Re: doesn't dark matter falsify general relativity?

2013-12-09 Thread LizR
I think I'll call it Relativi-stuck cosmology. On 9 December 2013 13:22, LizR lizj...@gmail.com wrote: I'm working on a theory that galaxies are held together by duct tape and superglue. It's proving a little tricky. Obviously the tape has to be arranged so the dark side is facing towards

Re: doesn't dark matter falsify general relativity?

2013-12-08 Thread Bruno Marchal
On 07 Dec 2013, at 23:58, John Mikes wrote: Telmo asked: Honest question: isn't dark matter a fancy name for failed predictions? I would not be so rude - just call it an ingenious way to save our scientific face in so far developed conventional science. Then it required 'dark energy'

Re: doesn't dark matter falsify general relativity?

2013-12-08 Thread LizR
I'm working on a theory that galaxies are held together by duct tape and superglue. It's proving a little tricky. Obviously the tape has to be arranged so the dark side is facing towards us... -- You received this message because you are subscribed to the Google Groups Everything List group.

Re: doesn't dark matter falsify general relativity?

2013-12-07 Thread John Clark
On Fri, Dec 6, 2013 at 5:28 PM, LizR lizj...@gmail.com wrote: If you were falling back first into a Black Hole things that were behind you would start to look as if they were ahead of you, and as you got very close to the event horizon all the light from the entire external universe would be

Re: doesn't dark matter falsify general relativity?

2013-12-07 Thread John Mikes
Telmo asked: *Honest question: isn't dark matter a fancy name for failed predictions?* *I would not be so rude * - just call it an ingenious way to save our scientific face in so far developed conventional science. Then it required 'dark energy' in the dark minds.And ALL had been justified by

Re: doesn't dark matter falsify general relativity?

2013-12-07 Thread LizR
On 8 December 2013 11:58, John Mikes jami...@gmail.com wrote: Telmo asked: *Honest question: isn't dark matter a fancy name for failed predictions?* *I would not be so rude * - just call it an ingenious way to save our scientific face in so far developed conventional science. Then it

Re: doesn't dark matter falsify general relativity?

2013-12-06 Thread John Clark
On Thu, Dec 5, 2013 at 8:11 PM, LizR lizj...@gmail.com wrote: Ah yes I've heard that the gravity at the event horizon can be as weak as you like with a suitably large hole - that you might not even realise you'd crossed it Yes. though surely you'd get some optical effects? If you were

Re: doesn't dark matter falsify general relativity?

2013-12-06 Thread LizR
It's a fascinating concept. What a shame it can't happen in the real world. On 7 December 2013 07:42, John Clark johnkcl...@gmail.com wrote: On Thu, Dec 5, 2013 at 8:11 PM, LizR lizj...@gmail.com wrote: Ah yes I've heard that the gravity at the event horizon can be as weak as you like with

Re: doesn't dark matter falsify general relativity?

2013-12-05 Thread John Clark
On Wed, Dec 4, 2013 at 8:12 PM, LizR lizj...@gmail.com wrote: The earliest reference I can find is 1783 by John Michell, he called them dark stars, however it had very different properties from a modern Black Hole. If I was far from one of Michell's Newtonian dark stars I could not see it,

Re: doesn't dark matter falsify general relativity?

2013-12-05 Thread LizR
On 6 December 2013 03:00, John Clark johnkcl...@gmail.com wrote: On Wed, Dec 4, 2013 at 8:12 PM, LizR lizj...@gmail.com wrote: The earliest reference I can find is 1783 by John Michell, he called them dark stars, however it had very different properties from a modern Black Hole. If I was

Re: doesn't dark matter falsify general relativity?

2013-12-04 Thread John Clark
On Mon, Dec 2, 2013 at 4:14 PM, LizR lizj...@gmail.com wrote: the 1919 eclipse data is actually somewhat equivocal, despite catapulting Einstein to fame. Back then the measurement was made right at the limit of what was possible with 1919 technology, since then it has been repeated many

Re: doesn't dark matter falsify general relativity?

2013-12-04 Thread LizR
On 5 December 2013 06:58, John Clark johnkcl...@gmail.com wrote: On Mon, Dec 2, 2013 at 4:14 PM, LizR lizj...@gmail.com wrote: the 1919 eclipse data is actually somewhat equivocal, despite catapulting Einstein to fame. Back then the measurement was made right at the limit of what was

Re: doesn't dark matter falsify general relativity?

2013-12-03 Thread LizR
On 3 December 2013 19:46, meekerdb meeke...@verizon.net wrote: We were both a little drunk, but he was serious. I asked if the blob of metal had been tracked in orbit? Zwicky said it was too small to track by radar. So then I asked how they knew it entered orbit. He said they knew because

Re: doesn't dark matter falsify general relativity?

2013-12-02 Thread LizR
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

Re: doesn't dark matter falsify general relativity?

