I’d love to know what this dark matter stuff is, and you know that physicists want to know even more.
So, why does dark matter, matter, anyway? Well, this stuff makes up a huge chunk of the Universe, and we want to know what the Universe is made of. If it turns out to be an elementary particle that isn’t part of the Standard Model of particle physics, then that means the Standard Model is wrong, and we’ve got some cool new physics! If, on the other hand, it somehow turns out to be that our understanding of gravity is fundamentally flawed, we still get new physics. And new physics is always exciting! Either way, it’s about learning about our Universe. Think about it: right now, the stuff we know and are familiar with accounts for just 5% of the Universe’s contents. Imagine what ticking off another 25% of the Universe would mean. Don’t know? Neither do I, but that’s what’s so exciting about it! My bet is that it’s a new particle, and the Standard Model is wrong. Maybe it’ll be SIDM, maybe WIMPs, or Kaluza-Klein dark matter. Maybe it’ll be several types of dark matter, with new forces in the dark sector; I mean, why shouldn’t it be, when the visible sector is a particle zoo? Whatever it turns out to be, unraveling this mystery will be a ground-smashing achievement in the world of physics.
That comes from a pretty good summary of many of the current models for dark matter (well, I thought it was an informative summary, but I’m a biologist, so what do I know?). Some day I’m going to need a physicist to sit down with me over a beer and explain this stuff in little words.