Skip to main content

Interstellar visitor ‘Oumuamua was a piece of Pluto-like planet, not aliens

This painting by William K. Hartmann, who is a senior scientist emeritus at the Planetary Science Institute in Tucson, Arizona, is based on a commission from Michael Belton and shows a concept of the ‘Oumuamua object as a pancake-shaped disk
This painting by William K. Hartmann, a senior scientist emeritus at the Planetary Science Institute in Tucson, Arizona, is based on a commission from Michael Belton and shows a concept of the ‘Oumuamua object as a pancake-shaped disk. William Hartmann

In late 2017, a strange cigar-shaped object was spotted streaming across the sky and was subsequently identified as coming from outside our solar system. Named `Oumuamua, this object didn’t seem to fit with what we know about comets, and researchers rushed to study the unique find and uncover its mysteries.

Now, researchers from Arizona State University have brought together observations of the object and worked out what combination of ices would explain its mass and shape. They found that solid nitrogen ice, like that found on the surface of Pluto, would explain the object’s features. They also calculated how quickly chunks of solid nitrogen could be knocked off the surface of a body like Pluto and found it was likely that a chunk from another solar system could reach our own.

The researchers are now confident they can explain what the object was made of. “This research is exciting in that we’ve probably resolved the mystery of what ‘Oumuamua is and we can reasonably identify it as a chunk of an ‘exo-Pluto,’ a Pluto-like planet in another solar system,” the study’s author, Steven Desch, said in a statement. “Until now, we’ve had no way to know if other solar systems have Pluto-like planets, but now we have seen a chunk of one pass by Earth.”

This composition of solid nitrogen explains the object’s elongated shape as well, according to co-author Alan Jackson. “It was likely knocked off the surface by an impact about half a billion years ago and thrown out of its parent system,” Jackson said. “Being made of frozen nitrogen also explains the unusual shape of ‘Oumuamua. As the outer layers of nitrogen ice evaporated, the shape of the body would have become progressively more flattened, just like a bar of soap does as the outer layers get rubbed off through use.”

Although at the time, the object’s strange features made some people suggest it could be evidence of intelligent life, the researchers don’t think that’s likely.

“Everybody is interested in aliens, and it was inevitable that this first object outside the solar system would make people think of aliens,” Desch said. “But it’s important in science not to jump to conclusions. It took two or three years to figure out a natural explanation — a chunk of nitrogen ice — that matches everything we know about ‘Oumuamua. That’s not that long in science, and far too soon to say we had exhausted all natural explanations.”

Editors' Recommendations

Georgina Torbet
Georgina is the Digital Trends space writer, covering human space exploration, planetary science, and cosmology. She…
Doorbell camera captures much more than just a house visitor
Google Nest Doorbell (battery) camera lens.

While most Alaskans were tucked up in bed early on Wednesday morning, a number of home security cameras in and around Anchorage captured a natural phenomenon that would otherwise have gone largely unnoticed.

At around 5:45 a.m. local time, a meteor hurtled across the sky, its speed as it hit Earth’s atmosphere causing a bright light that momentarily lit up a large portion of Southcentral Alaska.

Read more
How the ‘hell planet’ covered in lava oceans got so close to its star
An artist’s impression of the planet Janssen (orange circle), which orbits its star so closely that its entire surface is a lava ocean that reaches temperatures of around 2,000 degrees Celsius.

Of the over 5,000 known planets outside our solar system, one of the most dramatic is 55 Cancri e. Affectionately known as the "hell planet," it orbits so close to its star that it reaches temperatures of 3,600 degrees Fahrenheit and its surface is thought to be to covered in an ocean of lava. Located 40 light-years away, the planet has been a source of fascination for its extreme conditions, and recently researchers shared a new theory for how it got so hot.

The planet orbits its star, 55 Cancri A, at a distance of 1.5 million miles which means a year there lasts less than a day here on Earth. “While the Earth completes one orbit around our sun in 365 days, the planet studied here orbits once every 17.5 hours, hugging its host star, 55 Cnc,” said study author Debra Fischer of Yale University in a statement.

Read more
Space Station received special visitors 22 years ago today
The International Space Station.

On this day 22 years ago, three astronauts arrived at the International Space Station (ISS) to begin what's turned out to be a continuous human presence in orbit.

https://twitter.com/Space_Station/status/1587806742225690624

Read more