Detect Dark Matter's Mark from Your Backyard

If you’re wondering what dark matter is, you’re not alone. Astronomers don’t know. But they’ve determined that this invisible material must be far more abundant than the stars and nebulas that they can see. They’ve surmised as much from observing the gravitational effects of all this perplexing dark stuff, launching a decades-long campaign to understand its nature.

I recently learned that it is possible to sense the presence of dark matter using a small radio telescope such as the Discovery Dish covered in these pages last year. The trick is to know what observations to collect and how to analyze them. I’ll sketch that out below, but first let me describe the homemade radio telescope I put together for this project.