2013-12-02 Thread meekerdb
On 12/2/2013 1:14 PM, LizR wrote: On 2 December 2013 20:14, meekerdb meeke...@verizon.net mailto:meeke...@verizon.net wrote: On 12/1/2013 7:35 PM, LizR wrote: On 2 December 2013 16:16, Richard Ruquist yann...@gmail.com mailto:yann...@gmail.com wrote: MOND is an

Re: doesn't dark matter falsify general relativity?

2013-12-02 Thread LizR
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

Re: doesn't dark matter falsify general relativity?

2013-12-02 Thread meekerdb
On 12/2/2013 10:19 PM, LizR wrote: On 3 December 2013 11:55, meekerdb meeke...@verizon.net mailto:meeke...@verizon.net wrote: On 12/2/2013 1:14 PM, LizR wrote: On 2 December 2013 20:14, meekerdb meeke...@verizon.net mailto:meeke...@verizon.net wrote: On 12/1/2013 7:35 PM,

Re: doesn't dark matter falsify general relativity?

2013-12-01 Thread LizR
On 30 November 2013 12:04, Telmo Menezes te...@telmomenezes.com wrote: Thanks for the explanations. Ok, I think I now understand why dark matter is the best hypothesis. It is, to date. Neverthless, you would have been quite correct had it been the anomaly in the orbit of Mercury that you

Re: doesn't dark matter falsify general relativity?

2013-12-01 Thread Richard Ruquist
Liz, There are 7 other repeatable observations explained by dark matter. From wiki-dark matter - 3.1 Galaxy rotation curveshttp://en.wikipedia.org/wiki/Dark_matter#Galaxy_rotation_curves - 3.2 Velocity dispersions of

Re: doesn't dark matter falsify general relativity?

2013-12-01 Thread LizR
Thanks, that's an impressive list. I'd be rather surprised if bolt-on extras to GR can explain all those. On 2 December 2013 12:43, Richard Ruquist yann...@gmail.com wrote: Liz, There are 7 other repeatable observations explained by dark matter. From wiki-dark matter - 3.1 Galaxy

Re: doesn't dark matter falsify general relativity?

2013-12-01 Thread Richard Ruquist
Can you explain what you mean by 'bolt-on extras to GR'? On Sun, Dec 1, 2013 at 7:18 PM, LizR lizj...@gmail.com wrote: Thanks, that's an impressive list. I'd be rather surprised if bolt-on extras to GR can explain all those. On 2 December 2013 12:43, Richard Ruquist yann...@gmail.com

Re: doesn't dark matter falsify general relativity?

2013-12-01 Thread LizR
Ad hoc modifications to our existing theories. Although it looks like it's actually bolt-on extras to Newtonian gravitation... http://en.wikipedia.org/wiki/MOND On 2 December 2013 14:33, Richard Ruquist yann...@gmail.com wrote: Can you explain what you mean by 'bolt-on extras to GR'? --

Re: doesn't dark matter falsify general relativity?

2013-12-01 Thread LizR
I should have said that by ad hoc I mean with no, or little, theoretical justification. That is, adjusting the threoy to fit the data, but with for no compelling theoretical justification. On 2 December 2013 15:42, LizR lizj...@gmail.com wrote: Ad hoc modifications to our existing theories.

Re: doesn't dark matter falsify general relativity?

2013-12-01 Thread Richard Ruquist
MOND is an alternative explanation that replaces Dark Matter by modifying gravity. Dark Matter results when gravity is not modified. (pure Newtonian) IMO John Moffat has a much better mod-gravity theory http://arxiv.org/pdf/gr-qc/0506021.pdf wiki-Moffat: He proposes a variable speed of

Re: doesn't dark matter falsify general relativity?

2013-12-01 Thread LizR
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

Re: doesn't dark matter falsify general relativity?

2013-12-01 Thread Richard Ruquist
Moffat even does away with renormalization. The acid test was to be the fine structure constant being time dependent. But that was not repeatable for a south hemisphere telescope whose name I forget. The two Keck Telescopes were built at Litton ITEK in Lexington, MA where I worked for a few

Re: doesn't dark matter falsify general relativity?

2013-12-01 Thread meekerdb
On 12/1/2013 7:35 PM, LizR wrote: On 2 December 2013 16:16, Richard Ruquist yann...@gmail.com mailto: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

Re: doesn't dark matter falsify general relativity?

2013-11-29 Thread Telmo Menezes
On Wed, Nov 27, 2013 at 5:03 PM, Jesse Mazer laserma...@gmail.com wrote: Dark matter behaves pretty convincingly like large clumps of matter that, aside from not interacting with normal matter via non-gravitational forces, obeys the same sort of dynamical laws as any other form of matter, see

Re: doesn't dark matter falsify general relativity?

2013-11-29 Thread Telmo Menezes
On Fri, Nov 29, 2013 at 4:57 AM, John Clark johnkcl...@gmail.com wrote: On Wed, Nov 27, 2013 at 9:07 AM, Telmo Menezes te...@telmomenezes.com wrote: if GR requires dark matter to work, and if we can't observe dark matter, doesn't this mean that GR is falsified? If Dark Matter really

Re: doesn't dark matter falsify general relativity?

