve method is genuine science, then why predict multiple shapes ? Multiple shape estimates indicate a wild guessing game. The standard procedure is just ONE shape estimation per asteroid / comet, as this asteroid database shows.

Also, note the color differences between Dr. William K Hartmann's version & that of NASA. Why this confusion, similar to the grey vs. red color of the cigar shape ? Anyway, even the pancake shape is bogus, not at all supported by any evidence of past observed shapes of asteroids & comets. Predicting 2 extreme shapes like cigar & pancake, is like saying heads I win, tails you lose, in a coin toss. You can claim victory either way !

The shape of Oumuamua has to be treated as unknown. 

Cigar & pancake shapes are wild speculations, not science, although, the pancake shape is far more believable. But one negates the other & the entire "science" behind it.

Since we are speculating ...  a pancake shaped asteroid city !
Credit : D.C. Thomson & Co. Ltd.

SpaceX's Oumuamua

The lightcurve data of SpaceX 2nd stage rocket + Tesla car, is now available. The electric car is permanently attached to the rocket and is orbiting the sun, roughly near Mars orbit.This is a real cigar-shaped, man-made Oumuamua. 

SpaceX Tesla Roadster : The width to length aspect ratio of the above combo is roughly 1:5. The rocket & car are orbiting the sun, as one unit.
Animation credit : SpaceX

SpaceX Tesla Roadster (Starman, 2018-017A) is rotating with a period of 4.76 minutes
Credit : Erik Dennihy (@UNC)

Can someone please estimate the shape aspect ratio from this lightcurve data ? This would be the ultimate test to check if the lightcurve method is genuine science or not. I strongly suspect that scientists will get it wrong again, bcos it is not just super elongated but the material is unevenly shiny too. See the original news about man-made Oumuamua and its lightcurve news.
Can the lightcurve predict the shape & aspect ratio correctly ?

6 Spectacular Failures Of Lightcurve Method

(of asteroids & comets)

Other Culprits For A Weird Lightcurve

It is very naive to assume that shape is the only explanation for a strange lightcurve. 

1) Unevenly distributed surface material can also explain it, like in the case of Saturn's two-faced moon Iapetus :

Credit : NASA/JPL/Space Science Institute

Similar data points for both but wild & sensational speculation for Oumuamua.
Left : points on curve are original but I replaced the original dotted curve with the curve from right, to show how curve suggestions can easily mislead you, despite same data.
Comparison chart credit : Vinny Chirayil

In the following article, astronomer Phil Plait, at least entertains the possibility of the asteroid being shorter than what is claimed, along with considering surface materials -

"As a note, it's worth mentioning that it's possible it's not quite this extended. If its coloration is patchy, with darker and lighter spots, then that can cause a more extreme brightness variation as well. It's entirely possible this object is therefore not quite as elongated as all that. Still, it's almost certainly longer than it is wide by a good margin."

In the same article, he says that the speed of spinning of an asteroid or comet tells us about what it is made of - "Some asteroids are rich in metal, and extremely tough. Some are rock, and more brittle. Others are "rubble piles," essentially shattered rock held in place by its own gravity and weak electrostatic forces. A metal asteroid can spin very rapidly without issue, but try that with a rubble pile and it'll fly apart."

Hence, a wrong shape estimate of the asteroid Oumuamua also leads to misunderstandings on its composition and strength. It
sets off a chain reaction. 

2) Asteroids / comets can be binary, trinary or more. They can have single or multiple moons too.  A large asteroid / comet can also break into smaller chunks, all of which can affect the lightcurve.

Left : Binary asteroid 243 Ida. Middle : Trinary asteroid Elektra.
Right : Radar image of asteroid Florence, with 2 moons. Credit : NASA / JPL

Credit : NASA, ESA, D. Jewitt (UCLA)

The above asteroid P/2013 R3 was luckily close enough for us to see the smaller fragments. Had it been very far away, then even our best instruments would have identified the asteroid to be 1 rock, even after breaking up. The break up would have just looked as a brightness fluctuation. In fact, scientists initially thought this asteroid was 1 piece, but it turned out to be 3 pieces, which eventually broke up into 13 pieces. 

So, at large distances when our best instruments barely see a tiny flickering light from earth or earth orbit, then the above realities can remain undetected and easily mislead us to very wrong conclusions. 

While the lightcurve method has its uses, using it for shape estimation is pseudo-science, kind of like astrology.

Scientists Speculating About Aliens

Just as I had accurately predicted in Nov 2017, wild speculations about alien spacecrafts soon popped up, even among the scientists, due to the claimed super elongated shape. An ordinary asteroid shape would not have triggered such speculations in the scientific community, as this research paper confirms - "Except for its unusually elongated shape, 1I/2017 U1 (Oumuamua) is a physically unremarkable ... object from another planetary system."

How to make tall claims, without evidence and then strengthen the claim, via distraction ? A reputed peer-reviewed science journal like Nature, shows you how. Its a classic !

