On 3 December 2013 11:55, meekerdb <[email protected]> wrote: > On 12/2/2013 1:14 PM, LizR wrote: > > On 2 December 2013 20:14, meekerdb <[email protected]> wrote: > >> On 12/1/2013 7:35 PM, LizR wrote: >> >> On 2 December 2013 16:16, Richard Ruquist <[email protected]> wrote: >> >>> MOND is an alternative explanation that replaces Dark Matter by >>> modifying gravity. >>> >> >> Yes (hence the flippant remark about bolt on extras) >> >> >>> Dark Matter results when gravity is not modified. (pure Newtonian) >>> >> >> Or rather Einsteinian, I don't think Newtonian gravity predicts >> gravitational lensing? >> >> >> Sure it does, but only half as strong as GR. >> >> Ah yes, that's right. I believe that's why the 1919 eclipse data is > actually somewhat equivocal, despite catapulting Einstein to fame. (And > someone predicted black holes way before Einstein, too, on the basis of > Newtonian gravity and the measurement of c - although without realising the > full implications ... Mitchell???). > > Mind you, I think my correction above is still pertinent - that is, it's > still truer to say that "dark matter is what results when gravity is not > modified (pure *Einsteinian*)". > > > Dark matter would be implied by the same observations even assuming > Newtonian gravity. Just the amount would be different. I don't know if > Fritz Zwicky even used relativistic calculations of rotation curves of > galaxies to infer dark matter - it wouldn't have been necessary since the > motions are not that fast. >
OK. > > Incidentally I met Zwicky at a party once and he regalled me with the > story of how he and a NACA team had actually beaten the Russians into space > by launching an artificial satellite *before* Sputnik. When I expressed > surprise that I had never heard of this satellite, he explained that it was > launched from a B-50 flying at 50kft over the equator using a two stage > rocket. When the second stage reached it's apogee, it fired a shaped > charge which sent a molten mass of metal into orbit around the Earth. > > Seriously?! -- 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.
