I’ve never seen so many scientists excited over so much nothing.
Well, almost nothing, to be precise.
Neutrinos, you see, have almost zero mass. In fact, up until a little while ago, scientists didn’t think they had any mass at all. Chances are if you’re reading this, you’ve already heard of these particles before and may even know what they are. But just in case, here’s a short primer.
There are three types of neutrinos and they are produced in atomic reactions. All of them are nearly massless and, as a result, all of them pass through “solid” material by missing the enormous spaces between the nuclei of atoms.
If a nucleus was a basketball at the center of a football field, the electrons would be swooping around the outskirts of the stadium.
For example, when an atom splits apart or when two atoms are smashed together into one, neutrinos can result. Or when sometimes a proton spontaneously changes into a neutron, neutrinos are often sprung forth to balance the energy shift. Particle accelerators often create them by smashing things together.
There are two main sources for the billions of neutrinos passing through your fingernail every second of every day—the sun and the atmosphere. The sun creates them during its fusion processes while atomic particles crashing into the atmosphere from space are constantly creating others. Among this giant background noise, it’s nearly impossible to detect neutrinos coming in from any other source in space.
I did say nearly.
Now, for the first time, scientists have managed to detect 28 neutrinos with such high energies that they have to have originated from some spectacular source—a supernova, a black hole, pulsars, and star foundries, for example.
And they did it with ice.
Not every neutrino passes straight through the Earth. Every now and then, one will interact with an atom. When a neutrino strikes a hydrogen atom, for example, which is just a proton with a single orbiting electron, it gets nudged causing it to release a flash of blue light called Chekov radiation.
Scientists created a giant ice cube beneath the North Pole with extremely sensitive light detectors embedded within to detect these flashes of light. How big is it? An entire square kilometer. That’s a lot of H2O; enough to fill about a million swimming pools. Based on the light’s intensity, the researchers could determine the energy with which the neutrino struck the atom.
During the course of two years, the detector managed to snag a couple dozen neutrinos. But it’s a huge success as that’s actually more than scientists were expecting to be able to see. With this new ability, astrophysicists will have a window through which to study some of the biggest, badass astronomical phenomena in the universe.