Trying to figure out how to observe things takes up a shocking amount of time. Sure, you can go out, look up, and do some science – especially variable star science – with your eyeballs. It turns out that, for every easy thing to observe, there are a dozen things trying not to be observed. Things like neutrinos.
These antisocial particles are generated in a lot of different nuclear processes, ranging from fission to fusion to everyday radioactive decay, and high-speed collisions. These particles generally pass through us by the thousands without anything happening, but occasionally, a neutrino with just the right energy on just the right path can collide with a particle in water and give off a flash of light.
Our human bodies are far too small for this to be a concern, but scientists can leverage giant regions of water or ice to look for these flashes, and right now, there are new detectors being built by stringing sensors in grids in the Mediterranean, in Russia’s Lake Baikal, and off the western coast of Canada. With this global network of detectors, it’s hoped that it will become possible to figure out what kinds of phenomena are producing neutrinos.
Currently, a massive detector named IceCube is looking for flashes in Antarctic ice. Two of these neutrinos are traced back to events associated with supermassive black holes in galaxy cores. Since we thought these neutrinos came from star-forming regions and supernovae, these discoveries highlight the need for more information. Now, thanks to the Earth having so much water and the ability of scientists to string sensors together and dangle them in that water, the detailed information we want should be coming.