Covers of the 1973 novel, Rendezvous with Rama
Rama spacecraft has an aspect ratio of just 1:3 only.

By the way, spacecraft Rama's dimensions in the novel were 16x50 kilometers, which works out to just 1:3 ratio. In comparison, Oumuamua's 1:6 & 1:10 estimates are plain ridiculous, going far beyond both science & science-fiction ! And Oumuamua is also mentioned on Rama's wiki link above, when it has no business being there, without a shred of evidence to justify such a link up. Clearly, we live in sensational times !

More such speculations in the media, by the scientific community :

1) Oumuamua is an alien probe with BROKEN engines, says leading astronomer
2) Could it really be ‘first contact’ ? Some credible scientists say there’s a genuine chance
3) Theoretical physicist Stephen Hawking believes Oumuamua could be alien mothership
4) Alien Probe or Galactic Driftwood? SETI Tunes In to 'Oumuamua
News report - of Abraham (Avi) Loeb's alien suggestion

Harvard scientist Abraham (Avi) Loeb's "alien" research paper (linked above) seems to be just an Ad for the lightsail project Breakthrough Starshot that he is associated with - in fact, he is the chairman of the Advisory Board for the project ! The last line of his paper mentions that his study was partly funded by Breakthrough Prize Foundation, part of the same company group. His paper was a clever but almost deceitful way just to introduce their name. I think this is a total mockery of peer review system & is dishonest science, with a vested interest. Conflict of interest is another way to describe it. A lightsail company's ad is disguised as a scientific paper. 

Avi Loeb does not mention at all how the lightcurve data of Oumuamua predicts a super thin object. What he proposes in his paper does not seem to have any connection to Oumuamua and did not need it at all. He cleverly piggy backed on it for publicity. Even scientists say there is absolutely no way to reproduce the observed lightcurve of Oumuamua with a solar lightsail, even if it is tumbling.

Imagine a top doctor publishing a medical research paper, purely with the intention of mentioning in it, the name of the pharma company that is partly funding the doctor's research, to give them publicity. And as if this wasn't bad enough, the doctor happens to be the chairman of the advisory board to the same pharma company, a person with a vested interest ! Both the doctor & pharma company stand to benefit from the media attention. Avi Loeb's paper on Oumuamua was exactly that, but in a different field. I hope you understood the degree of his unethical behavior.

Problem Of Blind Faith In Peer Review

Oumuamua's fantastic length, shape & status (whether asteroid or comet) were published in reputed peer-reviewed science journals :

Nature (cigar shaped, length about 10 times its width, 1:10 ) -  

Extract - "Light-curve observations indicate that the object has an extremely oblong shape, with a length about 10 times its width ... No known objects in the Solar System have such extreme dimensions. "  

2) The Astrophysical Journal (cigar shaped, length about 6 times its width, 1:6 ) -

Extract - "A 1:6 axis ratio is extreme, relative to most small solar system asteroids ... Except for its unusually elongated shape, 1I/2017 U1 (Oumuamua) is a physically unremarkable, sub-kilometer, slightly red, rotating object from another planetary system."

3) Astrophysical Journal Letters (pancake shaped, length about 6 times its width, 1:6 ) -  from the journal site.

Extract - "We find that ‘Oumuamua is “cigar-shaped”, if close to its lowest rotational energy, and an extremely oblate spheroid (pancake) if close to its highest energy state for its total angular momentum."

4) Nature journal says Oumuamua IS a comet -

Extract - "Mysterious interstellar visitor is a comet". That is a fantastic claim, without fantastic evidence to support it. A mismatch between the predicted & actual exit position of Oumuamua in the solar system, and some strange interpretations, cannot replace the hard evidence needed to classify something as a comet. The scientists now seem to be ignoring all the arguments made in support of Oumuamua being an asteroid, in the research papers originally published, in the science journals.

5) Research paper says Oumuamua IS NOT a comet - (see its media story)

Extract - "Oumuamua did not reveal direct signs of outgassing ... However, given the highly elongated shape of the object ... we conclude that the classification of 'Oumuamua as a comet is questionable."

The above research paper feels that the cometary classification is wrong but strangely, it has no doubt on Oumuamua being highly elongated. Looks like the peer review community blindly believed the tall claims about a super long asteroid. Also, according to Nature journal, Oumuamua was an asteroid in Nov 2017. Just 7 months later, the same clueless science journal magically transforms it into a comet !

Scientific American (part of Nature Publishing Group) claims to be world's premier magazine & an authority on science and technology for a general audience. And yet, it peddles the ridiculous & flawed interpretation of 1:10 ratio, as a fact. See the proof. Headline - 6 Strange Facts about the Interstellar Visitor Oumuamua. Extract of fact no.4 : "...This implies that ‘Oumuamua has an extreme elongated shape with its length at least five to 10 times larger than its projected width.". Looks like even reputed science media like Scientific American & Nature, have a tabloid DNA. Its shape is a wild speculative interpretation only. It is ridiculous & unscientific to call it evidence or a fact ! Maybe, the magazine should be renamed as Unscientific American !

