NASA/ESA/ST ScI
At the end of 2017, our solar system received its first known interstellar visitor. It’s called Oumuamua (Hawaiian for “first messenger to arrive from afar”), a strange cigar-shaped object that zips past at 44 kilometers per second. Was it a comet? asteroid? Alien technology? Since then, scientists have puzzled over Oumuamua’s origins and anomalous features, especially its strange trajectory, and have proposed various models to explain them.
But perhaps the answer is much simpler than previously thought. That’s the conclusion of a new paper published in Nature. “‘Oumuamua’s bizarre behavior is the result of the release of hydrogen when the icy object warms up near the Sun, a simple mechanism common to icy comets,” the authors wrote. suggests.
As previously reported, “‘Oumuamua was first discovered by the University of Hawaii’s Pan-STARRS1 telescope, part of NASA’s Near-Earth Observation Program that tracks asteroids and comets coming close to Earth. Other telescopes around the world were soon set to work, measuring various properties of the object.
Astronomers were surprised to discover that ‘Oumuamua was moving away from the Sun much faster than gravity alone could explain. It showed no signs of the typical gas and dust expulsion when a comet approaches the Sun. Its elongated cigar-like shape combined with its relatively rapid rotation suggested early that it might be an asteroid.
Some astronomers have suggested that “‘Oumuamua may be a fragment of another, larger parent body in another solar system. Interstellar bodies may be produced by extensive tidal breakup during a close encounter with a parent star and then ejected into interstellar space, or dislodged by a collision about 500 million years ago. They may be fragments of exoplanets that have been ejected from their parent star systems, such as Neptune’s moon Triton, which has characteristics similar to those of Pluto covered in nitrogen ice. It must have been.
In October 2018, Harvard University astronomer Avi Loeb and then-postdoc Shmuel Beery submitted a preprint (after publication) to the Astrophysical Journal about the strange acceleration and strange orbit. As we reported at the time, much of their analysis discussed the possibility of solar radiation pressure, or the momentum transfer of photons striking objects (the driving idea behind the “solar sail”). I was. Loeb and Bialy sparked controversy by suggesting that the object may actually be a very thin solar sail.
