3 ms·

I don't think your description is correct. The situation is we have a reasonably exact theory that assumes that most of the matter in the universe is neutral in

I don't think your description is correct. The situation is we have a reasonably exact theory that assumes that most of the matter in the universe is neutral in the sense of only interacting gravitationally. But that interaction can be calculated quite readily in certain circumstances - for example, we can observe the "dark matter halo" in galaxies through gravitational lensing. This is the dominant theory, it's not in contradiction with observations, it's just, a little weird. Why things are like that is the mystery but that's it for dark matter. Sure, this stuff is invisible. So is electricity but we deal with that. (Dark Energy I don't enough to talk about).

gpderetta 7y ago
> Sure, this stuff is invisible. So is electricity but we deal with that. Good description but bad example :). Photons are literally excitations of the electromagnetic field. You could say that everything except electricity [1] is invisible. Neutrinos are a better example as a known form of dark matter. /Pedantic [1] yes yes electricity is just one phenomenon of the electromagnetic field. I'm just differently wrong.
- Beltiras 7y ago
  Worse yet: electrons passing down into ground state will emit a photon. In essence, all we see ever is direct electrical activity.
  - perl4ever 7y ago
    That isn't a counter to the claim that electrical activity we don't see is something we take for granted that happens all the time around us.
- perl4ever 7y ago
  Many photons are invisible. The point is that not that dark matter is similar to other things in general, but that it's similar to a large list of things we take for granted in that you can't see it with the unaided eye and it would have sounded like woo a few hundred years ago.
superqd 7y ago
I think it is a more than a little weird, as we find that over different scales our ability to predict loses its precision. We attribute this to an unknown something, that is sometimes referred to as "dark matter", but in reality is something we have not directly observed. Dark matter is essentially a placeholder for our ignorance, but with a little bit of assumption sauce thrown in.

gpderetta 7y ago

> Sure, this stuff is invisible. So is electricity but we deal with that. Good description but bad example :). Photons are literally excitations of the electromagnetic field. You could say that everything except electricity [1] is invisible. Neutrinos are a better example as a known form of dark matter. /Pedantic [1] yes yes electricity is just one phenomenon of the electromagnetic field. I'm just differently wrong.

Beltiras 7y ago
Worse yet: electrons passing down into ground state will emit a photon. In essence, all we see ever is direct electrical activity.
- perl4ever 7y ago
  That isn't a counter to the claim that electrical activity we don't see is something we take for granted that happens all the time around us.
perl4ever 7y ago
Many photons are invisible. The point is that not that dark matter is similar to other things in general, but that it's similar to a large list of things we take for granted in that you can't see it with the unaided eye and it would have sounded like woo a few hundred years ago.

superqd 7y ago

I think it is a more than a little weird, as we find that over different scales our ability to predict loses its precision. We attribute this to an unknown something, that is sometimes referred to as "dark matter", but in reality is something we have not directly observed. Dark matter is essentially a placeholder for our ignorance, but with a little bit of assumption sauce thrown in.