Mysteriousis likely to go down in the annals of science as the first known interstellar visitor spotted in our solar system, but it's now clear a bit of cosmic rubble that smacked our atmosphere a few years earlier also came from very deep space.
In 2019, two of the Harvard researchers who studied Oumuamua in depth drafted a new paper positing that an extremely speedy meteorite that blazed a trail through the atmosphere in 2014 was also interstellar. The record of its impact and hints at its unusual origin had been hiding in plain sight in a NASA fireball database for years.
"Its high ... speed implies a possible origin from the deep interior of a planetary system or a star in the thick disk of the Milky Way galaxy," reads the summary of the paper from student Amir Siraj and veteran astronomer Avi Loeb.
However, as Siraj recently told Vice, peer review and publication of the paper have been held up because the US military had classified some of the data needed to confirm the scientists' calculations.
That bureaucratic logjam now appears to be broken.
An unusual memo from US Space Command to NASA's science head was shared via the USSC Twitter account last week after deputy commander Lt. Gen. John Shaw revealed its existence at the annual Space Symposium in Colorado.
"Dr. Joel Mozer, the Chief Scientist of Space Operations Command ... reviewed analysis of additional data available to the Department of Defense related to this finding," the memo reads. "Dr. Mozer confirmed that the velocity estimate reported to NASA is sufficiently accurate to indicate an interstellar trajectory."
The meteorite is estimated to have been relatively small, perhaps about the size of a microwave. This means the vast majority of it likely burned up in the atmosphere and any remaining bits fell in the Pacific Ocean.
Still, Siraj is looking into the possibility of searching for any remaining bits on the ocean floor, which Loeb believes could harbor evidence of life from other star systems.
"The reported meteor entered the solar system with a speed of 60 km/s [134,216 mph]," Loeb told me in 2019. "Such a high ejection speed can only be produced in the innermost cores of planetary systems -- interior to the orbit of the Earth around a star like the sun, but in the habitable zone of dwarf stars, hence allowing such objects to carry life from their parent planets."
Since then, Loeb has become something of a controversial figure in science circles for contending that "the simplest explanation" for Oumuamua's origin is that it was created by extraterrestrial intelligence.
It's a hypothesis that will be tough to prove, as Oumuamua is currently speeding away from us in deep space. Similarly, the odds of finding a fleck of meteorite on the ocean floor are about as good as just waiting for E.T. to just show up in person at Harvard.