About this episode
The episode discusses the Coma galaxy cluster and the concept of dark matter as discovered by Fritz Zwicky.
The Coma galaxy cluster is like a cosmic iceberg. What you see is impressive. But what you don’t see is even more impressive. The cluster is centered more than 300 million light-years away, and it spans 25 million light-years. It contains thousands of individual galaxies. Many of them are far bigger and heavier than our own galaxy, the Milky Way. But in the 1930s, German astronomer Fritz Zwicky found something odd. He measured the motions of individual galaxies within the cluster. They were zipping along much too fast to be held in check by the gravity of the visible galaxies – they should all fly away from each other. Zwicky concluded that something else was acting as a sort of gravitational “glue.” He called it dark matter – matter that couldn’t be seen, but that exerted a gravitational pull on the visible matter around it. It took decades to confirm that finding. And even today, we don’t know what dark matter really is. The leading idea says it’s some type of subatomic particle. But despite many years of searching, no such particle has been found. All we know for sure is that dark matter accounts for about 85 percent of all the…
People in this episode
Host: Damond Benningfield
Topics covered
- Coma galaxy cluster
- dark matter
- Fritz Zwicky
- cosmic iceberg
- astronomy
Keywords
- galaxies
- gravity
- subatomic particles
- universe
Mentioned in this episode
Places: Coma, the Milky Way, The Coma Cluster, Coma Berenices, Arcturus, Bootes
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