On 3 December 2013 11:55, meekerdb <meeke...@verizon.net> wrote:
> On 12/2/2013 1:14 PM, LizR wrote:
> On 2 December 2013 20:14, meekerdb <meeke...@verizon.net> wrote:
>> On 12/1/2013 7:35 PM, LizR wrote:
>> On 2 December 2013 16:16, Richard Ruquist <yann...@gmail.com> 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.
> 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.
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