Now, call me crazy, but I’m pretty sure the entire point of a telescope is to look up, right? I mean, up relative to your spot on the Earth, obviously. Yes, the typical purpose of a telescope is to look at stuff that’s really far away like stars and planets. But, at least theoretically, a telescope could be used to observe something up close that’s really tiny. “Like what,” you ask? Well, how about a neutrino particle?
Neutrino particles are these teeny-tiny dudes that zip around space seemingly at random. Since they don’t really work the same way as solid matter does, they can phase through anything like a ghost. It’s for this reason, as well as the fact that radiation disrupts them, that they’re really tricky to spot. This is where KM3NeT comes in.
KM3NeT, AKA the Cubic Kilometre Neutrino Telescope, is a sensor array currently being built at the bottom of the ocean, the purpose of which is to scan the Earth’s crust for signs of neutrinos. The Earth is big, relatively speaking, so if we want to catch a neutrino flying by without worrying about interference from ambient radiation, its base levels are a great place to stick a lookout.
There’s no projected date on when KM3NeT will be completely, unfortunately, but tests have been running at the same time as construction, so hopefully, once it’s complete, the real search can hit the ground running. Or swimming, I guess.