The mysterious interstellar object ‘Oumuamua was a chunk of planet from another solar system, a new study says

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An artist’s impression shows interstellar object `Oumuamua as it passed through the solar system in October 2017.

The origin and identity of a massive space object that careened past Earth in 2017 have remained a mystery ever since.

The object, called ‘Oumuamua – a Hawaiian name meaning “scout” or “messenger” – traveled on a trajectory that strongly suggested it came from another star system. That made it the first interstellar object ever detected.

But what was it? A few researchers, including Harvard University astronomer Avi Loeb, posited the object was an alien spacecraft. Others suggested it was an asteroid, or perhaps an interstellar comet.

Now, a pair of papers published in an American Geophysical Union journal offers another theory: that ‘Oumuamua was shrapnel from a tiny planet in a different solar system.

“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,” Steven Desch, an astrophysicist at Arizona State University and a co-author of the new study, said in a press release.

A planetary fragment made of frozen nitrogen

Desch and his coauthors think that half a billion years ago, a space object struck ‘Oumuamua’s parent planet. That sent ‘Oumuamua careening towards our solar system.

Once it neared the sun, their thinking goes, ‘Oumuamua sped up as sunlight vaporized its icy body. Comets follow a similar movement pattern, known as the “rocket effect.”

Because ‘Oumuamua’s makeup is unknown, the researchers calculated what kinds of ice would sublimate (change from solid to gas) at a rate that could account for ‘Oumuamua’s rocket effect. They concluded that the object is likely made of nitrogen ice, like the surface of Pluto and Pluto’s moon Triton.

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An enhanced-color view of Pluto, taken by NASA’s New Horizons spacecraft.

As it got approached our solar system – and therefore the sun – ‘Oumuamua started sloughing off frozen nitrogen layers. The object entered our solar system in 1995, though we didn’t realize it at the time, then subsequently lost 95% of its mass and melted away to a sliver, according to the study authors.

It’s a comet. It’s an asteroid. Nope, it’s neither.

oumuamua 1I 2017 u1 solar system trajectory illustration comet asteroid or alien spaceship nasa swri esa stsci PIA22357_fig1
An illustration of the space object ‘Oumuamua flying through the solar system in late 2017.

By the time astronomers became aware of ‘Oumuamua’s existence in 2017, it was already zipping away from Earth at 196,000 mph. So they had only a few weeks to study the strange, skyscraper-sized object. Several telescopes on the ground and one in space took limited observations as the object flew away, but astronomers were unable to examine it in full. ‘Oumuamua is now too far away and too dim to observe further with existing technologies.

The limited nature of the information gathered left room for scientists to offer guesses about what the object might be and where it came from. ‘Oumuamua was initially classified as a comet, but it didn’t appear to be made of ice, and it didn’t emit gases as a comet would.

‘Oumuamua’s spin, speed, and trajectory couldn’t be explained by gravity alone, which suggested it was not an asteroid either. And the object’s shape and profile – it’s about one-quarter of a mile long but only 114 feet wide – doesn’t match that of any comet or asteroid observed before.

According to the authors of the new study, however, ‘Oumuamua’s frozen-nitrogen composition could explain that shape.

“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,” Alan Jackson, another study co-author, said in the release.

Some astronomers still think it was an alien ship

Unlike most space rocks, ‘Oumuamua seemed to be accelerating, rather than slowing down, in telescope observations.

That is in part why Loeb thinks ‘Oumuamua was an alien spacecraft. In a book he published in January, titled “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth,” Loeb describes ‘Oumuamua as a defunct piece of alien technology.

“The object has anomalies that merit some attention – things that do not line up in the ways we expected,” he told Insider in December. “Other people say, ‘Lets shove those anomalies under the rug of conservatism.’ I have a problem with that because when something doesn’t line up, you should say it.”

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An artist’s depiction of ‘Oumuamua.

Still, a 2019 study from an international group of astronomers analyzed all the ‘Oumuamua data available and concluded that Loeb’s theory was unlikely.

“We find no compelling evidence to favor an alien explanation for ‘Oumuamua,” the astronomers wrote.

Matthew Knight, a University of Maryland astronomer who co-wrote the study, put it this way: “This thing is weird and admittedly hard to explain, but that doesn’t exclude other natural phenomena that could explain it.”

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China’s new Mars probe took its first photo of the red planet as the mission prepares to make history

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A black-and-white image of Mars taken by China’s Tianwen-1 probe, released by China on February 5, 2021.

China’s first interplanetary probe is now so close to Mars that its camera can make out craters across the red planet’s surface.

The Tianwen-1 spacecraft, a suite of robots launched by the China National Space Administration (CNSA) in July, has spent the last six months speeding through space. At just 2.2 million kilometers (1.4 million miles) from its destination, the probe beamed back its very first photo: a black-and-white snapshot of Mars.

