Pentagon Says Earth Possibly Hit by Object From Out of Solar System

A space rock that collided with Earth eight years ago could have come from outside of our solar system, a U.S. defense official has said, which would make it one of only two interstellar visitors ever detected.

Earth is surrounded by space rocks. The vast circle of asteroids known as the asteroid belt that sits between Mars and Jupiter is estimated to contain millions of them, and that's not even counting the wayward asteroids that circle the sun in other orbits. Plus, scientists are currently aware of nearly 29,000 individual asteroids that are classed as Near-Earth Asteroids.

All of these objects have one thing in common, though. They live in, and are part of, our own solar system. It is much rarer to find space rocks that are interstellar, meaning they originated from outside of our little nook of the galaxy.

In fact, only one has ever been widely confirmed—the mysterious, cigar-shaped 'Oumuamua, which shot past the sun at 196,000 miles per hour in 2017 and promptly left again.

Meteor burning up
A stock photo depicts a space rock burning up as it flies through the Earth's atmosphere. Asteroids and meteors are common, but objects from outside of the solar system are very rarely detected. ratpack223/Getty

However, it is possible that there was another interstellar visitor before that. In June, 2019, Harvard University astronomers Amir Siraj and Abraham Loeb published a draft report titled Discovery of a Meteor of Interstellar Origin. It described the case of a meteor that burned up in the sky on January 8, 2014.

Based on data collected by NASA's Center for Near Earth Object Studies (CNEOS), the astronomers calculated that the object was travelling at roughly 134,000 miles per hour relative to the sun when it impacted with Earth's atmosphere. This, they said, "implies that the object was unbound." That is, it came from outside the solar system.

Not everyone agreed. Jorge Zuluaga, an astronomer at the University of Antioquia in Colombia, critically analyzed the findings of Siraj and Loeb that same year and noted that "having an unbound trajectory not always means that the object is indeed interstellar."

Now, though, Siraj and Loeb's work appears to have the backing of Joel Mozer, Chief Scientist of Space Operations Command at the United States Space Force.

In a letter posted on Twitter by the U.S. Space Command on on April 7, it is noted that Mozer reviewed the data related to the 2014 meteor.

"Dr. Mozer confirmed that the velocity estimate reported to NASA is sufficiently accurate to indicate an interstellar trajectory," the letter states. It also states that if true, the meteor would "predate the discovery of 'Oumuamua by about 3 years."

This still falls short of absolute confirmation. NASA noted that same day that "the short duration of collected data, less than five seconds, makes it difficult to definitively determine if the object's origin was indeed interstellar."

However, it's a tantalizing suggestion that Earth may be visited by detectable objects from other regions of the galaxy more often than we thought.