What is the credibility of peer review, when their narrative has so many flip-flops & relies on a pseudo-science method for shape estimation ? The peer review community seems clueless on whats going on, with the interstellar object Oumuamua.

Oumuamua has shown the scientific community to be the King of Flip-flops.
Credit : Vinny Chirayil 

Clearly, the peers were just blindly approving, not reviewing. Peer review system has many flaws & should not be given undue weightage. One thing is clear - scientists are making use of every opportunity to make tall, sensational claims and stay in the news. Hard evidence no longer seems to be needed in science.

My lightcurve analysis of Oumuamua story :
Comparison layout credit : Vinny Chirayil


I have come across people who are still not convinced by my arguments & still believe in the fictional cigar shape of Oumuamua just bcos scientists said so, as if they cannot be questioned or debunked. Science is about evidence and fantastic claims need fantastic evidence too. Else, the claim of the scientists needs to be questioned, since science is also about questioning. Science is not about blind faith or worshiping the scientists.

And science is not the sole copyright of only the PhD holders either, like many ignorant folks seem to believe.

 “Science cannot belong only to scientists.

It’s part of how we understand ourselves
and the world. It’s for everybody.”

- Astrophysicist Janna Levin
Director of Science at Pioneer Works

Space experts might argue that the lightcurve based shape estimation method will not be an exact match to the real shape, and that one has to look at it more like a shrink wrapping, around the core shape. Ok fine, but that still does not explain the 6 spectacular failures listed earlier in this article or the contradictory cigar, pancake & solar sail shapes. 


One object but multiple shapes & colors - Good entertainment, definitely not science !
Credits : ESO, M. Kornmesser, ESA/Hubble, Dr. William K Hartmann, NASA/STScI.
IKAROS solar sail - Andrzej Mirecki 

Predicting shapes of asteroids & comets, based on the lightcurve method, is pseudo-science and it has a very pathetic track record, with 6 big failures to its credit already. A light flicker cannot possibly tell you the shape of the object causing it. It is definitely NOT science or even an evolving science ! Such estimations are just wild speculations & provide good entertainment in cases like Oumuamua.

Hence, the shape of Oumuamua has to be treated as unknown & this should be clearly mentioned below whatever visuals are used in the media, to depict it. But i
f you are still convinced that it is a genuine science, then -

1) please present 6 spectacularly successful shape estimations, which do not involve any use of radar data but is done purely using lightcurve data. And show a comparison of it, next to the photos of the asteroid / comet, clicked from a nearby spacecraft (asteroid Bennu's case does not count, since its shape was predicted successfully by radar observations).
2) please explain why the lightcurve method failed spectacularly in the 6 cases I have already mentioned.
3) please correctly predict the shape & axial ratio of SpaceX's Oumuamua from its lightcurve, without cheating.

I look forward to an intelligent rebuttal from the audience or even from the most competent space experts & science journalists. Should be interesting to see their response.

NOTE : I am just a space enthusiast (a nobody in space science) and did this analysis of the Oumuamua story, sitting at home with just an internet connection. Not bad for an "armchair scientist" as some have called me :-) 

I did not need a PhD in astrophysics to debunk this shape. But surprisingly, people with big qualifications & experience in space science, did not question the Oumuamua shape and quietly went along with the official fairytale spoon fed to them. I have not come across a single criticism anywhere, of its shape or of the pseudo-science method used to get it. They blindly believed the cigar-shaped fantasy. This herd mentality is very strange indeed !

Feel free to comment, agree / disagree
& even post links relevant to the topic.


(I had debunked the "science" of shape estimation of Oumuamua, as early as Nov 2017 and had posted it as comments on various Flipboard articles & Youtube videos. This article is a more detailed & visual version of the original set of posts.)



  1. An eloquent rebuttal I must say. So what is YOUR explanation for the 2.5 magnitude differential in the lightcurve?

    1. Thank you for going thru the article. I don't have an explanation for the magnitude differential & it is not my focus at all. My point is that a light flicker cannot possibly tell you the shape of the object causing it. Cigar & pancake shape estimations are wild guesses, not science. Hence, the shape of Oumuamua has to be treated as unknown & this should be clearly mentioned below whatever visuals are used in the media, to depict it.

    2. Why magnitude differential of 2.5 is absolute rubbish :

  2. It seems to me that we could obtain light curve signatures for known objects where we have both up close photos as well as telescope based observations. If they could obtain enough objects with comparative data, it seems to me they could come up with a range of likely shapes, based on similar light curve data to known objects. Thats about as close as we can get - a range of possible shapes solely based on known objects to compare to. By the way, excellent analysis.

    1. Gary, thank you for the feedback. I recently updated my article. Please have a look sometime.

      6 Spectacular failures of lightcurve based shape estimations