An artist's concept shows 1I/'Oumuamua, the first confirmed interstellar asteroid, which is about 10 times longer than it is wide. The asteroid was discovered in 2017, and it passed closest to Sun and Earth late in the year. Today it is returning to interstellar space on a high-speed trajectory. [European Southern Observatory/M. Kornmesser]
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An odd visitor passed through the inner solar system last year — an asteroid that appears to be shaped a bit like a tongue depressor or a bookmark.
The object was discovered in October. When astronomers calculated its path, they found that it’s not bound to the Sun. Instead, it came from outside the solar system. It passed within 24 million miles of the Sun — and even closer to Earth — before beginning its high-speed return to interstellar space.
The object was classified as an asteroid — the first confirmed asteroid from outside the solar system. It’s a slab of rock mixed with a lot of metal. It’s probably about a quarter of a mile to half a mile long, but only a tenth as wide. It’s also quite flat. It has a bumpy surface, and it’s dark red — the result of millions of years of bombardment by cosmic rays as it cruised through the Milky Way.
Because the asteroid was unlike anything astronomers had ever seen, they came up with a new way to designate it. It’s called 1I/‘Oumuamua. The “I” means it came from interstellar space, while the “1” means it’s the first of its kind. And the name “‘Oumuamua” comes from a Hawaiian name that means “scout.”
Today, ‘Oumuamua is returning to the stars — moving toward the constellation Pegasus, which is in the west as night falls right now. Look for a lopsided box of four stars, known as the Great Square. Soon, the asteroid will leave the solar system behind — an odd visitor headed back to the stars.
Script by Damond Benningfield