> For years people have tried to modify the law of gravitation so that it is > consistent with what we see with our telescopes but it just doesn't work. If > you observe the Bullet Cluster what you see is 2 clusters colliding and the > regular matter that we can see staying in the center just as we'd expect > regular matter to do and the Dark Matter (detected by gravitational lensing) > remained spread out just as you'd expect Dark Matter to do. There is no way > modifying gravity can explain that. > > And in addition, if you tinker with gravity so that galaxies like our own > Milky Way hold together and behave as they should then galactic clusters > like the Local group don't behave as we see them do. And if you tinker with > gravity in another way so that galactic clusters behave as they do in our > telescopes then individual galaxies don't. But if you invoke Dark Matter > then everything comes out fine. > > John K Clark
On Fri, Nov 29, 2013 at 10:26 PM, meekerdb <meeke...@verizon.net> wrote: > First, that isn't just assumed. Other theories to explain it have been put > forward, e.g. modifications of GR. But so far they have all been > invalidated by observations, whereas the hypothesis that it is some kind of > matter that interacts only (or almost only) via gravity has survived an > increasing variety of observations. > > >> As far >> as I understand, QM hasn't been reconciled with GR gravity. Isn't this >> + dark matter a sign that there's something fundamental we don't >> understand yet? > > > There's certainly somethings we don't understand yet. Whether dark matter > is 'fundamental', in the sense that QM and GR are fundamentally in conflict, > is possible but not supported by any data yet. > > Brent John and Brent, Thanks for the explanations. Ok, I think I now understand why dark matter is the best hypothesis. Cheers Telmo. -- You received this message because you are subscribed to the Google Groups "Everything List" group. To unsubscribe from this group and stop receiving emails from it, send an email to everything-list+unsubscr...@googlegroups.com. To post to this group, send email to everything-list@googlegroups.com. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
