Ready for a mind-boggling idea?
of the universe may not be made of the same type of matter as the
Earth. We infer from gravitational effects the presence of this dark
matter, a type of matter that we cannot see. There is strong evidence
that it might not be made up of protons, neutrons, and electrons.
What is dark matter, then? We don't know. Perhaps it is composed of
neutrinos, or even more exotic forms of matter, like neutralinos, one
of the theoretical supersymmetric particles.