When ` Oumuamua ( pronounce : oh - MOO - a - MOO - a ) come in our Solar System in 2017 ,   astronomers declare it ourvery first interstellar visitant .

That ’s a pretty telling feat – but was itactuallythe first ?

No . At least , that ’s the argumentation put forth by Harvard prof Avi Loeb and undergraduate student Amir Siraj . In a pre - print report ( awaiting peer - review ) published on the open access astronomy sitearxiv.org , the pair say   ` Oumuamua was go on by another interstellar traveller that flew past Earth on January 6 , 2014 .

" One would await a much gamey copiousness of smaller interstellar objects , with some of them colliding with Earth oft enough to be noticeable , " the researcherswrote .

To try and see out whether or not any of these " small interstellar object " struck past Earth any time recently , the team studied observations sign in the   Center for Near - Earth Object Studies ( CNEOS ) catalogue – a book of the geographic coordinates and geocentric velocity component for excess - sublunary objects detected by US political science sensors .

However ,   in monastic order   to escape the gravitational pull of a wizard and travel from one solar organisation to another , an object has to move incredibly apace . And so , lead author Siraj   and Loeb focused on the very dissolute objects logged .

The one that caught their eyes was a meteor   identified on   January 6 , 2014 , snug to   Manus Island , Papua New Guinea , which " had an outstandingly high-pitched pre - impact heliocentric speed " . The object was just 0.9 meters ( 3 infantry ) widely and was hurtling through the sky at speeds of   216,000 kilometer per 60 minutes ( 134,200 mile per minute ) , suggesting it was unbound to the Sun .

Using computer simulations , the research worker calculated the meteoroid ’s trajectory by tracing its move back in time . They found " no significant " gravitational fundamental interaction between it and another planet until it reached Earth , incriminate it has interstellar origins .

" Its size , trajectory , and excess speed exclude the hypothesis that it was gravitationally scattered within the Solar System prior to bear on , " the researcherswrote .

Siraj and Loeb noted two other   possibly   interstellar object in the data , which covers 30 years ' worth of sightings in amount . Only one of these had an reach that appeared gravitationally bound to the Sun and it was hard to actually affirm the interstellar origins of the second .

Still , they continue , strike that there are   indeed three objective with the electric potential to be interstellar in origin every 30 years , there would be around a million of these objects for every three-dimensional astronomical unit ( the distance between Earth and the Sun , roughly 150 million kilometers/93 million mile ) in the galaxy . Take this further , they say , and it suggest that each nearby star sling 60 billion trillion of these objects during its lifetime .

That sounds like a flock . But asNASApoints out , scientists think interstellar objects like these pass through the Solar System regularly .

The problem is most are too small and too far by to detect .   Oumuamua was olympian not just because of its interstellar origins but because of its size of it , shape and the fact that it was an asteroid and not a comet ( as scientist had presage ) . Scientists calculate something akin to   Oumuamua cut across Earth ’s celestial orbit several of times each twelvemonth . It ’s just that they have been too weak and so too tough to observe .

As for Siraj and Loeb ’s composition , it has been submitted to The Astrophysical Journal Letters but is yet to be peer - go over .

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