Post #2984364

The *primary* thing we have detected is an attractive force within galaxies. Whether that's otherwise-undetectable particles or a mistake in how we calculate gravity or something else, we *definitely* know it's that there is more attractive force holding galaxies together than there should be based on detectable matter and general relativity. Simply put: galaxies rotate too fast. Much, *much* too fast. That can't be caused by repulsion between galaxies. Only by the stars within a galaxy being pulled towards the centre of that galaxy my than we would expect. Similar to how you have to spin faster to hold a big bucket of water horizontal without spilling than to hold a small bucket of water.