Wednesday , March 3 2021

Why not post strangers & # 39; about the interstellar space

The head of the Harvard Department of Astronomy thinks there is a possibility that a weird object that has visited our solar system from the interstellar space can be an extraterrestrial senton sent from a far civilization. He and colleagues presented their idea in a paper released this week by analyzing what could be a mysterious spatial object, putting media rage on them.

But let's breathe before we cheerfully cry "aliens." A unique idea of ​​what this item is could they do not make it just an explanation, and many scientists still argue that the natural explanation is more convincing. To add a little context, one of the scientists who made this "exotic" claim is currently working on a search for extraterrestrial life in the deep universe, sends probes from Earth to other star systems.

The work that attracted all attention was written by Harvard astrophysicists Avi Loeb and Shmuel Bialy, who were trying to describe some strange behavior exposed to the spatial rock called 'Oumuamua'. Observed last October, "Oumuamua is a mysterious object that goes through our solar system, which comes from an unknown deep origin. These objects think they go through our Sun system, but this is the first ego comet – or comet outside our cosmic neighborhood – which we've ever found out.

In addition to being a rare find, "Oumuamua is somewhat bizarre, and astronomers expected such a visitor to be an ice comet, surrounded by a gas and dust track, while passing near the Sun. However, it seems that Oumuamua is missing such a cloud, which looks more like an asteroid it is mostly composed of rocks and metals, so nobody was sure what it was – a comet, an asteroid, or something new – then, after the Oumuam's orbit, scientists from the European Space Agency have noticed that the object accelerated, more than it should be, if it is only interaction with the gravity of the planet and the Sun in our Solar System. They concluded that "Oumuamua must be a comet; The sun probably warms the ice inside the object, creating gas that provides extra speed.

Graphics showing 'Oumuamua's way through the Sun's system.
ESO / K. Meech et al.

However, Loeb and Bialy are skeptical of this "exit" claim, mainly because no one was able to observe the gas and dust coming from Oumuamua. They also point to recent research from another lab that is still being reviewed by other scientists, suggesting that if the gas from this facility came, it would change the way rotation rotates – something that was not observed. "This excludes the possibility of being a comet," says Loeb Border.

That's why they decided to look at another possible explanation for acceleration: can Oumuamua be faster thanks to the light from the sun? Sunlight can actually work on objects, giving them a light boost. Perhaps this phenomenon is enough to explain why Oumuamua is getting faster. However, if this mechanism – known as the sun's radiation pressure – is guilty of extra speed, then "Oumuamua must have been extremely light and super thin, only one millimeter thicker.

This gave Loeb the idea that "Oumuamua can be what is known as a lightweight sail – a thin artificial nautilus that drives in the sun. And this light sail may actually be sent here deliberately." The more exotic scenario is that "Oumuamua can be a fully operational probe sent deliberately to the land close to the extraterrestrial civilization, "he and Bialy wrote in his work.

Loeb has been dealing with light sails for years. He is the chairman of the Advisory Board for Breakthrough Starshot, an initiative that requires sending a super-lightweight light sailboat to interstellar space, powered by a giant laser. Loeb admits that his work with Starshot gave the idea that "Oumuamua may be a strange light on the sail." Our imagination is limited to what we know, "he says." And the fact that I'm involved in a project that uses light sailing, has allowed me or encouraged me to think about it. "

Loeb says he welcomes other explanations that do not involve strangers, but he is pretty sure his idea is correct. "I can not remember another explanation for the peculiar acceleration of" Oumuamua, "he says.

But other scientists claim that a natural explanation can still be valid here. Just because we did not see gas and dust from Oumuamu does not mean that the material is not there. Scientists only had about two weeks to observe this object at the end of October before it was too far from Earth and it was incredibly weak to be able to see telescopes based on the ground. Hubble's Space Telescope was then the only tool we had to observe & # 39; Oumuamua & # 39; until December, and the observatory mostly follows its orbit around the sun.

That is why it is quite possible that the telescopes we watched with "Oumuamua simply could not see the material flowing from the object, which may be because we did not observe the object in true light, or some key telescopes were not available to watch this peculiar cosmic rock." and the weather times with which telescopes on the planet we could not potentially see dust, "said Michele Bannister, an astronomer who studied Oumuamua at Queen's University in Belfast, but was not involved in this research, says Border.

Comet ISON and his tail gas and dust, as he saw the Hubble Space Telescope
Image: NASA

It is also possible that "Oumuamua simply does not emit a lot of dust, which would make the effect of spilling more difficult to observe." You can blend it with a comet similar to a similar object, "says Bannister." It just does not leave as much dust as normal comets. "Comet in our The Sun's system usually releases innumerable microscopic particles of dust that reflect the sun's visible light from the Earth.If Oumuamua does not have a lot of dust on the surface, then it can only discharge the gas, which is easier to miss, and there are examples of such objects in their own Solar "We have comets we know – rare comets that have to be said – in our solar system that emits so little dust that you have to look for gas to see the outcome," Alan Fitzsimmons, astronomer at Queen's University Belfast, who wrote the article explaining how "Oumuamua can be a comet, he says Border.

Normally, astronomers believe that good practice is to exhaust all possible natural explanations for the observed phenomenon before resorting to a foreign argument. There is a quotation, popular by astronomer Carl Sagan, which many astronomers resort to when strangers support the explanation: "Extraordinary demands require extraordinary evidence." Most agree that there is no extraordinary evidence to support the demand for lightboards. "Every observation we have on this facility comes with enormous insecurity because we have very little information about it," says Katie Mack, theoretical astrophysicist at North Carolina University BorderIf anything, this extraterrestrial artifact seems to be out of control because of the chaotic decay through our solar system. "If it was an extraterrestrial aircraft, it was Brexit's extraterrestrial aircraft. It was a complete freeze," says Fitzsimmons.

However, sometimes astronomers will write wild theories like this, so that those in the community can share that claim and break it apart. "Sometimes you write an article about something you do not believe is true, just to put it there," says Mack. Loeb, on the other hand, does not want people to discredit their idea just because it could be inflammatory. "We should not deny this possibility just because some people do not like to hear it," he says. "It is important that we do not have to be prejudiced in science. We should base our conclusions on evidence, about information, not about prejudices. "

But whenever aliens are called, this is usually an explanation that gets the most attention. A similar situation occurred in 2015, when astronomers suggested the idea that the strange behavior of a distant star could explain foreign megastructures in orbits of the stars. The theory, which many were skeptical, became so omnipresent that the star eventually became the star of the "alien megastructure".

Of course, there is a possibility. But aliens are a very brave request to be made when natural explanations are still on the table. "I can understand excitement, and as a scientist I can not sit here and say I have 100 percent proof that it's a natural object," Fitzsimmons says. "Only that all observations can be adapted to a natural object."

And that could be a problem when we actually did makes one day, there are signs of extraterrestrial life. Astronomers constantly find new planets outside our solar system, and we are doing more sophisticated technology to get into the atmosphere of these worlds. One day, we can find solid evidence that life exists in a deep space, but it can be difficult for the public to swallow if they think the aliens are already discovered. "I do not want people to think we've seen it when that really happens," says Mack. "I want people not to be super cynical about alien claims until the moment we really have something that's really solid evidence."

Mary Beth Griggs contributed to this report.

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