Astronomy

An overview is given of various dark matter candidates. Among the many suggestions given in the literature, axions, inert Higgs doublet, sterile neutrinos, supersymmetric particles and Kaluza-Klein particles are discussed.

The 6dF Galaxy Survey (6dFGS) has mapped the nearby universe over nearly half the sky.

Of the twenty amino acids used in proteins, ten were formed in Miller's atmospheric discharge experiments. The two other major proposed sources of prebiotic amino acid synthesis include formation in hydrothermal vents and delivery to Earth via meteorites. We combine observational and experimental data of amino acid frequencies formed by these diverse mechanisms and show that, regardless of the source, these ten early amino acids can be ranked in order of decreasing abundance in prebiotic contexts. This order can be predicted by thermodynamics. The relative abundances of the early amino acids were most likely reflected in the composition of the first proteins at the time the genetic code originated. The remaining amino acids were incorporated into proteins after pathways for their biochemical synthesis evolved. This is consistent with theories of the evolution of the genetic code by stepwise addition of new amino acids. These are hints that key aspects of early biochemistry may be universal.

"The combined actions of thermodynamics and subsequent natural selection suggest that the genetic code we observe on the Earth today may have significant features in common with life throughout the cosmos."

Phoenix landed at the north arctic region on Mars (68.22°N, 234.25°E) on May 25th, 2008. On Mars, this was just before the summer solstice. Phoenix operated for 5 months, and was able to observe conditions as the seasons changed from summer to winter, giving science teams an unprecedented look at the planet's changing weather patterns, including frost and precipitation.

A team of scientists from the California Institute of Technology, Princeton, Drexel University, and the Massachusetts Institute of Technology have formed the first professional scientific organization based entirely in virtual worlds. Meta Institute for Computational Astrophysics (MICA) conducts professional seminars and popular lectures, among other events, for its growing membership.

An exciting new astrophysics mission led by NASA's Goddard Space Flight Center in Greenbelt, Md., will provide a revolutionary window into the universe. Named the Gravity and Extreme Magnetism Small Explorer (GEMS), the satellite will be the first to systematically measure the polarization of cosmic X-ray sources.

Why and how did the Thirty Meter Telescope project decide to build at Mauna Kea?

Gamma-ray bursts (GRB) are the most powerful explosions known in the Universe; most originate in distant galaxies. A large percentage of bursts likely arise from the explosion of stars over 15 times more massive than our Sun. Experts believe that...