ASTROPHYSICS: STAR FORMATION HISTORY OF THE UNIVERSE ASTROPHYSICS STAR FORMATION HISTORY OF THE UNIVERSE Another 23 percent isdark matter, an extraordinary and unknown material that is not seen on Earth. http://scienceweek.com/2005/sc050121-1.htm
Extractions: 1) More than 9000 billion billion (9 Î 10^(21)) stars have been formed in the observable Universe since it began 13.7 billion years ago. Despite the apparent wealth of stars in the sky, current cosmological models suggest that the Universe was quite dark for much of its first billion years. During these dark ages, the Universe contained clouds of gas and dark matter, but little else the first stars did not form until several hundred million years had passed. Once the cosmic star-making machinery got going it seems to have churned out stars at a prodigious rate. 4) Despite the admittedly mysterious circumstances, we know quite well in broad outline how the Universe formed the structures we see. Observations of the cosmic microwave background, which dates to when the Universe was only 300,000 years old, show that the Universe was not quite uniform in its early phases. These observations have been made with a number of ground-, balloon-and satellite-based experiments, most famously with the Cosmic Background Explorer in the early 1990s, and now at higher resolution with the Wilkinson Microwave Anisotropy Probe. These experiments revealed small irregularities in the density of the early Universe. The irregularities also happened to be unstable: Denser-than-average regions had slightly stronger gravity, and so pulled matter in to form "clumps." In this way dense objects formed over time through a combination of gentle accretion and the merger of smaller units.
Particle Astrophysics Seminars « Events Particle/Astrophysics Seminars, Spring 2005 Technique for WIMP dark matterdetection using pulseshape discrimination in noble liquids http://www.phys.cwru.edu/events/pa.php?abstract=11
Astrophysics And Space Science links to pages about astrophysics and space. A presentation of darkmatter particles, and the search for them, by the Particle Astrophysics http://www.hypography.com/links.cfm?id=7070
