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Could that be our first contact with extraterrestrial technology?

Image credit: NASA / ESA / Hubble / ESO / M. Kornmesser.

"1I/2017 U1 'Oumuamua" — the first known interstellar object within the Solar System

In October 2017, a vague point of light was detected by the Pan-STARRS 1 telescope in Hawaii. At first, it looked like a typical small asteroid, but later observations made it possible for astronomers to figure its orbit more accurately. It turns out that it didn't match the behavior of any other asteroid or meteor observed so far. The enigmatic stranger, which was called 'Oumuamua flew past the sun, coming from 'above' the plane of the planets on a highly inclined orbit, with speed fast enough to escape the Sun's gravitational pull and eventually head out of our Solar System, speeding up.

Initially, it was assumed that the object is an interstellar comet since they are thought to be more numerous than interstellar asteroids. The problem was that there wasn't any trace of the typical hallmarks of cometary activity – no evidence of gas emission or dust. Therefore, there is no clue how does it change the anticipated trajectory of its orbit and why does it accelerate its speed.

The initial research. A comet or an asteroid?

After the initial discovery, Dr. Marco Micheli and his colleagues, all from ESA's SSA-NEO Coordination Centre continued to make meticulous measurements of 'Oumuamua with the help of NASA/ESA Hubble Space Telescope, ESO's Very Large Telescope, the Canada-France-Hawai'i Telescope, ESA's Optical Ground Station telescope, and various other telescopes around the world.

"Unexpectedly, we found that Oumuamua was not slowing down as much as it should have due to just gravitational forces. What could be causing this curious behavior?" said Dr. Micheli. And then added: "We think this is a tiny, weird comet. We can see in the data that its boost is getting smaller the farther away it travels from the Sun, which is typical for comets".

But there is no registered evidence of dust or larger grains around the object. As Dr. Karen Meech, from the University of Hawaii, said: "'Oumuamua is small and it could have been releasing a small amount of relatively large dust for it to have escaped detection." But the more realistic point of view was latterly added: "To really understand Oumuamua we would need to send a space probe to it. This is actually possible, but it would be very expensive and take a long time to get there, so it isn't practical this time. We just have to be ready for the next one."

Image credit: ESA.

The figure renders the orbit of 'Oumuamua as it passes through the Solar System. It shows the predicted path of the object and the new course, taking the new measured velocity of 'Oumuamua into account. The unknown object passed the distance of Jupiter's orbit at the beginning of May 2018 and will go through Saturn's orbit in January 2019. It will approach Uranus' orbit in August 2020 and the orbit of Neptune in late June 2024. 'Oumuamua will get as far as the outer edge of the Kuiper Belt, and then will reach the heliopause — the edge of the Solar System — in November 2038.  

An artist’s impression of the interstellar object ‘Oumuamua. Image credit: M. Kornmesser / ESO.

 The theory of Professor Abraham (Avi) Loeb

Three years later, the Harvard professor Professor Abraham (Avi) Loeb claims in his newly released book - Extraterrestrial: The First Sign of Intelligent Life beyond Earth. - that 1I/2017 U1 'Oumuamua, a fast-moving, cigar-shaped object of extrasolar origin discovered close to Earth in October 2017, was most probably "a piece of advanced technology created by a distant alien civilization."

"Long before we knew of its existence, the object was traveling toward us from the direction of Vega, a star just 25 light-years away," writes Professor Loeb. Adding: "It intercepted the orbital plane, within which all of the planets in our Solar System revolve around the Sun, on September 6, 2017. But the object's extreme hyperbolic trajectory guaranteed it would only visit, not stay."

"On September 9, 2017, the visitor reached its perihelion, the point at which its trajectory took it closest to the Sun. Thereafter, it began to exit the Solar System; its speed far away — relative to our star, it was moving at about 94,800 km per hour (58,900 miles per hour) — more than ensured its escape from the Sun's gravity. It passed through Venus's orbital distance from the Sun around September 29 and through Earth's around October 7, moving swiftly toward the constellation Pegasus and the blackness beyond."

The following highly-detailed observations made by both ground- and space-based telescopes detected the sunlight reflected off the surface of 'Oumuamua. There was a large fluctuation of its brightness, suggesting that the interstellar object is highly elongated and up to 275 m (900 feet) in its longest dimension.

"As soon as the observatory in Hawaii announced its discovery, and even as 'Oumuamua was fleeing toward the outer Solar System, astronomers around the world trained a variety of telescopes on it. The scientific community was, to put it mildly, curious," Professor Loeb writes in the book.

"One pressing question was: What did 'Oumuamua look like? We did not, and do not, have a crisp photograph of the object to rely on. But we do have data from all those telescopes that were dedicated for about 11 days to collecting whatever they could. And once we had our telescopes trained on 'Oumuamua, we looked for one bit of information in particular: how 'Oumuamua reflected sunlight. For astrophysicists, an object's changing brightness provides invaluable clues to its shape. In the case of 'Oumuamua, the object's brightness varied tenfold every eight hours, which we deduced to be the amount of time that it took to complete one full rotation," he adds.

"This dramatic variability in its brightness told us that 'Oumuamua's shape was extreme, or at least five to ten times longer than it was wide. To these dimensions, we added further evidence about 'Oumuamua's size. The object, we could say with certainty, was relatively small."

The professor's book

Extraterrestrial: The First Sign of Intelligent Life beyond Earth takes us on the mind-boggling journey of the first interstellar visitor to our Solar System. In the book, Professor Loeb argues that 'Oumuamua is neither a comet nor an asteroid, therefore it should be artificial object, maybe part of some advanced technology made by some distant alien civilization.

"Our civilization has sent five man-made objects into interstellar space: Voyager 1 and Voyager 2, Pioneer 10 and Pioneer 11, and New Horizons. This fact alone is suggestive of our unlimited potential to venture far out. So too is the behavior of our more distant ancestors. And if other civilizations developed out there among the stars, wouldn't they have felt that same urge to explore, to venture past familiar horizons in search of the new? Judging by human behavior, that would not be surprising in the least."

Professor Loeb's book is set to be published by Houghton Mifflin Harcourt on January 26, 2021.

Source: http://www.sci-news.com

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