Meet 'Oumuamua, the first observed interstellar visitor to our solar system

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When astronomers using the Pan-STARRS1 telescope in Hawaii spotted a mysterious object dashing through our solar system on October 19, they immediately knew it was something special. Astronomers have found around 750,000 of the giant space rocks floating around our solar system.

The first object ever known to enter our solar system from beyond is not your average asteroid or comet. "'Oumuamua had already passed its closest point to the Sun and was heading back into interstellar space". They had to be speedy, given that the object is now moving 95,000 kilometres per hour and heading away from the sun.

The team is composed of Karen J. Meech (Institute for Astronomy, Honolulu, Hawai'i, USA [IfA]) Robert Weryk (IfA), Marco Micheli (ESA SSA-NEO Coordination Centre, Frascati, Italy; INAF-Osservatorio Astronomico di Roma, Monte Porzio Catone, Italy), Jan T. Kleyna (IfA) Olivier Hainaut (ESO, Garching, Germany), Robert Jedicke (IfA) Richard J. Wainscoat (IfA) Kenneth C. Chambers (IfA) Jacqueline V. Keane (IfA), Andreea Petric (IfA), Larry Denneau (IfA), Eugene Magnier (IfA), Mark E. Huber (IfA), Heather Flewelling (IfA), Chris Waters (IfA), Eva Schunova-Lilly (IfA) and Serge Chastel (IfA). This complex and convoluted shape means the object varies incredibly in brightness. During the few weeks when it was visible, it varied wildly in brightness, consistent with an elongated object that's rotating about its axis.

So what is it? The authors of the study describing 'Oumuamua write that "immanent upgrades to contemporary asteroid survey instruments and improved data processing techniques are likely to produce more interstellar objects in the upcoming years".

But the object has another official name: 'Oumuamua. The correct forms for referring to this object are now: 1I, 1I/2017 U1, 1I/'Oumuamua and 1I/2017 U1 ('Oumuamua). "And now that we have found the first interstellar rock, we are getting ready for the next ones", Hainaut said.

Our solar system recently had a very odd visitor.

Possibly 10 times longer than it is wide, its elongated shape is unlike that of any asteroids seen in our solar system. So it would stand to reason that other planetary systems are sending the same remnants our way.

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According to the European Southern Observatory, an interstellar asteroid probably flies through our solar system about once per year, however, we haven't seen them until now due to their extremely fast speed and faint appearance.

Based on preliminary calculations of its orbit, astronomers have deduced that it came from the general direction of Vega, the brightest star in the northern constellation of Lyra.

However, even travelling at an incredible speed of 95,000 kilometres per hour (59,000 miles per hour), it would have taken 300,000 years to reach Earth from Vega - and Vega wasn't in the same place 300,000 years ago.

The astronomers believe that instead, the object could have been traveling through our home galaxy, the Milky Way, for hundreds of millions of years, without being attached to any star system, before reaching us.

"Certainly this is a new type of object".

"While study of 'Oumuamua's colors shows that this body shares characteristics with both Kuiper Belt objects and organic-rich comets and trojan asteroids", says Meech, "its orbital path says it comes from far beyond".