'Dark twin' of the Milky Way galaxy discovered

By Ashley Strickland, CNN

Updated 9:54 AM ET, Mon August 29, 2016

The Blue Ring Nebula is thought to be a never-before-seen phase that occurs after the merger of two stars. Debris flowing out from the merger was sliced by a disk around one of the stars, creating two cones of material glowing in ultraviolet light.
Photos: Wonders of the universe
The Blue Ring Nebula is thought to be a never-before-seen phase that occurs after the merger of two stars. Debris flowing out from the merger was sliced by a disk around one of the stars, creating two cones of material glowing in ultraviolet light.
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The red supergiant star Betelgeuse, in the constellation of Orion, experienced unprecedented dimming late in 2019. This image was taken in January using the European Southern Observatory's Very Large Telescope.
Photos: Wonders of the universe
The red supergiant star Betelgeuse, in the constellation of Orion, experienced unprecedented dimming late in 2019. This image was taken in January using the European Southern Observatory's Very Large Telescope.
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This is an infrared image of Apep, a Wolf-Rayet star binary system located 8,000 light-years from Earth.
Photos: Wonders of the universe
This is an infrared image of Apep, a Wolf-Rayet star binary system located 8,000 light-years from Earth.
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An artist's illustration, left, helps visualize the details of an unusual star system, GW Orionis, in the Orion constellation. The system's circumstellar disk is broken, resulting in misaligned rings around its three stars.
Photos: Wonders of the universe
An artist's illustration, left, helps visualize the details of an unusual star system, GW Orionis, in the Orion constellation. The system's circumstellar disk is broken, resulting in misaligned rings around its three stars.
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This is a simulation of two spiral black holes that merge and emit gravitational waves.
Photos: Wonders of the universe
This is a simulation of two spiral black holes that merge and emit gravitational waves.
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