> All we know is that there are places where spacetime curves in ways our theories didn’t predict from the matter we observe
I think we can say more than that. For observations to be compatible with the hypothesis that dark matter is particles or fields that interact gravitationally but not electromagnetically or strongly enough with itself to cause too much friction with itself,
It doesn’t just need to be the case that “if there was such matter at these locations at this time, then the gravitational effects on what we do see would be like what we see”. There is an additional major constraint: the dynamics of the dark matter particles/field(s) have to work with the distribution we see.
Like, if we have two regions which each have some normal matter and some dark matter, and they ran into one another, the dark matter shouldn’t be slowed by the friction in the way the visible matter is,
Etc. etc.
Like, in order for the observations to be compatible with the hypothesis that dark matter particles are the thing, the distribution of “where the dark matter would have to be in order to explain the gravitational effects” would have to be a distribution that would make sense for it to be in, under the assumption that it is dark matter particles.
I think we can say more than that. For observations to be compatible with the hypothesis that dark matter is particles or fields that interact gravitationally but not electromagnetically or strongly enough with itself to cause too much friction with itself,
It doesn’t just need to be the case that “if there was such matter at these locations at this time, then the gravitational effects on what we do see would be like what we see”. There is an additional major constraint: the dynamics of the dark matter particles/field(s) have to work with the distribution we see.
Like, if we have two regions which each have some normal matter and some dark matter, and they ran into one another, the dark matter shouldn’t be slowed by the friction in the way the visible matter is,
Etc. etc.
Like, in order for the observations to be compatible with the hypothesis that dark matter particles are the thing, the distribution of “where the dark matter would have to be in order to explain the gravitational effects” would have to be a distribution that would make sense for it to be in, under the assumption that it is dark matter particles.