Was it an asteroid, a comet, or even an alien spacecraft? Since 2017 and the appearance of a mysterious object from another star system in our system, the solar system, astrophysicists have not known what to make of Oumuamua. It was the first object of this kind that visited us. The interstellar visitor, which was about 100 meters wide and 400 meters long, was also notable for its brilliance and a wide variation in brightness, giving the impression of a spinning metallic object. Also, it looked like an asteroid but behaved like a comet.
But even stranger, after orbiting the sun, ‘Oumuamua accelerated and went off course, propelled by a mysterious force that ejected it from the solar system.
A Boy Scout”
Discovered by a telescope in Hawaii, the object “Oumuamua” — which means “scout” in Hawaiian — has caused a stir in the astronomical community, which has long been searching for comet-like objects entering our solar system from the far reaches of space.
So many curiosities that even a famous astronomer had seen an alien ship there. We’ve known since 2019 that its origins are very natural, thanks to an analysis by the University of Maryland’s Astronomy Department. But what about the rest?
The scientists were stunned, and ended up with four months of incomplete and seemingly conflicting data they were trying to figure out. A whole series of theories arose from this.
Some “Inconceivably”, underlines with AFP Jennifer Bergner, astrochemist at the University of California at Berkeley, co-author of the study published in Nature.
Trapped Hydrogen
According to his explanation, regardless of its origin, Oumuamua is a water-rich, comet-like object. During its journey through interstellar space, it was exposed to cosmic rays that bombarded the water and released hydrogen, which became trapped in the object’s body.
As the bolide approached the sun, the heat in turn released the trapped hydrogen and acted as an “engine” that sent it on an unexpected course. “Trapped hydrogen is simply the most general explanation,” explains Darryl Seligman from Cornell University and co-author of the study in a press release.
These jobs “provide undoubtedly the first simple and realistic explanation of the peculiarities of this object”, commented Marco Micheli, astronomer at the European Space Agency (ESA).
Persistent differences among scientists
But not everyone agrees with these conclusions. Starting with Avi Loeb, former director of Harvard University’s astronomy department: the eminent scientist had argued that the most believable scenario is that ‘Oumuamua is an extraterrestrial ship. A controversial thesis he defended in a 2021 book entitled The first sign of extraterrestrial intelligent life.
Asked by AFP about studying nature, the astrophysicist confirms that saying a comet has no tail “It’s like saying an elephant is a zebra without stripes.” He recalls that Comet 2I/Borisov, the second visitor from outside the solar system discovered in 2019, had a long dusty hair.
Answer from Jennifer Bergner: If Oumuamua is tailless, it’s probably because it’s much smaller than any comet observed so far – including 2I/Borisov.
“A convincing non-alien explanation”
The situation could change soon. Observations from the Vera C. Rubin Telescope in Chile, scheduled to begin in 2025, are expected to discover many new comets both inside and outside the solar system. If the smaller signs show them releasing trapped hydrogen and lacking a tail, like Oumuamua, that would confirm the theory, the astrochemist added.
As for the possibility of extraterrestrial intelligent life, “It all depends on the level of evidence required” to conjure it up, the scientist comments.
“We’ll never know exactly what Oumuamua was – we missed our chance. But for now, I think we’re providing a compelling non-alien explanation.” closes them.