Did a sunbed awning of an extraterrestrial civilization get us last year? Or was the object name "Oumuamua" even a fully functional spacecraft intentionally sent by aliens to Earth? If such questions are asked in a trade diary, many would doubt the seriousness of the study writers and publications.
But next to Shmuel Bialy, a junior researcher at Harvard University, he is also named Abraham Loeb at the current publication. "Loeb is one of the world's most respected theoretical astrophysics," said Kevin Heng, director of the Center for Space and Habitability at Bern University. "He is the head of the Astronomical Department at Harvard University and head of the Institute of Theory and Calculation." The study will not be published sometime next week, but in the prestigious journal "The Astrophysical Journal Letters."
An interstellar object
Although Loeb's reputation does not automatically mean that what the two researchers claimed in their release is true, Heng says. "But that means we should at least look carefully at what they propose."
In their publication, Loeb and Bialy take care of the extraordinary course "Oumuamua (Hawaiian for" Distant Messenger). The item was discovered on October 19, 2017 by the Pan-Starrs-1 telescope in Hawaii. At first it looked like a typical small asteroid moving at high speed. The closer observation, however, undoubtedly revealed that this celestial body is not derived from our solar system as everyone else observed before, but from the interstellar space, that is, from the stars.
"Oumuamua had more surprises in the store. A team of astronomers in Hawaii discovered that the brightness of the object was dramatically changing by a factor of ten when it rotates around its own axis every 7 hours. This strong light change means that" Oumuamua is very elongated so that it has the shape of a cigar or maybe a pancake. Its length is estimated to be at least 400 meters, and it runs through the solar system at a speed of approximately 300,000 kilometers per hour.
«Fully functional space probe»?
Recently, scientists around the Italian astronomer Marco Micheli in the journal Nature reported that Oumuamua has been accelerated in a way that can not be explained by the sun's gravity effects. The acceleration was as if it were a comet that emits gas. But in "Oumuamua" there was no evidence of gas emissions common to comets as they approach the sun.
If not remarkable, what could "Oumuamua have sped up?" Loeb and Bialy show that the acceleration can be explained if "Oumuamua is an extremely thin object driven by the sun wind. Only about 0.3 to 0.9 mm thick "Oumuamua should therefore be.
So what kind of object can it be? This question begins the more speculative part of the study. As Heng from Bern University says, Loeb is also the head of the Breakthrough Starshot Initiative, which aims to send a spacecraft to the nearest star. For the spacecraft would be equipped with a awning and powered by the solar wind. It is thus not surprising that the authors suggest that "Oumuamua can be a giant awful land that stirs as spacecrack from a remote civilization through our solar system and powered by the sun's wind.
Alternatively, the authors suggest an even more exotic scenario. Thus, Oumuamua can be a "fully functional spacecraft intentionally sent by an alien civilization near the earth," the publication says.
Maybe a comet
Martin Jutzi of the Space Research and Planning Department at the University of Bern finds the study "quite interesting". However, it would be very speculative just because of the observed non-gravitational acceleration of "Oumuamua on an awning or even a guided probe to close." In my opinion, it is always easier and better explanations. Of course, these are less sensational. »
Regardless of whether a sunscreen spacecraft could actually explain the observations, it is not clarified, says Jutzi. "A possible problem is the orientation of the extremely thin awning." Another is collisions with interstellar dust particles that would damage the seal. Although this issue is addressed in the paper, the potential mechanical damage caused by the collisions is not discussed.
As Marco Micheli writes in the aforementioned study in nature, it may well be that the potential exhaustion of Oumuamua was undetectable because it was below the detection limit. "In my opinion, the observed non-gravity acceleration can therefore be explained most easily by exhaustion," says Jutzi. "That means it's probably a comet-like object."
In our time, the search for artificial objects from other planetary systems is no longer science fiction.Kevin Heng, Head of Center for Space and Housing at the University of Bern
But even this scenario is controversial, "continues Jutzi. "It must be shown in detail that it works." Together, theoretical models would suggest that interstellar comets occur at some frequency in our solar system. "It may not need an exotic explanation, as evidenced by Bialy and Loeb's paper."
Unfortunately, it is already too late to investigate Oumuamua in more detail. The object is already too far from the ground to study it by telescope or visit it with a spacecraft. So there is no other choice, the researchers write, than to look for other items of this kind.
"It is one of the important messages in this publication," says Heng. "We live in a time when the search for artificial objects from other planetary systems is credible and no longer science fiction." Nothing can come from this search. But it's important that you can now test such ideas as Bialy and Loeb. "It's part of the scientific method."
Created: 07.11.2018, 18:00 clock