> 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 <[email protected]> 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 [email protected]. To post to this group, send email to [email protected]. Visit this group at http://groups.google.com/group/everything-list. For more options, visit https://groups.google.com/groups/opt_out.
