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Bullet Cluster
A purple haze shows dark matter flanking the “Bullet Cluster.” Image Credit: X-ray: NASA/CXC/M.Markevitch et al. Optical: NASA/STScI; Magellan/U.Arizona/D.Clowe et al. Lensing Map: NASA/STScI; ESO WFI; Magellan/U.Arizona/D.Clowe et al The amount of matter, or “mass,” in a galaxy is made up mostly of the gas that surrounds it. Stars, planets, moons and other objects count…
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Radiactive Decay
Unit Circle Complex numbers can be identified with points in the Euclidean plane, namely the number a + bi is identified with the point (a, b). Under this identification, the unit circle is a group under multiplication, called the circle group. This group has important applications in mathematics and science. See here. Just briefly showing…
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Purpose of the Compton Lecture Series
April 8The 63rd Compton Lecture Series, 2006 through June 3, 2006, 11:00 a.m. Sean at cosmic variance point to this series of lectures that are being presented each year and in this series the entitled is called, “String Theory: With a View Towards Reality” which will be presented by Nicholas Halmagyi, McCormick Fellow, Enrico Fermi…
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Pierre Auger Observatory
In his excellent paper, Louis LePrince-Ringuet, citing a remark of Powell’s at the Conference of Bagneres-de-Bigorre in 1953, declared that from that date on, particle accelerators took the place of cosmic rays, which more or less faded into the background. And yet, even today accelerators have not caught up with cosmic rays. Pierre Auger on…
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Civilizations Within the Cosmo
In the recent article ‘Conflict between anthropic reasoning and observation’ (gr-qc/0303070) Ken D. Olum, using some inflation-based ideas and the anthropic premise that we should be typical among all intelligent observers in the Universe, arrives at the puzzling conclusion that ‘we should find ourselves in a large civilization (of galactic size) where most observers should…
