HMS Conqueror wrote:
And I don't understand your desire to reduce everything to boolean right or wrong. It's more like probabilities. 2+2=4 is close enough 100%.
Please don't strawman. The argument above explicitly uses relative
certainty, and that was the entire point of comparison. So I've no idea where you're getting that from.
Either you don't know what "ad hoc" means or you're unaware of what's going on.
When it was observed that Cygnus X-1 was a compact anomalous X-ray source, they made detailed models of all the types of processes they could think of that it could be. Eventually, empirical evidence strongly favored 'blach ole'. It doesn't mean scientists have thought of everything or 'must' be right in some other way. What's important is that a lot of investigations produced a lot of reasonable alternatives, and they have been eliminated by observation. Note that it doesn't matter
if anyone actually expected X-ray sources of the type to be around. What matters is that the possibilities are genuinely investigated and alternatives eliminated. (If we're interested in black holes in general, there's broader and better evidence than just Cyg X-1, but that's another issue.)
DM is an ad hoc addition - no one knows what it is or thought it would be there before they realised observations couldn't be explained otherwise -, but black holes are a natural consequence of GR and were predicted long before they were (probably) discovered ... Comparison to non-flatness and Newton's Laws was made by someone earlier in the thread.
If we count personal expectations to gauge how surprising dark matter is, the idea that there may be some 'corpuscules' with total mass several orders of magnitude higher than stars and nebulae has been around for over a century
But that's not important. What is so is that the galactic rotation curve measures the enclosed mass directly by Newton's laws
. (Which you've admitted have high certainty, so there's a bit of inconsistency there in calling it as not directly observed.) So either
- There's mass there.
- The gravity we know doesn't apply at those scales.
Both of these categories have many proposals within them. Objects like the Bullet Cluster is that they actually rule out the various proposals in the second category.
You're misconstruing the 'dark matter problem'. It's not that we've no idea what it is. We have a myriad of ideas of what it is. Some of it based on physics we see in the lab, some on natural extensions of motivated by issues other than dark matter, and some based on natural extensions created before dark matter was even discovered. The problem is the mostly the opposite: there are far too many good ideas, and not enough empirical data to rule out enough of them.
HMS Conqueror wrote:
Dark matter is, what? I'm not sure I'd bet on it even at 50-50. Maybe you would, but would you bet on it at 999999-1?
I would, yes. And at more skewed odds than that besides. We know, with high certainty, that there is mass and that it is dark. It's nature
is highly uncertain, but that's not what you're arguing at all.