The visit to the strange interstellar object Oumuamua has an explanation
The Oumuamua interstellar object.
The passage of a mysterious fireball through our solar system in 2017 had astrophysicists baffled, with one going so far as to see alien technology. A study published Wednesday offers a “non-alien” explanation for this exotic visit.
Spotted by a telescope in Hawaii, Oumuamua – which means scout in Hawaiian – was speeding so fast that it could only come from, and for the first time, another star system. /p>
This discovery has the astronomical community in turmoil, who have long searched for comet-like objects entering our solar system from the vastness of space.
Except that Oumuamua did not look like the usual comets: it did not have this characteristic hair that their immense halo of gas and dust forms when approaching the Sun.
This interstellar visitor, which was about 100 meters wide, was also distinguished by its brilliance and a large variation in brightness, which gave the impression of a metallic object turning on itself- same.
Stranger still, however, after circling the Sun, Oumuamua accelerated and veered off course, propelled by a mysterious force that ejected it from the solar system.
Scientists were left stunned, ending up with four months of incomplete and seemingly contradictory data that they tried to figure out, which gave rise to a whole host of theories.
Some were beyond imagination, underlines with AFP Jennifer Bergner, astrochemist at the University of California at Berkeley and co-author of the study published in Nature (in English).
According to his explanation, whatever the origin of Oumuamua, it is about ;a water-rich, comet-like object. During its journey through interstellar space, it was subjected to cosmic rays which bombarded the water releasing hydrogen, which became trapped in the body of the star. #x27;object.
As the fireball approached the Sun, the heat in turn released the trapped hydrogen, acting as a propellant that sent it on an unexpected path.
Trapped hydrogen is simply the most generic explanation, Darryl Seligman of Cornell University, also co-author of the study, said in a statement.
This work undoubtedly provides the first simple and realistic explanation of the particularities of this object, commented Marco Micheli, astronomer at the European Space Agency (ESA).
But these conclusions do not make everyone agree. Starting with Avi Loeb, former head of the astronomy department at Harvard University: the eminent scientist had argued that the most believable scenario was that Oumuamua was an alien craft.< /p>
A controversial thesis, which he defended in 2021 in a book entitled The first sign of extraterrestrial intelligent life.
Asked by AFP about Nature study , the astrophysicist claims that saying a comet has no tail is like saying an elephant is a zebra without stripes. He recalls that comet 2I/Borisov, the second outside visitor to the solar system spotted in 2019, had a long hair of dust.
Response from Jennifer Bergner: If 'Oumuamua lacks a tail, it's probably because it's much smaller than all comets observed so far, including 2I/Borisov.
< p class="e-p">The situation could soon change. Observations from the Vera-C.-Rubin telescope in Chile, which will begin in 2025, are expected to detect many new comets both inside and outside the solar system. If the smaller ones show signs of releasing the trapped hydrogen and don't have a tail, like Oumuamua, that would confirm the theory, the astrochemist added.
As for the possibility of intelligent, extraterrestrial life, it all depends on the level of proof required to invoke it, comments the scientist.
We don't we will never know for sure what Oumuamua was: we missed our chance. But for now, I think we provide a compelling non-alien explanation, she concludes.
