Researchers identified the first known interstellar meteor that hit Earth some 8 years ago, CNN reported detailing new developments in the discovery of recent years.
It is indeed an uncommon occurrence in our solar system, since an interstellar meteor is a space rock that originates from beyond our solar system.
According to the report, Amir Siraj, who recognized the item as an interstellar meteor in a 2019 article he co-authored as an undergraduate at Harvard University, was taken aback by the discovery. Siraj was working with Harvard University professor of science Abraham Loeb on a study of 'Oumuamua, the first known interstellar object discovered in our solar system in 2017.
Then, the student proceeded to search NASA's Center for Near Earth Object Studies (CNEOS) database for other interstellar objects, to discover what he thought was an interstellar meteor.
"Since there should be a higher abundance of interstellar objects smaller than ‘Oumuamua, we could observe small interstellar objects impacting the Earth’s atmosphere," the study reads.
Citing the data obtained from the CNEOS, Siraj noticed the high velocity the meteor had before it had collided with our planet in 2014. The meteor was traveling at a high rate of roughly 45 kilometers per second in comparison to Earth, which is traveling around the sun at around 30 kilometers per second, according to the study. The 45 kilometers per second was not the real speed of the meteor because experts recorded it while traveling on a moving planet.
In its turn, the heliocentric speed, which is a more accurate technique of determining an object's orbit, is defined as the meteor's speed relative to the sun. It's determined by the angle at which a meteor collides with the Earth.
The planet revolves around the sun in one direction, therefore the meteor might have struck Earth either head-on, in the opposite direction as the planet, or from behind, in the same direction as the Earth.
And the researcher calculated that the meteor was moving at around 60 kilometers per second relative to the sun since it hit Earth from behind. Then, they calculated the meteor's course and discovered that it was in an unbound orbit, as opposed to the closed orbits of typical meteors.
This suggested that the meteor, CNEOS 2014-01-08, came from beyond the solar system, rather than circling the sun like other meteors.
"Presumably, it was produced by another star, got kicked out of that star's planetary system and just so happened to make its way to our solar system and collide with Earth," Siraj said, per CNN.
Because their data originated from NASA's CNEOS database, which reportedly does not reveal details like how reliable the readings are, Loeb and Siraj have been unable to get their findings published in a peer-reviewed journal.
According to the report, after years of attempting to collect the necessary information, they gained official confirmation from John Shaw, deputy commander of the US Space Command, that it was, in fact, an interstellar meteor.
"I thought that we would never learn the true nature of this meteor, that it was just blocked somewhere in the government after our many tries, and so actually seeing that letter from the Department of Defense with my eyes was a really incredible moment," Siraj told the outlet.
The astronomer reportedly said his team is preparing to resubmit their findings for publication in a scientific journal after receiving confirmation.
The mentioned meteor, about 0.45m in size, if confirmed, will join 1I/2017 U1 ('Oumuamua) and 2I/Borisov as the third interstellar object detected.