> we can map dark matter's location

this has always felt circular to me -- someone drops an astronomy paper like 'we found a galaxy with no dark matter' and I wish someone would rewrite it as 'dear non physicist, here are ten critical takes you just thought of and why we discarded each'

this is mostly a knock on my own knowledge, and slightly a knock on pop science press, but I don't know the steps between 'mass as inferred from light doesn't explain galactic rotation curves' and '80% of mass is ghosts'