The relics of the first interstellar meteor are thought to lie at the bottom of the Pacific Ocean. Last week one controversial scientist and his team claimed to have found them.D
Deep beneath the Pacific Ocean, in an inky abyss roughly a mile (1.6km) underwater, a curious black-and-silver beast is stirring up mud. With a spotted metallic body and wriggling umbilical of purple rope, to the region’s own eccentric deep-sea fauna it might resemble a kind of rectangular stingray. This is the world’s first “interstellar hook” – a unique contraption designed and deployed by the controversial Harvard physicist Avi Loeb. It is on the hunt for alien material – and it may have found something.
Rewind four years, and Loeb was thinking about another strange object: the cigar-shaped comet Oumuamua, which silently slipped past our planet in October 2017, only to disappear forever into the void of space. This was Earth’s first known interstellar visitor – a rogue voyager that may have travelled for some 600,000 years to reach our little blue marble. Loeb’s quest to understand it earned him a new nickname – “The alien hunter of Harvard” – a bestselling book, and no small degree of criticism from fellow scientists.
With this comet in mind, Loeb decided to search for other cosmic anomalies. And this is what led him, via a team of university students and a handy online catalogue of fireballs detected around Earth, to “IM1” – a weird meteorite that exploded over the Pacific Ocean at 3.05am local time on 9 January 2014.
Now Loeb thinks he has found some remnants of this celestial interloper. Could these rare fragments, each around a third of a millimetre across, be debris from a distant Solar System? Has he really managed to sift them out from the vastness of the Pacific? And just why is the search so provocative?
A stark reminder
It’s a startling fact that no human has ever personally encountered material from outside our Solar System – at least, not knowingly.
Despite 66 years of space exploration and hundreds of missions collecting samples from the moon, solar wind, asteroids and low-earth orbit – as well as the more than 70,000 meteorites that have been found on the surface of our planet – the space debris scattered across the world’s museums is all from our own cosmic neighbourhood.
Even the dinosaur-killing imposter that slammed into the Earth 66 million years ago is thought to have come from the Oort cloud, a mass of comets at the farthest edge of our Solar System which regularly throws rocks our way. (Learn more from BBC Future about the mysteries of the Oort cloud.)
“The planetary science community has gathered an amazing body of knowledge about these objects, but we have never been able to study material from another Solar System – the planets and asteroids found around a distant star,” says Marc Fries, cosmic dust curator at Nasa. “We know those systems exist, but have never been able to study them in the laboratory.”
remains a mystery – but it was more robust than steel.
“We found that its material strength must be at least a few times bigger than all other space rocks, 272 of them [at the time] in the same catalogue,” said Loeb, in an interview with the BBC a couple of weeks before the expedition started.
Together with a colleague from Harvard, Loeb calculated with 99.999% confidence that IM1 was an interstellar visitor. This would have made it only the third ever discovered, after the comet 2I/Borisov, which was discovered in August 2019, and Oumuamua – only this time, it had ended up within reach. But there was a catch.
When the team wrote up their findings, the paper was initially rejected for publication in a scientific journal, partly because the experts reviewing it felt they needed more detail. In need of urgent access to classified documents, Loeb’s mission stalled.
study on unidentified anomalous phenomena (UAPs), agrees that IM1 was an intriguing object – though he says this doesn’t mean it was made by intelligent extraterrestrials.
“It will tell us something about how planet formation proceeds,” says Spergel, who does, however, believe that it is most likely a rock from outside our own Solar System. ”So, you know, I think this is an example of an interesting study and that Avi was motivated to study a region of parameter space that people hadn’t looked at. I don’t see any reason to think that this represents an alien technology, as opposed to, you know, an asteroid that hit the Earth,” he says.
There is only one way to find out.
The interstellar hook is designed to slide along the seafloor, fishing out any magnetic particles in its path (Credit: Abraham Loeb)
A daring search
Loeb’s meteor search team arrived onboard the Silver Star on 14 June, and soon arrived at a patch of velvety-blue ocean around 84km (52 miles) from the tropical shores of Manus Island, Papua New Guinea. This is where, using a combination of US military data and local seismology readings, Loeb calculates the debris from the meteorite will have landed.
Armed with their “interstellar hook” and more than $1m (£786,000) in backing from the founder of the blockchain company Cardano, the team began the journey by collecting control samples from outside their search area, which is being used for comparison with debris from IM1. The hook is designed like an underwater sled and is towed behind the ship from a long rope. It can either pick up samples of potential meteor debris using the spots on its surface, which are powerful magnets, or with less discerning collection nets.
This is crucial, because what Loeb and his team have been hoping for – other than a large chunk of debris – are spherules. These tiny spheres of metal or glass, often roughly 1mm across, are formed in the incandescent blaze as meteorites or asteroids explode, and have been found at impact sites all over the world.
Last year, scientists at Tanis, a fossil site in North Dakota where it’s thought many dinosaurs and other animals were entombed on the day of the fateful era-ending asteroid strike, announced that they had found similar tiny clues inside fossilised fish. The spherules were still in the creatures’ gills, where they were breathed in 66 million years ago.
Though almost a decade has passed since debris from the meteor rained down over the Pacific Ocean, Loeb is confident that at least some of these spherules will still be lurking close to the surface of the seabed. And if IM1 contained a magnetic material such as iron – which is commonly found in meteorites – the plan was that some of these tiny particles might be picked up.
scientist may propose any hypothesis, and any other scientist may test that hypothesis… everyone learns something new and progress is made towards the truth of the issue…We shall see how that proceeds in this particular case.”
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