The CNSA released the picture on Friday. In a press release, the agency said that the probe had fired an engine as part of its fourth “orbital correction,” or adjustment of its path through space. Now Martian gravity should pull the mission into just the right orbit around the planet.

The five-ton probe is set to carry out a braking operation to slow its high-speed spaceflight and slip into orbit around Mars on February 10. Following that, the spacecraft will spend a couple months surveying a landing site at Utopia Planitia, a vast field of ancient volcanic rock.

The orbiter is supposed to drop a lander-rover combo to the planet’s surface in May, the CNSA said. If the rocket-powered descent goes smoothly, the lander will deploy a two-track ramp  for the rover to roll onto Martian soil. The rover’s radar system will help Chinese researchers seek out underground pockets of liquid water. (The orbiter, meanwhile, will continue circling the red planet and relaying data to Earth.)

Such ancient water reservoirs could be remnants of a time billions of years ago when Mars flowed with rivers, courtesy of a much thicker and protective atmosphere than exists today. During this era, Mars somewhat resembled Earth, and scientists think it may have hosted alien microbial life. Any underground pockets of water, shielded from the sun’s unfiltered radiation and the vacuum of space, might still harbor such species, if they exist.

If successful, Tianwen-1 will be the first Mars mission to send a spacecraft into orbit, drop a landing platform, and deploy a rover all in one expedition. It will also mark China’s first landing on another planet and help the nation prepare a future mission that might return a Martian rock or dirt sample to Earth in the late 2020s.

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An illustration of China’s planned Mars Global Remote Sensing Orbiter and Small Rover mission, or HX-1. Here a rover is shown leaving a lander to explore the Martian surface.

As of Friday, the CNSA said Tianwen-1 is just about 1.1 million kilometers (680,000 miles) from its destination.

Two other missions which launched around the same time as Tianwen-1 – NASA’s Perseverance rover and the United Arab Emirates’ Hope probe – are also arriving at Mars in the next two weeks. All three missions are taking advantage of a window when Mars passes close to Earth, decreasing travel time and cost.

China attempted to send an orbiter to Mars in 2011, but the Russian spacecraft that was meant to carry it there stalled in Earth’s orbit and never left.

Tianwen-1 is the closest China has ever gotten to another planet. With luck – and the right engineering to weather a harrowing “seven minutes of terror” as it plunges toward Mars – it will reach the surface.

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A Harvard professor has claimed in his new book that alien debris passed near Earth in 2017. It has attracted both skepticism and intrigue.

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This artist’s impression shows the first-known interstellar object to visit the solar system, “Oumuamua,” which was discovered on October 19, 2017, by the Pan-STARRS1 telescope in Hawaii.

  • Scientists in 2017 detected the first sign of intelligent life outside Earth, according to a new book by Avi Loeb, a Harvard University professor. 
  • The “rocky, cigar-shaped object with a somewhat reddish hue,” was called “1I/2017 U1 ‘Oumuamua” by NASA.
  • “There was only one conceivable explanation: the object was a piece of advanced technology created by a distant alien civilization,” according to publisher Houghton Mifflin Harcourt.
  • Visit Business Insider’s homepage for more stories.

An extraterrestrial object skimmed through space close to Earth in 2017, wrote a Harvard University astronomer, Avi Loeb, in a book to be published this month. 

It was the first sign of intelligent life outside Earth, according to Loeb. 

Scientists at a Hawaiian observatory saw “an object soaring through our inner solar system, moving so quickly that it could only have been from another star,” according to the marketing summary for the Houghton Mifflin Harcourt book, “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth.”

The object wasn’t a natural occurrence, but a bit of space junk ejected by another galaxy, according to Loeb, a professor of science with a doctorate in physics. 

“There was only one conceivable explanation: the object was a piece of advanced technology created by a distant alien civilization,” according to HMH. 

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Physicist Avi Loeb, right, on stage with physicist Stephen Hawking and others.

In a review, Publishers Weekly called the book a “contentious manifesto.” 

But Loeb wasn’t alone in his excitement about the object, which was called “1I/2017 U1 ‘Oumuamua” by Nasa.

“The first confirmed object from another star to visit our solar system, this interstellar interloper appears to be a rocky, cigar-shaped object with a somewhat reddish hue,” NASA said in its description of the object. 

“For decades we’ve theorized that such interstellar objects are out there, and now – for the first time – we have direct evidence they exist,” said Thomas Zurbuchen, associate administrator for NASA’s Science Mission Directorate in Washington, when it was originally discovered. 

He added: “This history-making discovery is opening a new window to study formation of solar systems beyond our own.” 

In the book-jacket blurb, Anne Wojcicki, CEO and cofounder of 23andMe, wrote that Loeb’s new book “convinces you that scientific curiosity is key to our future success.”

“An exciting and eloquent case that we might have seen a sign of intelligent life near Earth – and that we should search further,” she wrote. 

Fellow Harvard professor Eric Maskin, a Nobel laureate in Economics, added: “Is the hypothesis right? Who knows. But let’s try to find out!”

 

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