Naming of Uranus?
I've always wondered if the naming of Uranus was a bit 'tongue in cheek'
:)
It seems you don't need a disk to thumb your nose at celestial mechanics - if you're big enough to be a galaxy. Recent investigations of the velocities of stars in dwarf galaxies have reinforced the need for explanatory dark matter to account for their motion, according to Professor Mario Mateo and and Dr Matthew Walker of the …
"Mateo, on the other hand, prefers a model of dark matter that modifies the force of gravity itself according to the accelerations within the system".
actually, modified newtonian dynamics isnt a dark matter model, in fact it's original author Mordehai Milgrom came up with it because the dark matter models have too many weaknesses (read: gaping holes) that can be adequately explained by a modification to F=ma.
also, the fact that MOND explains the rotation curves of dwarf galaxies quite well is already fairly well documented, just google for
"MOND and Mass Discrepancies in Tidal Dwarf Galaxies"
which is a paper by the author of MOND.
</science>
and finally.... a 2 page article, and not a single mention of paris hilton, whats going on?
1/ THE LINK IN THIS ARTICLE to SPACEDAILY.COM IS 404
2/ Some of us like links to arXiv papers, so we can read them. We certainly expect the authors have read them. For the record, I think, the paper in question is:
http://arxiv.org/abs/0708.1327
3/ This article waffles where it should be explaining. The first page is not too bad, but the second is appalling.
I'd not heard of MOND before, and I had to go read about it on on wikipedia - just to make sense of this article. I still don't understand what the author means when he says "The outre model of spiral galaxies as cosmic Faraday motors, espoused by some theorists,". Which theory is this? (It's not the "mainstream" CDM, surely?) Which theorists are espousing it?
Dark matter is fascinating. There are lots of tantalisingly off-beat theories (try this http://arxiv.org/abs/hep-ph/0612286v2), and its a constantly shifting field where new evidence is accumulating all the time. This article doesn't come close to doing it--or science--justice. Please, no more articles like this.
Galaxies don't move like they should according to our laws of physics because theres something wrong or missing in our body of theories. If they did, they would resembe giant ring systems.
Sooner or later we'll suss this one out. I've never been convinced by the whole dark matter thing anyway, I mean really. Its like a flat Earth theory.
I have always thought that the idea of Dark Matter/Energy is just a black box construct for a system we do not understand. It allows us to explain something that we can see but do not know how it works.
I still believe that there is more to gravity than we have discovered. The pioneer probes slowing faster than predicted are one example of this. We don’t know why. It just is. For all we know there could be other forces of gravity - much like the strong and weak atomic forces - that are acting on objects far out from a gravity well. Truth is we won’t be able to figure this out until we can get a firm grasp of what gravity is and how it works.