The more you learn about cosmology, the weirder it gets.
When it comes to dark matter, there is far more unknown than known. In fact, as NASA eloquently puts it, “we are much more certain what dark matter is not than we are what it is”.
To begin with, astronomers know it is utterly dark, unlike the stars and planets we know. It’s also not like dark clouds of ordinary matter formed up of particles known as baryons.
Dark matter isn’t antimatter either because we don’t witness the distinctive gamma rays created when antimatter collides with the matter. Finally, based on the number of gravitational lenses observed, we can rule out enormous galaxy-sized black holes, too.
As you can tell from this brief description, dark matter is complicated. In this Veritasium video, engineer and YouTuber Derek Muller goes on a tour of the southern hemisphere’s first dark matter underground physics laboratory to see the efforts scientists are undertaking to help understand dark matter.