Astronomers conclude cigar-shaped interstellar object Oumuamua not an alien spaceship

Astronomers investigating the nature of a mysterious and apparently cigar-shaped object called "Oumuamua" spotted in 2017 speeding through our solar system, are confident it is not an alien spaceship.

After pouring over the data, an international team of researchers wrote that "we find no compelling evidence to favour an alien explanation."

However, the astronomers remain uncertain of how to classify the object.

Its odd shape and motion had prompted some scientists to wonder whether 'Oumuamua - the first object from another star system found passing through our solar system - was some sort of alien technology exploring the cosmos.

Scientists tracked the reddish-coloured 'Oumuamua from October 2017, until January 2018, after which it became too faint to detect even using the most powerful telescopes.

This artist's impression shows the first-known interstellar object to visit the solar system, 'Oumuamua, which was discovered on October 19, 2017. (REUTERS)
Reuters

It is estimated to be a half-mile long, tumbling through space.

"Our key finding is that 'Oumuamua's properties are consistent with a natural origin, and an alien explanation is unwarranted," said University of Maryland astronomer Matthew Knight, co-leader of the research published in the Nature Astronomy.

"Yes, if it made a sudden, unexplainable turn that would certainly have warranted further exploration," Mr Knight added.

'Oumuamua was first detected by the University of Hawaii's Pan-STARRS1 telescope. Its name in the native Hawaiian language means a messenger arriving from a great distance.

Knight said it is not easy to fit 'Oumuamua into familiar classifications such as a comet or asteroid.

"We have tried to avoid putting it in one of those boxes and prefer to call it more generically an 'object,'" Mr Knight said.

"In simple terms, asteroids are rocky and devoid of ices, while comets are a mixture of rock and ice, so-called 'dirty snowballs,'" Mr Knight added.

'Oumuamua was somehow ejected from a distant star system, traversing through interstellar space and through our solar system.

"It deviated slightly from a path that would be explained purely by the Sun's gravitational pull because of what some researchers said was apparently a very small emission of gas from its surface, indicative of a comet, though any such emission was so slight as to be undetected. It lacked a dust tail or gas jets, characteristic of comets.

The researchers wrote that a "straightforward explanation for 'Oumuamua is that it is a planetesimal" - a planetary building block - or a fragment of one - formed in faraway star system.

Its composition remains a mystery, including whether it is just rock or includes some metal or other ingredients. It is currently located beyond Saturn, dashing out of our solar system.

Agencies contributed to this report.

Amazing NASA Space Images - In pictures

1/61

Create a FREE account to continue reading

eros

Registration is a free and easy way to support our journalism.

Join our community where you can: comment on stories; sign up to newsletters; enter competitions and access content on our app.

Your email address

Must be at least 6 characters, include an upper and lower case character and a number

You must be at least 18 years old to create an account

* Required fields

Already have an account? SIGN IN

By clicking Create Account you confirm that your data has been entered correctly and you have read and agree to our Terms of use , Cookie policy and Privacy policy .

This site is protected by reCAPTCHA and the Google Privacy Policy and Terms of Service apply.

Thank you for registering

Please refresh the page or navigate to another page on the site to be automatically logged in