Mystery of our first interstellar visitor may be solved

Was it an asteroid, comet, or even an alien spaceship ? For years, astronomers have been perplexed by ‘Oumuamua, a mysterious object up to 400 meters long that entered the Solar System in 2017. No such object from beyond our Sun’s reaches had visited us before, with this interloper moving so fast it could not be bound to the Sun. ‘Oumuamua, as scientists christened it, was also odd in that it looked like an asteroid but behaved like a comet. Now, a team of researchers says ‘Oumuamua was definitely a comet , albeit one with an unusual makeup. “We can explain a lot of the strange behavior,” says Jennifer Bergner, a chemist at the University of California, Berkeley, who led the work, published today in Nature . The study is “the most convincing model so far” for ‘Oumuamua, says Marco Micheli, an astronomer at the European Space Agency in Italy who was not involved with the work. The alien visitor, he says, was actually not so different from Solar System comets. ‘Oumuamua was first spotted on 19 October 2017. A telescope in Hawaii spied it as it made its way past the Sun, reaching a top speed of 87 kilometers per second—too fast to have originated in the Solar System. Astronomers named the object 1I/2017 U1 (‘Oumuamua), Hawaiian for “a messenger from afar arriving first.” NASA’s Hubble and Spitzer telescopes found that ‘Oumuamua had an oddly elongated, cigarlike shape bet...
Source: ScienceNOW - Category: Science Source Type: news