The cigar-shaped comet was discovered passing through the Solar System in 2017 and is now headed for the Pegasus constellation.
‘Omuamua moved like a comet, but did not leave the vapor trails normally seen behind a comet. The star was smaller than other comets, being several kilometers across.
Its elongated shape and other unusual features have led to many theories: alien probe, fragment of a distant planet, etc. However, scientists now say they know its origin and the answer is more unusual than previously theorized. According to a study published in the journal Science Nature Mercury, ‘Oumuamua is most likely an interstellar comet.
Before the arrival of the small celestial body, scientists had only observed comets that originated from the Solar System and had similar properties. NASA describes these comets as “the frozen remnants of the solar system’s formation, made up of dust, rock, and ice.”
As comets in the Solar System orbit the Sun, solar radiation heats them, causing jets of vaporous dust and gas visible from Earth, a comet tail.
The authors of this latest study, Jennifer Bergner and Darryl Seligman, say, ‘Omuamua may have a comet tail, but it’s invisible. ‘Because Oumuamua is much smaller than commonly observed comets, it may have produced a jet of hydrogen gas too small and thin to be detected by telescopes,’ wrote Jennifer Bergner and Darryl Seligman.
The way it traveled through the solar system also supports this idea.
According to NASA, cometary jets are strong enough to accelerate at certain points in their orbits, independent of the Sun’s gravity. Oumuamua accelerated as it passed through Earth’s inner solar system in comet-like fashion, but its lack of a visible tail suggested it was not a comet, leaving scientists confused about the source of its acceleration.
If the comet’s tail is too small to see, but strong enough to give it a boost, that could explain its characteristics, scientists said.