We got a good look at the interstellar asteroid and it's weird

ESO: First Observed Interstellar Asteroid Is Incredibly Long, Has Red Color

An asteroid that visited us from interstellar space is one of the most elongated cosmic objects known to science, a study has shown. It is around 400 metres (a quarter mile) long, rocky and cigar-shaped with a somewhat reddish hue.

This suggests that Oumuamua could have been travelling through space, unattached to any star system, for hundreds of millions of years.

This diagram shows the orbit of the interstellar asteroid Oumuamua as it passes through the solar system.

"This history-making discovery is opening a new window to study formation of solar systems beyond our own", he added.

Unlike Solar System comets or asteroids, Oumuamua's orbit is not "bound to the Sun", Kotulla explained.

From there, no-one knows. Astronomers have trained a flurry of telescopes on the object discovered last month, and now we're being rewarded with super-exciting details.

Combining images from the various telescopes, an global team found that the asteroid varies in brightness by a factor of about 10 every 7.3 hours, matching its spin about its axis.

"This unusually large variation in brightness means that the object is highly elongated: about ten times as long as it is wide, with a complex, convoluted shape".

"For decades we've theorized that such interstellar objects are out there, and now - for the first time - we have direct evidence they exist", said Thomas Zurbuchen, associate administrator for NASA's Science Mission Directorate, in a statement.

We all know what asteroids and comets look like, right?

The observations and analyses were funded in part by NASA and appear in the November 20 issue of the journal Nature.

Initially it was believed that it came from within our solar system, but a look back at an image from the night before in the same general area revealed a trajectory that took the asteroid far outside our solar system, originating in the direction of the star Vega.

"The name, which was chosen by the Pan-STARRS team, is of Hawaiian origin and reflects the way this object is like a scout or messenger sent from the distant past to reach out to us (ʻou means reach ou for, and mua, with the second mua placing emphasis, means first, in advance of)", according to the Minor Planet Center.

But Vega was not even close to its present position 300,000 years ago, when its journey would have started. The object was reclassified as an interstellar asteroid and named 1I/2017 U1 ('Oumuamua) [1].

The International Astronomical Union, which is responsible for cataloging the names of space objects, also gave the asteroid its very first "I" for "interstellar" designation, which shifts its formal name from A/2017 U1 (with the "A" standing for "asteroid") to "1I/2017 U1".

While its elongated shape is quite surprising, and unlike other asteroids seen in our solar system, it may provide new clues into how other solar systems were formed. It is only recently that survey telescopes, such as Pan-STARRS, are powerful enough to have a chance to discover them.

Apparently, unlike many asteroids, 'Oumuamua doesn't have an icy tail behind it - possibly thanks to its spinning trajectory.

"We are continuing to observe this unique object, and we hope to more accurately pin down where it came from and where it is going next on its tour of the galaxy", observation team member Olivier Hainaut, from ESO in Garching, Germany, said in the ESO statement. "And now that we have found the first interstellar rock, we are getting ready for the next ones", Hainaut said.



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