Ghost particles. That's the name numerous physicists give to neutrinos, the nearly weightless subatomic particles that are omnipresent, everywhere, at every moment. Their presence is typically undetectable, and it often requires experiments as large as swimming pools or even bigger to capture them. Yet they are vital components in the particle physics enigma that explains everything we observe in the universe. And they're incredibly odd. Here are some of the peculiar things physicists have discovered about neutrinos.