These oddball galaxies are missing their dark matter - National Geographic

A pair of dim, puffy galaxies are devoid of this key cosmic ingredient. Now astronomers using the Hubble Space Telescope say they may know why.

In the cosmic equivalent of a total knock-out punch, two galaxies collided some eight billion years ago and kicked the gas out of each other. Thats the latest explanation for a cosmic mystery thats … [+8608 chars]

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