The US Space Force (USSC) has published a declassified document examining an object that swept across the sky over Papua New Guinea in 2014. Scientists concluded that it was a meteorite from another star system.
The small meteorite, only 0.45m in diameter, entered Earth's atmosphere on 8 January 2014 at over 210,000km/h, well above the average speed of meteorites within the solar system, according to a paper published in 2019 in the arXiv preprint database. Scientists claim that the speed and trajectory of the tiny meteorite prove with 99% accuracy that it originated far from outside our solar system. It may have come to us 'from the bowels of a planetary or stellar system somewhere deep in the Milky Way galaxy', the authors write.
Despite their near certainty of their conclusions, the paper has so far not been published in scientific journals because some of the data used in it has been classified by the US government. The USSC has now officially confirmed the group's views. In a March 1 memorandum, Lieutenant General John Shaw, deputy commander of the USSC, wrote that the analysis of the 2019 meteorite was "accurate enough to confirm its interstellar trajectory".
This confirmation makes the 2014 meteorite the first interstellar object to pass through the solar system. Asteroid 1I/Oumuamua, spotted in 2017, was previously thought to be such an object.
Amir Siraj, a theoretical astrophysicist at Harvard University and lead author of the 2019 paper, told Vice that he still intends to publish his paper so that the scientific community can continue researching the meteorite from where he and his colleagues left off. He added that since the meteorite was spotted over the South Pacific, it is possible that its fragments fell into the water and have been lying on the seabed ever since.
While finding these pieces of interstellar debris could be an almost impossible task, Siraj said he was already consulting with experts about the possibility of organising an expedition to look for them.
"The possibility of getting the first piece of interstellar material is interesting enough to test it thoroughly and invite the cooperation of all the world's experts on ocean expeditions to search for meteorites," concluded Siraj.