In early 2014, a dishwasher-size meteor dashed over the shores of Papua New Guinea before sunrise as it burned up in the fiery friction of Earth’s atmosphere. But two Harvard researchers argued that this wasn’t just any space rock: It originated from another star system, they said, making it the first observed meteor of interstellar origin.
They wrote up the extraordinary claim and submitted it to an astronomy journal. But the paper was not accepted for publication. Reviewers noted a lack of sufficient detail to verify the claim about the fireball in the published data, which came from a NASA database and relied on readings that were obscured because they were from U.S. intelligence community satellites, and could reveal how the military monitors missile launches.
“We had thought this was a lost cause,” said one of the researchers, Amir Siraj,a Harvard undergraduate student studying astrophysics. Without the more thorough data, he conceded, it was difficult “to figure out whether the object was truly interstellar or not.”
But, it turned out, the truth was out there. Last month, the U.S. Space Command released a memo to NASA scientists that stated the data from the missile warning satellites’ sensors “was sufficiently accurate to indicate an interstellar trajectory” for the meteor. The publication of the memo was the culmination of a three-year effort by Mr. Siraj and a well-known Harvard astronomer, Avi Loeb.