Yeah, “dark matter” really bothers me. Which seems more likely?
That there are massive quantities of invisible matter in the universe that only interacts via gravitation? And happens to be spread around in about the same density distribution as all the regular matter?
Or that our estimate for the value of the universal gravitational constant is either off a little bit or not quite as constant as we think?
The former sounds a little too much like an invisible dragon to me. Which doesn’t make it impossible, but exotic, nigh-undetectable forms of matter just doesn’t seem as plausible as observation error to me.
That there are massive quantities of invisible matter in the universe that only interacts via gravitation? And happens to be spread around in about the same density distribution as all the regular matter?
Your second sentence is a pretty straightforward consequence of your first.
That is a reasonable possibility, although if it only interacts with normal matter via gravitation, which is relatively weak, then I’d expect to see its dispersal lag significantly behind, say, a supernova. And that lag would seem likely to result in such events skewing the distribution over time.
Unless we’re also going to postulate that dark matter has its own energy, chemistry, and physics which resemble those of normal matter so closely that such things happen in both realms at the same time...
Measurement error and/or gravity having some kind of propagation properties we haven’t worked out yet still seems like a contender for the explanation, unless they have, indeed found pockets in the universe with differing amounts of excess gravitation that match what one would expect in the wake of fast-moving objects. I haven’t seen any reports about that myself, but I can’t say I’m an insider on the latest research or anything.
Yeah, “dark matter” really bothers me. Which seems more likely?
That there are massive quantities of invisible matter in the universe that only interacts via gravitation? And happens to be spread around in about the same density distribution as all the regular matter?
Or that our estimate for the value of the universal gravitational constant is either off a little bit or not quite as constant as we think?
The former sounds a little too much like an invisible dragon to me. Which doesn’t make it impossible, but exotic, nigh-undetectable forms of matter just doesn’t seem as plausible as observation error to me.
Your second sentence is a pretty straightforward consequence of your first.
That is a reasonable possibility, although if it only interacts with normal matter via gravitation, which is relatively weak, then I’d expect to see its dispersal lag significantly behind, say, a supernova. And that lag would seem likely to result in such events skewing the distribution over time.
Unless we’re also going to postulate that dark matter has its own energy, chemistry, and physics which resemble those of normal matter so closely that such things happen in both realms at the same time...
Measurement error and/or gravity having some kind of propagation properties we haven’t worked out yet still seems like a contender for the explanation, unless they have, indeed found pockets in the universe with differing amounts of excess gravitation that match what one would expect in the wake of fast-moving objects. I haven’t seen any reports about that myself, but I can’t say I’m an insider on the latest research or anything.
The whole point of dark matter is to hold galaxies together through gravity. And it is posited as having exotic properties apart from gravity.