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The first known interstellar visitor just got a little weirder. New observations with the Hubble Space Telescope reveal that 'Oumuamua is actually a comet spewing ice and dust, instead of a rocky asteroid.
Astronomers made the discovery while trying to follow the path of Oumuamua, learning from which direction it came before hissing in our solar system in October 2017. The object flew over the Earth on a trajectory our solar system, where planets, moons and other worlds tend to surround our sun. His strange path, coupled with his high speed, led astronomers to conclude that "Oumuamua (pronounced oh-MOO-ah-MOO-ah) must be a visitor of another solar system.
The team used Hubble because it is above the earth's atmosphere, which allows it to observe weak objects, studies co-author Karen Meech, Global Astronomer at the Institute of Astronomy of the University of Hawaii. . "To our surprise, starting in November, our measurements began to show that" Oumuamua was accelerating – in other words, its path was not controlled only by the gravity of the sun and planets. all but one … this gas coming from Oumuamua gave him an extra boost. "
This means that" Oumuamua behaves more like a comet.The solar system has many types of small worlds, including asteroids and comets.Asteroids are usually space rocks or rubble piles, while comets have ice in and near their surface.When comets near the sun and the sun warm the ice, the ice turns into gas and pushes against the comet.
Meech has explained that this thrust can alter the path of the comet through space.Hot comets also emit a lot of gas and dust in a cloud called coma.But when astronomers have tried to find the evidence of a coma around Oumuamua, their research proved to be empty.They theorize that it is because "Oumuamua is smaller, making the gas difficult to detect, or that he has lost most of his grai ns of smaller size during his trip. What is left are larger dust grains, which are more difficult to push off the surface.
But the difficulty in making the observations, she explained, is "Oumuamua is the first known interstellar visitor. There are no other objects like Oumuamua that scientists can compare – at least until we find another interstellar visitor.
The discoveries of "Oumuamua" were published in the journal Nature . Marco Micheli from the European Space Agency is leading the study.
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