Sterile neutrino

Okay, so you know how everything is made up of tiny little things called atoms? Well, inside those atoms there are these even tinier things called subatomic particles. One of these particles is called a neutrino.

A neutrino is a type of particle that hardly ever interacts with anything. It's kind of like a ghost particle! Scientists have discovered three types of neutrinos: the electron neutrino, the muon neutrino, and the tau neutrino.

But there might be a fourth type of neutrino called a sterile neutrino. Sterile neutrinos are different from the other three types because they don't interact with matter at all! That's why they're called "sterile" - they don't create any reactions or changes in the things they pass through.

Scientists think that sterile neutrinos might help explain some weird things they've seen when they look at the universe. For example, galaxies seem to have less matter in them than they should according to our current theories. Some scientists think that sterile neutrinos might be the missing matter - they could be all around us but we just can't see or feel them.

So, even though sterile neutrinos might not sound as exciting as other particles, they could actually be really important in helping us understand the universe!