[ad_1]
A mysterious, strangely elongated object that streaks through our solar system is probably a comet. This is the conclusion of astronomers who used the Hubble Space Telescope and 27 ground-based telescopes to scan the interstellar visitor, which was first detected on 19 October. It is the first object ever seen beyond our planetary neighborhood.
report, published Wednesday in the journal Nature, will not close the book on what has been named 'Oumuamua, for the Hawaiian word meaning' scout '. Even though it's a comet, it's a strange comet.
Oumuamua with a telescope in Hawaii, they struggled to classify it. A comet seemed the best guess, because such things are predicted by theorists to arrive from deep space regularly. But it did not look like a comet. It lacked a visible atmosphere. He had no coma, no tail.
Astronomers quickly changed the classification of the comet into an asteroid, and then changed it to an "interstellar object." He is the only member of this exclusive club.
Predictably, the mystery object has prompted speculation – at least among those with speculative penchant – that it could be artificial. Sci-fi fans have noted that Arthur C. Clarke's novel "Rendezvous With Rama" of 1973 focuses on a presumed asteroid of interstellar space that, after further inspection, is unmistakable. turns out to be a giant alien spacecraft. Although conjectured extraterrestrials are a recurring nuisance for serious scientists, in this case there was enough oddity in Oumuamua that some astronomers were using the large radio telescope from Green Bank, West Virginia, to see if that could possibly be the case. Signal broadcast
did not look like a comet at any point in his journey. But his movement through the solar system suggested that he emitted gas from his interior when it is heated by the sun, according to the report in Nature. By observing the object for many weeks from multiple telescopes, astronomers have been able to pick up the signature of a subtle shift in acceleration that matches the degassing comets. "We have explored a variety of possible physical mechanisms to explain the acceleration we have detected, and we have found that comet-like degassing works well, while the others can be excluded," said the spokesman. Lead author Marco Micheli, astronomer from a center of the European Space Agency in Frascati, Italy
. It seems cometary? Karen Meech, an astronomer from the University of Hawaii , said the tiny grains of dust that are usually found on the surface of comets and that have been blown out by degassing may have been eroded during Oumuamua's journey across the galaxy. cyanide, which is usually ejected from comets with water, they have not seen any. "We find that not all solar systems are going to have the same chemical ingredients when they are t assembled, "she said." Which is still what we would expect, but it's our first sample. "
Other astronomers are not ready to put the mystery for to rest.
"I will wait for the data submission with interest to run" I think that they found something interesting, but I'm not sure it's as clear as it is presented in the document, "Alan Jackson, an astronomer from the University of Toronto, said in an email." Jackson, who earlier this year co-authored an article describing "Oumuamua as an asteroid ejected from". 39, a double star system, noted this week that it "is a somewhat ambiguous object. The terms comet and asteroid are themselves somewhat ambiguous. The original and strict distinction between asteroids and comets is whether they have visible coma or not, and from this point of view "Oumuamua is an asteroid, because it is not."
Ames scientist David Morrison of NASA's Research Center, who said that the distinction between a comet and an asteroid can be a little "fuzzy". Sometimes an object can evolve over time – becoming more like one or the other, he said
. Case. "It has two unique things – it's the first object we've ever seen from another solar system, and its shape is different from anything we've ever seen," Morrison said. No one can say exactly what the dimensions are, but the best guess is that it's a half-mile long and only one-tenth of that diameter, according to Meech. "Cigar shaped" has been the common description.
Oumuamua entered the solar system after crossing the vacuum at 59,000 miles per hour. When approaching, it accelerated due to the gravitational field of the sun. In September, still unseen by the Terrans, he made his closest approach to the sun – about 24 million miles. It also reached a maximum speed of 196,000 miles per hour. The next month, he was close enough to Earth – 20 million miles – to be spotted by astronomers at the Haleakala Observatory on Maui.
His age is unknown. The object could likely be the oldest thing ever detected in our solar system – older than the planets, moons, asteroids and comets that formed with the sun there are about 4.6 billion # 39; years. It could have been ejected from another solar system when that was formed billions of years ago. In our own solar system, comets can be accelerated by the gravitational field of Jupiter as well as by the sun and reach the speed of escape, rushing into interstellar space.
Paul Chodas of NASA's Jet Propulsion Laboratory closely examined comets for decades, hoping to find one with a clearly interstellar origin. He had failed. "Oumuamua."
"Right away, it looked like an asteroid," Chodas said Monday. After several days of observing the object, astronomers realized that its trajectory and speed indicated that it had to come from beyond our solar system. The Planet Planet Minor at Harvard named it Asteroid 2017 U1
But in December came another rebound, when Micheli detected something odd in his move that suggested a factor other than the severity of the sun affecting the acceleration.
Chodas The crowd of alien ships may not be fully satisfied with the scientific explanation involving natural degassing. "It's not like a rocket or a spaceship, it's like a comet, it's the first thing to say," he said on Tuesday. "Secondly, interstellar space has just countless billions of these objects that are thrown into the formation of various solar systems."
Everything that can be learned at this point in Oumuamua must be gleaned from data already collected. pm Wednesday, it was already 595 million miles from the Earth, 13 times lower than anything the Hubble Space Telescope can detect and move to the middle of the galaxy.
He is already farther from the sun than the planet Jupiter. a few years, it will be farther from the sun than Neptune. The gravity of the sun slows him down but not enough to keep him. With clever symmetry, he will finally resume his interstellar cruising speed of 59,000 miles at the hour while he heads to the Pegasus constellation.
In theory, a space probe could be launched to catch Oumuamua and look closely. Do not count on that in an era of flat space budgets, however. Whatever it is, it's going away – and it will not be back.
[ad_2]
Source link
