A black and purple background with bright white stars. A yellow circle in the middle of the image highlights a starless region, Cloud-9.

This image shows the location of Cloud-9, which is 14 million light-years from Earth.

Science: NASA, ESA, VLA, Gagandeep Anand (STScI), Alejandro Benitez-Llambay (University of Milano-Bicocca); Image Processing: Joseph DePasquale (STScI)/NASA

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Science: NASA, ESA, VLA, Gagandeep Anand (STScI), Alejandro Benitez-Llambay (University of Milano-Bicocca); Image Processing: Joseph DePasquale (STScI)/NASA

Cloud 9 is a failed galaxy. It’s a clump of dark matter, called a dark matter halo, that never formed stars.

But this failure could be the key to a mystery almost as old as the universe itself: dark matter.

Scientists don’t know what dark matter is, but Cloud 9 could offer new clues. Three researchers weigh in on this new discovery and why it could be a missing piece to the story on how the universe formed.

Check out our episode with astrophysicist Jorge Moreno on the mysterious Great Attractor and our summer series on space. 

Have a scientific question you want us to answer? Email us at shortwave@npr.org.

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This episode was produced by Rachel Carlson. It was edited by Rebecca Ramirez. Tyler Jones checked the facts. The audio engineer was Robert Rodriguez.Â