Quote:
Originally Posted by renormalised
Too early in the morning to discuss this!!!  
Both hypotheses have a long way to go before anything definitive can be said, either way.
(Notice I didn't call them theories) |
Hmm .. (I've had a few coffees now) ..
I think its fair to say that DM is a hypothesis supported by indirect observational evidence (a bit like the Oort Cloud) and it may also be fair to say, it is also inferred from other theoretical models and predictions.
But MOND is a direct variant of Newton's
Law of Universal Gravitation. Newtonian gravitation is an approximation for GR Theory, and GR Theory, will/has been used in the establishment of a Unified Field Theory.
Law=> GR Theory => Grand Unified Theory. (I guess 'the apple', was an initial observation upon which an hypothesis was formed leading ultimately, to a Law
.. it may also have been a myth
)
What these guys are claiming is that MOND Theory has now predicted the mass and rotation velocities of a sample of 47 galaxies and found a good 'fit' or 'agreement' between the observations and the predictions. But DM cosmology works well on the scales of galaxy cluster and up - which is where the proportion of DM in the obs. universe 'swamps' ordinary matter.
So long as this remains the case, DM is here to stay, (firmly, as a hypothesis).. yet again.
Comments welcome.
Cheers