Friday , May 7 2021

Why should not we cry "aliens" about the interstellar spacebar yet?



The head of Harvard's astronomical department believes there is a possibility that a strange object that visited our solar system from interstellar space could be a strange probe sent from a remote civilization. He and a colleague explained his idea in a paper published this week and analyzed what the mysterious space object could be and resigned from a media frenzy.

But let's take a breath before we cheer out crying "aliens." A single idea of ​​what this object could Be it not the only explanation, and many researchers still claim that a natural explanation is more credible. To add a little context, one of the researchers who makes this "exotic" statement currently an initiative to search for extraterrestrial life in deep space by sending earthquakes to other star systems.

The paper that caught everyone's attention was written by Harvard astrophysicist Avi Loeb and Shmuel Bialy, who attempted to describe a certain behavior depicted by a space rock called `Oumuamua. Spotted in October, `Oumuamua is a mysterious object that passes through our solar system, which comes from an unknown deep space. Objects like this one mean throughout our solar system, but this is the first exo comet – or comedies from our cosmic neighborhood – that we have ever discovered.

In addition to being a rare discovery, `Oumuamua is a bit bizarre. Astronomers expected that a visitor of this kind would be an odd comet, surrounded by a trace of gas and dust as it passed near the sun. But `Oumuamua seems to miss this kind of cloud, which makes it look more like an asteroid, most often made of rock and metal. So nobody was absolutely sure what this was like – a comet, an asteroid or something new. Then, after analyzing the `Oumuamoa's orbit ', researchers from the European Space Agency discovered that the object was accelerated, more than it would be if it only interacted with the planet's and the sun's gravity in our solar system. They concluded that "Oumuamua must be a comet; the sun is likely to heat ice within the object, creating gas that gives an extra speed boost.


A graphic showing 'Oumuamuas road through the solar system.
ESO / K. Meech et al.

Loeb and Bialy, however, are skeptical of this "exhaustion" claims, mainly because no one could observe gas and dust coming from `Oumuamua. They also point to new research from another laboratory, which is still being reviewed by other researchers, indicating that if gas comes from this object, it would change how the cradle rotates – something that has not been observed. "This regulates the possibility that it's a comet," says Loeb The limit.

So they decided to look at another possible explanation for the acceleration: can `Oumuamua be faster thanks to light from the sun? Our Sun's light can actually exert force on objects, giving them a small print. Perhaps this phenomenon is enough to explain why `Oumuamua is getting faster. But if this mechanism, so-called solar radiation pressure, is due for extra speed, `Oumuamua must be extremely light and super thin, only one millimeter thick.

It gave Loeb the idea that `Oumuamua could be what is called a light sail – a thin artificial sail that rides on sunlight. And this lightweight sail can actually have been sent here with the intention. "A more exotic scenario is that` Oumuamua can be a fully functional probe that is sent purposely to the earth's proximity to an extraterrestrial civilization, "he writes and Bialy in his paper.

Loeb has been watching light sail for several years now. He is the chairman of the Breakthrough Starshot Advisory Board, an initiative that requires sending a supertight light sailing spacecraft in interstellar space driven by a giant laser. Loeb admits that his work with Starshot gave him the idea that `Oumuamua could be an extraterrestrial easy sail. "Our imagination is limited to what we know about," he says. "And the fact that I'm involved in a project that easily uses the sail made it possible for me or invited me to think about it."

Loeb says he welcomes other explanations that do not involve foreigners, but he is quite sure that his idea is correct. "I can not think of another explanation for the special acceleration of" Oumuamua, "he says.

However, other researchers claim that a natural explanation can still be applied here. Just because we have not seen gas and dust coming from `Oumuamua does not mean that this material is not there. Researchers had only about two weeks to observe this item again in late October before it became too far from the ground and became extremely weak to see with terrestrial telescopes. The Hubble Space Telescope was then the only tool we had to observe `Oumuamua until December, and the observatory mostly tracked its orbit around the sun.

So it is quite possible that the telescopes we used to observe `Oumuamua just could not see material floating outside the object. This may be because we did not observe the item in the right light, or some crucial telescopes were not available to see this particular spacecraft. "Because of the weather and which weather occurred with which telescopes on the planet we could not see the dust," Michele Bannister, an astronomer who studied "Oumuamua at Queen's University Belfast, but was not involved in this research, tells The limit.


The comet ISON and its tail of gas and dust, seen by the Hubble Space Telescope
Image: NASA

It is also possible that `Oumuamua does not emit much dust, which would make this blowing effect more difficult to observe. "You can fit this with a straight comet-like item," says Bannister. "It just does not have to emit as much dust as usual comets do." Comets in our solar system usually release numerous microscopic dust particles that reflect sunlight, which can then be seen from the ground. If `Oumuamua does not have much dust on the surface, it can only let out gas, which is easier to miss. And there are examples of such items in our own solar system. "We have comets we know – rare comets that must be said – in our solar system, which emits so little dust that you have to look for the gas to actually see the result," Alan Fitzsimmons, an astronomer at Queen's University Belfast, who wrote a paper explaining how `Oumuamua can be a comet, tells The limit.

Generally, astronomers find that it is good to exhaust all possible natural explanations of an observed phenomenon before resorting to the foreign argument. There is a quote, popular with the astronomer Carl Sagan, which many astronomers resort to when foreigners are stuffed as an explanation: "Extraordinary claims require extraordinary evidence." Most agree that there is no additional evidence to back up easy sealing languages ​​right now. "Every observation we have about this object comes with great uncertainty because we have very little data about it," said Katie Mack, a theoretical astrophysician at North Carolina State University, The limit. If anything, it seems that this strange artefact is out of control, because it chaosically tumbles through our solar system. "If it was a strange spacecraft, it was Brexit of Alien Spacecraft. It was a complete muck-up," said Fitzsimmons.

But sometimes astronomers will write up wild theories like this so that in society they can dissect the statement and choose it from each other. "Sometimes you write a paper about something that you do not believe in being true at all, just to put it out," says Mack. Loeb, on the other hand, does not want people to discredit their idea just because it can be inflammatory. "We should not reject this opportunity just because some people do not like to hear it," he says. "The point is that we should not benefit from science. We should base our conclusions on evidence, data and not prejudice. "

But when foreigners are made, it is usually the explanation that gets the most attention. A similar situation occurred in 2015, when astronomers suggested the thought of a strange star's strange behavior can be explained by extraterrestrial mega structures in the star's path. The theory, as many have been skeptical, became so ubiquitous that the star was eventually referred to as "the main mega structure" star.

Of course there is the possibility. But aliens are a very bold statement to do when natural explanations still remain on the table. "I can understand the excitement, and as a researcher, I can not sit here saying that I have 100 percent proof that this was a natural object," says Fitzsimmons. "It's only that all observations can be matched with a natural object."

And that can be a problem when we actually do Find a sign of strange life one day. Astronomers always find new planets outside our solar system, and we work with more sophisticated technology to compare to the atmospheres of these worlds. One day we can find solid evidence that life is in deep space, but it can be difficult for the public to swallow if they think foreigners have already been discovered. "I do not want people to believe we already saw when it really happens," Mack said. "I want people not to be super cynical about claims of aliens when we actually have something that is really solid evidence."

Mary Beth Griggs contributed to this report.


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