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It's not rocket science, it's...
The Final Frontier
The abyss stares back

ʻOumuamua (Hawaiian for "scout"), object catalog 1I/2017 U1, which at least doesn't sound so weird, is the first known interstellar object discovered while crossing our Solar System.

A few otherwise well-qualified individuals have suggested it might be an alien spacecraft or some other kind of alien artifact, based on its trajectory and measurements suggesting it may be accelerating — although none of the evidence is anywhere near conclusive, and there are alternative natural explanations.[1]

Discovery and trajectory[edit]

ʻOumuamua was discovered in October 2017 with the Pan-STARSS telescope after its closest approach to the Sun. After having classified it as yet another unremarkable asteroid or comet, it was recognized as a body coming from outside the Solar System the following month once earlier images of the same object were found from digging through archives of images taken with other telescopes.[2] It was concluded that, unlike standard comets or asteroids, there was no way that a Solar System minor body could have such trajectory and relative speed.[3]

Its trajectory brought it from the direction of the Lyra constellation[4] and after approaching the Sun closer than the orbit of Mercury[5] and receiving a boost on its speed, it's on course towards the Pegasus constellation.[6] It is also estimated that it will leave our Solar System within 20,000 years.


Giant space coprolite from nowhere Artist's impression of ʻOumuamua

Due to its faintness and small size, very little is known of ʻOumuamua. It has been suggested it could have come from a stellar association of young stars located 300 light-years from us,[7] or be either a small chunk of a planet that got shredded by a star,[8] or an asteroid ejected from a dying star system,[9] but for all intents and purposes its origin is unknown and it could have well roamed the Milky Way for countless millions of years.

Measurements of ʻOumuamua's spectrum suggests it's a very red object similar to other outer Solar System bodies such as certain asteroids or comets.[10] Its size is not well determined but it's estimated to be roughly a battleship-size turd highly elongated in the range of around 200 meters[11] in chaotic rotation with a period of around 8 hours.[12] More recent findings suggested ʻOumuamua could be not an asteroid but a mildly active (still interstellar) comet instead, since it appears that it's outgassingWikipedia material after passing close the Sun and it giving a very small acceleration.[13]. Later studies, however, dispute that claim because if it worked like Solar System comets, it would have broken apart (so is not a comet, neither is it an asteroid).[14]

It has been proposed to send a probe to ʻOumuamua,[4] but sadly even if we had technology to move a spacecraft so fast (ʻOumuamua's relative speed gives a run for their money to our current spacecraft propulsion technologies), given the way things work with space agencies — read: limited budgets and lots of bureaucracy — it's unlikely to happen.


Funny and harmless comparisons have been made with the starship "Rama", which appears in Arthur C. Clarke's novel Rendevous with Rama,[15] including that both "Rama" and ʻOumuamua are highly elongated.

ʻOumuamua has also been linked to Nibiru/Planet X by pseudoastronomers,[16] which has been incorrectly predicted to arrive in the Solar System multiple times, including some predictions that were at least in the same year as ʻOumuamua (never mind that it did none of the things Nibiru were predicted to do).

Not woo[edit]

Some astronomers have proposed ʻOumuamua could actually be a solar sailWikipedia (read: a spaceship) attempting to explain how it's accelerating outward as mentioned above.[17] However others have contested that, as data is pretty much insufficient[18] and as commented above the probability of a spacecraft being sent to study it pretty much nil.

External links[edit]


  1. Avi Selk, Harvard’s top astronomer says an alien ship may be among us — and he doesn’t care what his colleagues think. The Washington Post, 4 Feb 2019.
  2. A brief visit from a red and extremely elongated interstellar asteroid
  3. JPL Small-Body Database Browser: 'Oumuamua (A/2017 U1)
  4. 4.0 4.1 "Project Lyra: Sending a Spacecraft to 1I/'Oumuamua (former A/2017 U1), the Interstellar Asteroid"
  5. Interstellar Asteroid FAQs
  6. Pseudo-MPEC for A/2017 U1 (FAQ File)
  7. "Origin of Interstellar Object A/2017 U1 in a Nearby Young Stellar Association?
  8. 1I/`Oumuamua as a Tidal Disruption Fragment From a Binary Star System
  9. Ejection of material --"Jurads" -- from post main sequence planetary systems
  10. 1I/'Oumuamua is Hot: Imaging, Spectroscopy and Search of Meteor Activity
  11. Interstellar Interloper 1I/2017 U1: Observations from the NOT and WIYN Telescopes
  12. APO Time Resolved Color Photometry of Highly-Elongated Interstellar Object 1I/'Oumuamua
  13. ESO's VLT Sees `Oumuamua Getting a Boost - New results indicate interstellar nomad `Oumuamua is a comet.
  14. Spin Evolution and Cometary Interpretation of the Interstellar Minor Object 1I/2017 'Oumuamua
  15. The first discovered interstellar asteroid is a quarter-mile long red beast
  16. Holy Smokes: Lost asteroid shaped like a Cigar becomes our first interstellar visitor from another solar system after wandering for hundreds of millions of years: The dark red object named Oumuamua is the first space rock from outside the solar system ever observed by astronomers by Maryse Godden (20th November 2017, 8:21 pm | Updated: 21st November 2017, 6:01 pm) The Sun. See comments from November 21st.
  17. Could Solar Radiation Pressure Explain 'Oumuamua's Peculiar Acceleration?
  18. Scientists push back against Harvard 'alien spacecraft' theory