In early 2014, a dishwasher-sized meteor crashed off the coasts of Papua New Guinea before sunrise as it burned up in the scorching friction of the Earth’s atmosphere. But two Harvard scientists claimed that this was not just any space rock: it originated from a different star system, they said, making it the first observed meteor of interstellar origin.
They wrote 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 allegation of the fireball in the published data, which came from a NASA database and relied on readings that were blurred 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 admitted, it was difficult “to find out if the object was really interstellar or not.”
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But it turned out that the truth was out there. Last month, the U.S. Space Command released a note to NASA scientists saying the data from the missile warning satellites’ sensors “were accurate enough to indicate an interstellar orbit” for the meteor. The release of the note was the culmination of a three-year effort by Siraj and a well-known Harvard astronomer, Avi Loeb.
Many scientists, including those at NASA, say the military has still not released enough data to confirm the interstellar origin of the space rock, and a spokesman said the Space Command would leave the matter to other authorities. But it was not the only information about meteors that was released. The military also released NASA decades of secret military data on the brightness of hundreds of other fireballs or bolides.
“It’s an unusual degree of visibility of a set of data coming from that world,” said Matt Daniels, assistant director of space security at the White House Office of Science and Technology Policy, who worked on the data release. “We are in this renewed period of excitement and activity in space programs in general, and in the midst of it, I think thoughtful leaders in several places said, ‘you know, now is a good time to do this.'”
In recent years, a few objects that passed through our immediate star quarter have attracted considerable attention because it was confirmed that they originated outside the solar system. The first object was Oumuamua, a long, flat body that zoomed through the solar system in 2017. Loeb, one of the two who studied the 2014 meteorite, has also attracted attention and disagreement by claiming that Oumuamua was technology sent of intelligent life. Other astronomers are still debating what kind of natural object it was.
In 2019, Borisov, one comet about the size of the Eiffel Tower, became the second confirmed interstellar visitor. A piece of it broke off in 2020 after it rounded the sun.
While data from classified military satellites may not have helped the study of these interstellar visitors, they could help academic researchers study objects closer to Earth. They could also help NASA in its federally assigned role of defending planet Earth from lethal asteroids. And that’s the goal of a new agreement with the US Space Force, which aims to help NASA’s Planetary Defense Coordination Office better understand what happens when space rocks reach the atmosphere.
Daniels played a key role in the efforts of Harvard scientists to obtain a public opinion from the Space Command. After being rejected by The Astrophysical Journal Letters, a peer-reviewed scientific publication, Loeb said he contacted a colleague at the Los Alamos National Lab, who eventually linked him to Daniels. Daniels then brought the meteor up in a conversation with Space Command officials in 2020, which kickstarted the government’s efforts to make a public statement about the military satellite’s data on the alleged interstellar meteor.
“I knew this was going to be a challenge, and so it was an ongoing conversation for some time,” Daniels said.
Sharing sensitive military satellite data with astronomers has led to significant scientific discoveries in the past.
A group of satellites deployed in the 1960s by the United States to detect secret detonations of nuclear weapons on Earth accidentally became the key instruments used to make the first detection of extraterrestrial gamma-ray bursts. The eruptions appeared on the satellites, codenamed Vela, as individual energy eruptions, which confused analysts at Los Alamos, who later declassified the data in a 1973 paper that spurred academic debate on the origin of the eruption.
But while arguments about the gamma-ray bursts were largely resolved later, Siraj and Loeb’s hypothesis about the interstellar meteor is still the subject of disagreement.
While many – including the two Harvard astronomers – have interpreted the Space Command’s statement to NASA as a confirmation that the meteor is interstellar, some astronomers believe more data is needed to support the claim. The available measurements, they say, lack error bars indicating how accurate or uncertain they were.
‘The sentence is not enough. Scientific results are published; they are not secret, ”said Maria Hajdukova, a researcher at the Astronomical Institute of the Slovak Academy of Sciences in Slovakia, who is studying meteors and examining the confirmation of the space command. “I’m not saying I do not believe it, but if I do not have the facts, I can not claim it,” she added.
NASA said in a public statement this month that “the short duration of data collected, less than five seconds, makes it difficult to definitively determine whether the object’s origin was actually interstellar.”
“Honestly, we can not confirm that it is interstellar,” said NASA’s planetary defense officer, Lindley Johnson. “Although it is of high speed, a speed that could potentially be interstellar, it is almost impossible to confirm that it is interstellar without accompanying data – from a longer data span or data from other sources that do not exist in this case.”
Loeb and Siraj disagreed. “Five seconds is a lot of time,” Loeb said. “It’s not the duration that matters, it’s the quality of the data that was collected that matters. In five seconds you can do a lot in terms of instrumentation and measurement.”
He and Siraj plan to resubmit their paper to The Astrophysical Journal Letters. And the data on the 2014 meteor, now coming from the military agency, could help their argument, said Peter Veres, an astronomer at the International Astronomical Union’s Minor Planet Center, which tracks objects in the solar system.
These data show an unusual sequence of three light explosions as the object ran through the Earth’s atmosphere. “It looks strange, I can tell you that,” Veres said, noting that the brightness of meteors during their dives typically only peaks once.
The Space Command letter was provocative enough to be noticed by NASA officials, who shared it throughout the agency’s Science Mission Directorate and with its Small Bodies Assessment Group. Lori Glaze, director of NASA’s planetary science department, said in an email to colleagues that “we believe the potential of this event, which is a particularly high-speed entry of a very small body into Earth’s atmosphere, will be off interest in the community with small bodies. ”
A key reason for the Space Force’s growing ties to NASA has centered on the agency’s congressional mandate to detect almost any asteroid that could threaten Earth. When NASA signed an agreement in 2020 to strengthen ties with the Space Force, the agency acknowledged that it had lagged behind in its asteroid tracking efforts and would need Pentagon resources to carry out its planetary defense mission.
The recent bolide agreement, which gives NASA access to light curve data that will help scientists analyze the physical properties of crashing fireballs, is a step in that direction.
“This is a very rich dataset that has now been released by the US Space Force and the US Space Command for the scientific community,” Johnson said. “I know the meteorologists, those who now have a chance to look at this data and compare it to other data sources and such, are very excited about it.”
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