◎ Science and Technology Daily intern reporter Yu Ziyue reporter Hu Dingkun
According to Israeli media reports, astronomer Loeb of Harvard University of Israeli origin and his research partner Siraj discovered three years ago that the "Manus Island Meteor" that hit the earth in 2014 was an interstellar meteor from outside the solar system, but its data source and accuracy were questioned by peers at the time. Until recently, this research was finally confirmed by the US military.
What a meteor looks like when it falls to Earth. Screenshot source: CNN website
As a result, the "Manus Island Meteor" became the first interstellar visitor to be "intimately in contact" with the Earth discovered by mankind so far, and it was also the third extrasociariate discovered by humans to visit the solar system after the mysterious object "Oumuamua" and the interstellar comet "Borisov", and its visit time was many years earlier than the previous two.
First acquaintance: "Manus Island Meteor" is full of personality
On January 8, 2014, a meteor burning equivalent to 110 tons of TNT explosives dragged a brilliant flame across the sky above the coast of Manus Island in Papua New Guinea and plunged headlong into the depths of the Pacific Ocean.
The fireball that burned above Earth in 2014 was actually rock from another star system. Image credit: Vadim Sadovski
Recently, Siraj published a long article in the journal American Scientific Man describing the detailed process of his and Loeb's study of the meteor, which he called "Manus Island Meteor".
In April 2019, Siraj met the "Manus Island Meteor" in NASA's Near-Earth Object Research Center Database (CNEOS), which is designated "CNEOS 2014-01-08". The database shares data on more than 900 meteors discovered by official U.S. probes since 1988.
At the time, Siraj was an undergraduate student at Harvard University, and Loeb served as his academic mentor. At that time, the interstellar celestial body search boom led by "Oumumo" had not faded, and the relevant data in CNEOS had great potential for mining.
"Meteors of similar size are not uncommon in Earth's skies. Dozens of them appear every year. But what's unusual about this meteor is that it encounters Earth at a very high speed and in an unusual direction, suggesting that it may have come from interstellar space. Within days, Siraj said, he identified the Manus Island Meteor as a potential candidate for an interstellar meteor.
Research: The identity of interstellar meteors is about to be revealed
According to the law of gravitation, objects with relative solar velocities of more than 42 kilometers per second near the Earth's orbit have exceeded the sun's ability to capture, and it is possible to come from outside the solar system.
According to data provided by CNEOS, Siraj calculated that the "Manus Island Meteor" had a speed of nearly 60 kilometers per second, much faster than other meteors, and based on the flight trajectory, it quickly chased from behind the Earth's orbit and crashed into the Earth. If the data is correct, it would be the first interstellar meteor ever discovered to hit Earth. The previously discovered "Oumuamua" and "Borisov" traveled through the solar system in 2017 and 2019, respectively, leaving only a glimpse. In contrast, the "Manus Island Meteor", which was thrown into the arms of the earth in 2014, is obviously more "intimate" with humans.
"Extraordinary claims require extraordinary evidence". In order to make the results more convincing, Buller and Siraj tried to look for evidence to support this conclusion from different angles. The duo used different meteor data from CNEOS and other literature to reverse estimate the measurement error of data on the orbits of related meteors. After a series of tedious and arduous verification work, they came to the same conclusion: even after considering certain errors, the "Manus Island Meteor" apparently came from interstellar space.
Soon, the duo drafted a paper reporting the findings for peer review to publish.
Twists: The source of the rejected data on the paper was questioned
Unfortunately, Bühler and Siraj's paper was rejected. The reason given by the reviewer is that the accuracy of the data cannot be determined.
This brings us to CNEOS, which is the product of a collaboration between the U.S. military and NASA, in which observational data of various meteors are derived from the U.S. military's highly classified spy satellites, which are mainly used to detect ballistic missiles launched by other countries. Therefore, for reasons of confidentiality and other reasons, it does not publish the measurement error range of meteor speed, position, etc. Although Loeb et al. specifically studied the effects of error, their efforts were not recognized by reviewers.
After that, Buller and Siraj found two scientists at los Alamos National Laboratory with advanced security clearances, and through one of them contacted an anonymous analyst with "miraculous powers" who had access to data from U.S. military satellites and confirmed that the measurement error of the "Manus Island Meteor" did not exceed 10%. Based on this margin of error, there is a 99.999% chance that the Manus Island Meteor came from outside the solar system. Again, however, the paper was rejected by reviewers, who argued that the additional corroboration was merely a private exchange with an anonymous U.S. government employee and not an official U.S. government statement.
"After several attempts, which were unable to satisfy the journal reviewers, we regrettably turned to other studies that failed to confirm the true identity of the meteor." Siraj said.
Final Chapter: The U.S. military speaks out to justify its name
The turnaround came a year later.
Pete Warden, president of the Breakthrough Award Foundation who served in NASA and the U.S. military, approached Siraj and introduced Matt Daniels, who was working in the Office of the Secretary of Defense at the time. Daniels read the preprint of the study and was willing to help them get the official statement from the U.S. military.
After another year of multi-layered government bureaucracy, daniels obtained official documents from Lieutenant General John Shaw, deputy commander of the U.S. Space Force, and Dr. Joel Moser, chief scientist of the U.S. Space Operations Command, in March-April 2022, confirming the reliability of the measurements and thus effectively demonstrating the interstellar origin of the Manus Island Meteor.
Three years after the original discovery of Buller and Siraj, the first known interstellar meteor observed by humans from outside the solar system and the first known interstellar meteor have been officially confirmed, and the three-fold identity battle has finally come to an end, and the "Manus Island Comet" has ushered in a real and beautiful finale. At present, Siraj and others are studying whether it is possible to retrieve meteor fragments from the bottom of the Pacific Ocean, and that will be a new story.
Source: Science and Technology Daily
Editor: Zhang Shuang
Review: Julie
Final Judgement: Wang Yu