Posted on 01/09/2007 12:12:54 AM PST by SunkenCiv
The poster child for dark matter, which got a lot of attention last summer, is the Bullet Cluster of galaxies... What's less well known is that the smaller of the two colliding clusters is a cluster in a hurry, zipping along at 4700 kilometers per second... Farrar... and her graduate student Rachael Rosen estimated a few months ago that gravity should have accelerated the cluster to maybe 3000 km/s. Even if the cluster had an improbable combination of elongated shape, high initial velocity, and special viewing geometry, it should move no faster than 3400 km/s. Farrar concluded that some new force must be helping to accelerate it. Such a force might also explain a number of other discrepancies that astronomers have found. For instance, the universe contains more galaxy superclusters than standard dark-matter models predict. A new force would grease the wheels of supercluster formation. It would also have telltale effects within our own galaxy... What the putative force might be, no one knows, any more than anyone knows what dark matter is to begin with.
(Excerpt) Read more at blog.sciam.com ...
bttt
- - - cut - - -
insert star wars joke here.
- - - cut - - -
"...otherwise the Light Side would it be."
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.
