Avi Loeb, a prominent astrophysicist and director of Harvard's Astronomy Unit, recently said that our solar system was visited by an alien vessel. Information that electrified all the press. It refers to Oumuamua, which almost all astrophysicists have identified as a natural asteroid outside our solar system, and which passed through it for ten days in 2017. But for the Harvard astrophysicist, it could be act of a solar sail, a vessel coming from another civilization perhaps disappeared. To take stock, Sean Raymond, astrophysicist and researcher at LAB, the Bordeaux Astrophysics Laboratory, answers Nicolas Martin's questions. Is Oumuamua an extraterrestrial vessel? Sean Raymond: "I would say no, probably not. We can't be 100% certain, we have to admit that because we don't have a photo that shows us exactly what it is, but depending on what understand, we don't need to make that assumption. " Why is there no photo of Oumuamua? Sean Raymond: "It's very dark, it was discovered moving so fast in the sky that we barely saw it. It was right at the detection limit of the telescopes. It's just that it ' was too small and too dark. It fits in a pixel of the camera and it moved so fast that we had a window of about 10 days of observation. And we did what we could but we didn't couldn't get a photo where you can really see the shape of the object. " Why did we have so little time to see it? Sean Raymond: "It is the first interstellar object that we know of. We know in relation to its speed that it comes from outside the solar system. It approached quite close to the Sun and it went to the inside the orbit of Mercury. And we found it when it started again. And it was moving so fast 70 kilometers per second, that it was found by a telescope that is created to search for moving objects, to find asteroids that can potentially approach Earth. So we found this, we did our best to follow it as quickly as possible, but it dimmed very quickly. So we know its orbit, its trajectory, well. we know them quite well. But we know very little about their physical characteristics. " Why does Avi Loeb, astrophysicist, director of Harvard's astronomy unit, claim that it is an alien vessel? Sean Raymond: "He says it must be something extraterrestrial because all natural explanations don't work. This is where I don't agree because, of course, we don't know everything but he there are natural explanations that progress. " What observations is it based on? Sean Raymond:So, it's not brilliant. If we see it like that , we see a lot more surface that reflects the sun, it's brighter. So, with that argument, we can ask ourselves: "What is it as an object?" It is quite rare in the solar system to have such large objects. And Avi Loeb proposed that it be something stretched out like that and that is a solar sail . " have such extensive objects. And Avi Loeb proposed that it be something stretched out like that and that is a solar sail . " have such extensive objects. And Avi Loeb proposed that it be something stretched out like that and that is a solar sail . " If it is not a solar sail, how to explain the variation in luminosity? Image captured from above video clip shows artist\u2019s interpretation of \u2018Oumuamua as it approaches our Solar System. The object rotates approximately once every 7.4 hours based on the data used in this research. Credit: Gemini Observatory\/AURA\/NSF image by Joy Pollard Sean Raymond: "There are now four or five explanations of natural processes that can create very large objects. It's not that we have zero objects that are like that, it's just that we have very little. data for small objects. Among the small objects there are some examples of objects which vary a lot in brightness. And it is possible that they are extended like Oumuamua. But we have very little data because it is very hard to observe them just like Oumuamua. " What is the other argument advanced by Avi Loeb? Sean Raymond:used to see? And so Avi Loeb jumped on it and said, "Ah, there's no way it's a comet." " Avi Loeb explains that no one wants to believe it's an alien ship on principle ... Sean Raymond: "I think what he doesn't understand is that all astronomers are motivated. There has been an explosion of interest in exoplanets, in exobiology, in the possibility of life elsewhere and of do it in a rigorous way. The vast majority of astrophysicists I know are doing astrophysics now because they've seen Star Wars, Star Trek. They've been motivated by science fiction from the start. We'd love to find something. something that is extraterrestrial. We all look for it and we all take it into consideration in our research. And we are all a little bit disappointed when we look at the models and "oh no shame, that does not work" and we start testing other hypotheses. "