Have you ever looked up at the night sky and wondered what you’re not seeing? The skies may be full of invisible “boson stars” that are made of an exotic form of matter that does not shine.
We strongly suspect that the universe is full of dark matter, which makes up around 25% of all the mass and energy in the cosmos. But while circumstantial evidence abounds and we believe that dark matter is some sort of undiscovered particle, we don’t have any direct evidence of such a particle.