This object isn't supposed to be in our solar system

By Ashley Strickland, CNN

Updated 1305 GMT (2105 HKT) May 21, 2018

This illustration shows a massive star on the brink of explosion.
Photos: Wonders of the universe
This illustration shows a massive star on the brink of explosion.
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Meet the fastest asteroid in our solar system, which zips around the sun every 113 days. This artist's rendering shows the asteroid 2021 PH27 (top right) and Mercury (below) orbiting the sun.
Photos: Wonders of the universe
Meet the fastest asteroid in our solar system, which zips around the sun every 113 days. This artist's rendering shows the asteroid 2021 PH27 (top right) and Mercury (below) orbiting the sun.
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A ghostly set of X-ray rings were found around a black hole with a companion star. These rings are created by light echoes.
Photos: Wonders of the universe
A ghostly set of X-ray rings were found around a black hole with a companion star. These rings are created by light echoes.
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This image, taken with the Atacama Large Millimeter/submillimeter Array in Chile, shows the PDS 70 system 400 light-years away. This planetary system is still forming and still in the process of being formed. One of the planets in the system has a moon-forming disk around it.
Photos: Wonders of the universe
This image, taken with the Atacama Large Millimeter/submillimeter Array in Chile, shows the PDS 70 system 400 light-years away. This planetary system is still forming and still in the process of being formed. One of the planets