[unlearner]

"Dark matter [is] invisible, yet undoubtedly there"

You can count me as a doubter. Dark matter is a contrivance to fill the gaps in otherwise sensible theories.

I find it much easier to believe the fine structure constant and light velocity have changed over the history of the universe.

To me this is a more rational explanation of measurements that seem to indicate an accelerating universe and gravity with no apparent matter.

[gcruse]

You can count me as a doubter. Dark matter is a contrivance to fill the gaps in otherwise sensible theories.

I understand.  It's the contrivance of a supernatural, also invisible, man in the sky to fill in the gaps of otherwise sensible theories that made an atheist out of me. However, there is much more evidence for dark matter than deity.