The disagreement inolves the existence of Dark Matter.
The prevailing theory among physicists was that there are 3 indications that dark matter exists
Rotation Curves
Zwicky estimate of galaxy cluster binding
Cosmological bounds
Erik Verlinde, a Dutch theoretical physicist at the University of Amsterdam doesn't believe it exists and it has to do with the nature of gravity and our understanding of it which is not very good at best. Some others agree with him or are beginning to at least look at the possibility he may be right.
Even among brilliant thinkers there is always disagreement. The lone voice may be right or could be a crackpot. The current thinking may be spot on or all wrong. That is how we make progress. One onion layer at a time being peeled off by those who do not accept what others do because it doesn't make sense to them.
I think it's exciting. Will we ever find out which camp is right? I dunno. But it's a welcome relief from the political crap that is consuming us. Look to the skies. Look to the stars and beyond. Maybe there are answers out there. If we don't look we can never know.
