Here's an interesting theory. https://astronomynow.com/2016/06/16/did-gravitational-wave-detector-find-dark-matter/ https://astronomynow.com/2016/06/16/did-grav

Here's an interesting theory. https://astronomynow.com/2016/06/16/did-gravitational-wave-detector-find-dark-matter/ https://astronomynow.com/2016/06/16/did-gravitational-wave-d... The gravitational waves we're detecting come from black holes, but the readings we have from LIGO suggest that they most likely come from 'primordial' black holes formed at the birth of the universe. If many of these black holes were formed they would be distributed much as MACHO theory predicts. 'Normal' black holes have very specific mass profiles so were generally ruled out as MACHOs, although obviously 'dark matter = black holes' has had a lot of consideration.