2013-11-29 Thread John Clark
On Fri, Nov 29, 2013 at 6:18 AM, Telmo Menezes te...@telmomenezes.comwrote: why is it assumed that this phenomena is caused by some type of matter? [...] and I'm worrying too much about the word matter... Observations of the Bullet Cluster indicate that whatever this dark stuff is it has

Re: doesn't dark matter falsify general relativity?

2013-11-29 Thread Richard Ruquist
Does the Bullet cluster display any of the characteristics expected of a Dark-Matter-less galaxy such as a spinning galaxy blowing apart.? On Fri, Nov 29, 2013 at 3:18 PM, John Clark johnkcl...@gmail.com wrote: On Fri, Nov 29, 2013 at 6:18 AM, Telmo Menezes te...@telmomenezes.comwrote: why

Re: doesn't dark matter falsify general relativity?

2013-11-29 Thread John Clark
On Fri, Nov 29, 2013 at 3:31 PM, Richard Ruquist yann...@gmail.com wrote: Does the Bullet cluster display any of the characteristics expected of a Dark-Matter-less galaxy such as a spinning galaxy blowing apart.? For years people have tried to modify the law of gravitation so that it is

Re: doesn't dark matter falsify general relativity?

2013-11-29 Thread meekerdb
On 11/29/2013 3:18 AM, Telmo Menezes wrote: On Fri, Nov 29, 2013 at 4:57 AM, John Clark johnkcl...@gmail.com wrote: On Wed, Nov 27, 2013 at 9:07 AM, Telmo Menezes te...@telmomenezes.com wrote: if GR requires dark matter to work, and if we can't observe dark matter, doesn't this mean that GR

Re: doesn't dark matter falsify general relativity?

2013-11-29 Thread Richard Ruquist
My question has nothing to do with modyfying gravity On Fri, Nov 29, 2013 at 3:58 PM, John Clark johnkcl...@gmail.com wrote: On Fri, Nov 29, 2013 at 3:31 PM, Richard Ruquist yann...@gmail.comwrote: Does the Bullet cluster display any of the characteristics expected of a Dark-Matter-less

Re: doesn't dark matter falsify general relativity?

2013-11-29 Thread Telmo Menezes
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

Re: doesn't dark matter falsify general relativity?

2013-11-28 Thread John Clark
On Wed, Nov 27, 2013 at 9:07 AM, Telmo Menezes te...@telmomenezes.comwrote: if GR requires dark matter to work, and if we can't observe dark matter, doesn't this mean that GR is falsified? If Dark Matter really isn't there then that would indeed falsify General Relativity; but the theory that

Re: doesn't dark matter falsify general relativity?

2013-11-27 Thread Richard Ruquist
Dark Matter is required for GR to predict that galaxies do not fly apart Richard On Wed, Nov 27, 2013 at 7:40 AM, Telmo Menezes te...@telmomenezes.comwrote: Hi all, Honest question: isn't dark matter a fancy name for failed predictions? Cheers, Telmo. -- You received this message

Re: doesn't dark matter falsify general relativity?

2013-11-27 Thread Telmo Menezes
On Wed, Nov 27, 2013 at 3:04 PM, Richard Ruquist yann...@gmail.com wrote: Dark Matter is required for GR to predict that galaxies do not fly apart Richard Hi Richard, Thanks. I didn't express myself clearly. What I mean is: if GR requires dark matter to work, and if we can't observe dark

Re: doesn't dark matter falsify general relativity?

2013-11-27 Thread Richard Ruquist
Telmo Menezes te...@telmomenezes.com viahttp://support.google.com/mail/bin/answer.py?hl=enanswer=1311182ctx=mail googlegroups.com 9:07 AM (12 minutes ago) to everything-list On Wed, Nov 27, 2013 at 3:04 PM, Richard Ruquist yann...@gmail.com wrote: Dark Matter is required for GR to predict that

Re: doesn't dark matter falsify general relativity?

2013-11-27 Thread Jesse Mazer
Dark matter behaves pretty convincingly like large clumps of matter that, aside from not interacting with normal matter via non-gravitational forces, obeys the same sort of dynamical laws as any other form of matter, see the following for a good quick summary (note particularly the stuff about the

Re: doesn't dark matter falsify general relativity?

2013-11-27 Thread meekerdb
On 11/27/2013 4:40 AM, Telmo Menezes wrote: Hi all, Honest question: isn't dark matter a fancy name for failed predictions? No. Although it is dark it can be 'seen' by gravitational lensing and by its effect on the motion of luminous matter. Brent -- You received this message because you

Re: doesn't dark matter falsify general relativity?

2013-11-27 Thread LizR
On 28 November 2013 03:07, Telmo Menezes te...@telmomenezes.com wrote: Thanks. I didn't express myself clearly. What I mean is: if GR requires dark matter to work, and if we can't observe dark matter, doesn't this mean that GR is falsified? It seems to predict the existence of something that