By akademiotoelektronik, 04/04/2022
Has an alien vehicle skimmed past Earth? | The Press
An alien craft visited Earth in late 2017, according to a new book published by Harvard University astrophysicist Avi Loeb. In Extraterrestrial, he argues that the appearance and trajectory of Oumuamua, the first asteroid to originate outside our solar system, cannot be explained by plausible natural phenomena. A theory that is not unanimous. Interview.
When did you start thinking Oumuamua was a spaceship?
There were abnormalities in terms of reflexivity. But the trigger was made when we saw an inexplicable change in the exit trajectory of the Solar System.
It was propelled by a solar sail, according to your explanations. Why ?
It is a technology which makes it possible to reach very high speeds, and to pass from one solar system to another in just a few decades. We use the photon energy of a star to accelerate, and it increases all the time.
Critics have offered some natural explanations for Oumuamua's change in trajectory.
There are two major assumptions. Either Oumuamua is a block of pure hydrogen, or it is a very diffuse cluster — 100 times less dense than the air on our planet — of ice particles. In either case, it is difficult to understand how such an object could have been created, and also how it could have survived for decades, or centuries, without melting in the case of hydrogen or dissipating into the second case. Other reviews cite another interstellar object (2I/Borisov) that looks a lot like a comet. I find that the banality of this second interstellar object underlines the exceptional character of Oumuamua.
> Watch an animation of Oumuamua's trajectory in 2017
You are criticized for not being a specialist in comets and asteroids.
It's true. A journalist called me a "child terrible of astronomy", a nickname that does not please me. But I think we can have a reasonable discussion between scientists without denigrating anyone who makes extraordinary assumptions. The natural explanations in the case of Oumuamua are equally extraordinary.
You propose to prepare a mission to explore other objects from outside the Solar System.
With the telescope of the Vera-C.-Rubin Observatory, which will be completed within four years in Chile, we will be able to detect such objects when they approach the Earth, instead of seeing them at the last minute and not being able to react. By strategically placing small satellites equipped with inexpensive cameras in Earth's orbit around the Sun, they can be photographed. I'm surprised to be criticized for this project, because if it's exceptional natural objects, photographing them is just as important.
If Oumuamua is a spacecraft, why did its pilots not contact us?
Because it is in perdition, which explains why it turns on itself. I think it's a probe like both Voyager and New Horizon, which will eventually leave the Solar System. I believe that the search for extraterrestrial life should include archaeology, that is, the search for extraterrestrial technological artifacts.
Are there other avenues for extraterrestrial archaeology?
We could, with the future James-Webb space telescope, detect pollution on an exoplanet in orbit around a white dwarf [very faint star]. It would require a level of pollution 100 times higher than on Earth, but it is possible.
In your book, you mention the discovery, in September, of phosphine, a gas probably produced by microbes, on Venus.
It wouldn't cost NASA very much to check for microbes in Venus' atmosphere, but there are only for Mars. That said, we can have a scientific debate. Since then, the authors have redone their calculations and the biochemical anomaly would be three times smaller, although it remains statistically significant, and another study has shown that it could be something other than phosphine.
Extraterrestrial – The first sign of intelligent life. Avi Loeb. Editions de l'Homme. 272 pages.
The opinion of three Quebec astrophysicists
I note the very large number of scientific articles published since its discovery by people who have spent their lives studying asteroids, comets and other objects in the Solar System. Loeb stands apart. The artificial origin of this object is a rather extraordinary hypothesis which, as the saying goes, requires extraordinary proof.
Laurent Drissen, professor of astrophysics at Université Laval
Although in science we must always keep an open mind, Oumuamua is in all likelihood a natural asteroid outside the Solar System and not an object of extraterrestrial manufacture!
René Doyon, professor in the physics department of the University of Montreal
We know it's an object passing through our solar system. And we know he has a distant form. Not a sphere, but rather a cigar. However, to conclude from this that it is an outer spacecraft is in my opinion really far-fetched.
Björn Benneke, professor in the physics department at the University of Montreal
Asteroids in numbers
1: Number of asteroids or comets from another solar system, of a size similar to that of Oumuamua, which are at any time inside the Earth's orbit around the Sun
100: Number of asteroids or comets from our solar system, of a size similar to that of Oumuamua, which are at any time inside the Earth's orbit around the Sun
2500 billion billion: Number of asteroids or interstellar comets that sail from one solar system to another in our galaxy, the Milky Way
Sources: Harvard University, Forbes
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