Question: So if dark matter is balancing out the matter we know does that mean it is a negative force? And does that mean it has a different looking atom?

Sam Geen answered on 9 Nov 2020:

Dark matter and “regular” matter like atoms both pull with gravity. The only difference with dark matter is that it doesn’t interact much or at all with light, so you can’t see it and it doesn’t collide much or at all.

Dark energy, however, pulls the universe apart, or at least our current theories and observations tell us it does. We don’t know what Dark Energy really is, only that something is pulling the universe apart.

We don’t yet know what dark matter is. My friend Bradley Kavanagh who works on dark matter says: “It could be a new particle that we haven’t discovered yet, which doesn’t interact with light in the way ordinary matter does. That is, it can only interact very weakly with other particle, so they’re sometimes called Weakly Interacting Massive Particles (WIMPs). Another possibility is a particle called the axion, which we expect to be around because it helps us understand some unusual properties of protons and neutrons. Even weirder would be small black holes, about as heavy as an asteroid but much smaller, which could be formed in the very early Universe.”