Solar System’s first-known interstellar visitor was a chunk of a ‘Pluto-like planet,’ scientists say

‘Oumuamua probably originated in another star system, astronomers posit.
Mauna Kea Observatory, Big Island, Hawaii
Mauna Kea Observatory, Big Island, Hawaii
(Michael Orso/Getty)

The first interstellar object detected in our Solar System likely came from a small planetoid in another star system, scientists announced in findings this week. 
‘Oumuamua made headlines in 2017 as it zipped near the Sun when scientists determined that it was very likely to have originated from another planetary system elsewhere in the galaxy. 

There are possibly hundreds of millions, if not tens of billions, of solar systems in the Milky Way galaxy; the nearest to ours, Alpha Centauri, is roughly 25 trillion miles away from Earth. 

‘Oumuamua’s origins are at present not known. But scientists at Arizona State University this week said that the flat, round object was “likely knocked off the surface [of a small planetoid] by an impact about half a billion years ago and thrown out of its parent system.”

The object, estimated to be at max 3,000 feet long, “likely wasn’t flat when it entered our solar system,” Arizona State said in its press release; rather, it likely “melted away” as it came close to the sun. 

The conclusions reached by the Arizona State scientists suggest that planetoids similar to Pluto’s may be prevalent in the rest of the Milky Way. 

“Until now, we’ve had no way to know if other solar systems have Pluto-like planets,” Arizona State astrophysicist Steven Desch said, “but now we have seen a chunk of one pass by Earth.”