The US Space Command has confirmed the findings of Harvard scientists that a space rock from another star system struck Earth in 2014.
The announcement pushes back the date of the first confirmed discovery of an extrasolar visitor by three years, raises the possibility, however remote, of collecting fragments of the alien meteorite from the Pacific ocean where it exploded in a fireball, and suggests that extrasolar space rocks may be common visitors to our Solar system.
On 6 April, Space Command issued a memo confirming the work of Harvard astronomers Amir Siraj and Abraham Loeb, noting that the velocity and trajectory of the meteor suggested the space rock was extrasolar in origin. Drs Siraj and Loeb wrote a paper in 2019 making the case for an extrasolar origin for the meteor and posted it to the scientific preprint server ArXiv. But the pair have been unable to get the paper published in a peer reviewed journal due to its reliance on data from some sensors used by the US Department of Defense, according to reporting by Vice.
6/ “I had the pleasure of signing a memo with @ussfspoc’s Chief Scientist, Dr. Mozer, to confirm that a previously-detected interstellar object was indeed an interstellar object, a confirmation that assisted the broader astronomical community.” pic.twitter.com/PGlIOnCSrW
— U.S. Space Command (@US_SpaceCom) April 7, 2022
In the wake of the discovery of Oumuamua, a large, elongated asteroid passing through our Solar System and ultimately determined to be of interstellar origin, Loeb and Siraj began looking through historical data from Nasa’s Center for Near Earth Object Studies (CNEOS) for evidence of small meteors that could also have come from outside the Solar System and burned up in the Earth’s atmosphere. One of these meteors generated a fireball detected near Papua New Guinea on 8 January 2014, and the CNEOS data indicated it came from a small meteor that was traveling unusually fast with respect to the Sun, an indication it originated from outside the Solar System.
When they crunched the numbers, Drs Loeb and Siraj concluded “with 99.999% confidence that the 2014-01-08 meteor was interstellar,” but the margin of error wasn’t good enough to get their paper through the peer review process. That, Vice reported, would require data from CNEOS sensors that the US military also uses to monitor for the fireballs created by nuclear weapons.
The 1 March Space Command memo, signed by Joel Mozer, the chief scientist of US Space Operations Command, may help get the paper out of publishing limbo.
And publication aside, the memo confirms that Oumuamua was not the first interstellar visitor to the Solar system, and suggests neither it nor the 2014 meteor will be the last: In the paper, Drs Sirah and Loeb calculate that Earth is struck by an extrasolar meteor around once a decade, with more than 450 million such meteors striking Earth over its lifespan so far.
It’s even possible, they wrote in the paper, that such interstellar emissaries could carry evidence of alien life. “Potentially, interstellar meteors could deliver life from another planetary system and mediate panspermia.”
Dr Loeb has also argued that Oumuamua could have been a form of Alien technology, rather than an extrasolar asteroid, but this is a minority position among the astronomy community.
Signs of life of not, Dr Siraj told Vice he would like to organise an expedition to see if any fragments of the 2014 meteorite could be recovered from the Ocean.
“It would be a big undertaking,” he said, “but we’re going to look at it in extreme depth because the possibility of getting the first piece of interstellar material is exciting enough to check this very thoroughly.”