More to Explore
Einstein's Telescope: The Hunt for Dark Matter and Dark Energy in the Universe.
Evalyn Gates. W. W. Norton, 2009.

Approaches to Understanding Cosmic Acceleration.
Alessandra Silvestri and Mark Trodden in Reports on Progress in Physics, Vol. 72, No. 9, Paper No. 096901; Sept. 2009.

Modern Cosmology and the Building Blocks of the Universe.
Mark Trodden. Penn Alumni Weekend Lecture, May 15, 2010.

What's the Matter? The Search for Clues in Our Cold, Dark Universe.
Jonathan Feng. Pagels Memorial Public Lecture, July 14, 2010.

Dark Matter Candidates from Particle Physics and Methods of Detection.
Jonathan L. Feng in Annual Reviews of Astronomy and Astrophysics, Vol. 48, pages 495545; August 2010.
Solid evidence for the presence of dark matter
Dark matter can act as a giant lens
Silver Bullet
Is there any direct evidence for dark matter—WIMP or Super—WIMP based? The Bullet Cluster may have provided an answer. This is a pair of galaxy clusters that have collided. The collision had little effect on the stars; they passed quietly by each other. However, huge clouds of interstellar gas rammed into one another at 6 million mph, heat up to 100 million degrees celsius and fired out X-rays—(the red areas in the photo at left). It is the blue areas that are the mystery; these were detected in 2006 because of the gravitational lensing of the background stars. Despite the enormous gravitational mass, there is no interaction with anything else happening in the collision—this is very probably dark matter: unreactive particles oblivious to the firestorm around them.
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The colliding galaxies of the Bullet Cluster have provided direct evidence of dark matter.