Scientists are about to kick off a brand-new search for dark matter, a mysterious substance that makes up about 85% of the universe. Their secret weapon? A highly sensitive dark matter detector located over a mile deep in the French Alps.
This advanced detector, built by an international team including researchers from Johns Hopkins University, aims to explore new possibilities for dark matter particles. It could either support the existence of certain candidates or rule some out entirely.
Danielle Norcini, a researcher with the team, highlights the challenge: “Dark matter is crucial to our understanding of the universe, yet our theories aren’t giving us clear results after decades of work. We need to broaden our search, and now we can.”
Why is dark matter so elusive? Even though it outweighs normal matter by a factor of five, we still don’t know much about it. Dark matter doesn’t interact with light, making it virtually invisible. However, it does affect gravity, which has helped scientists find that galaxies like the Milky Way are surrounded by vast halos of dark matter.
Current detectors primarily look for larger particles known as WIMPs (Weakly Interacting Massive Particles). But after 40 years of searching, no clear signals have emerged. This raises questions: What if dark matter is made of lighter particles that wouldn’t cause the heavier atoms in current detectors to react? Think of it like a bowling ball striking a ping-pong ball—an interaction that’s easy to miss.
The new detector uses silicon skipper charged-coupled devices (CCDs) that can detect smaller signals, specifically from single electrons circling an atomic nucleus. These detectors will be placed 1.2 miles underground, where cosmic rays and background noise are minimal. They’re well-shielded to prevent interference from natural events.
This initial prototype includes eight silicon skipper CCDs. The next phase will scale up to 208 sensors in a project called DAMIC-M. The larger size should increase the chances of capturing interactions that indicate the presence of lighter dark matter particles.
Research shows that spotting dark matter is akin to trying to hear a whisper in a noisy stadium. While no dark matter has been found yet, early results suggest the detector is functioning as intended. We may be on the verge of uncovering secrets that have eluded scientists for decades.
This research was published on August 13 in Physical Review Letters.
