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Galaxy study validates general relativity on cosmic scale, existence of dark matter By News Releases (University of California - Berkeley) While general relativity describes well the behavior of the solar system, Einstein's theory of gravity and spacetime has not been tested on cosmological scales. Now, a team that includes UC Berkeley physicist Uros Seljak has analyzed data on 70,000 galaxies to show that the theory is so far the best description of the universe, at least out to 3.5 billion light years from Earth. Specifically, theories without dark matter do not fit the observations.

Mysterious cosmic 'dark flow' tracked deeper into universe By News Releases (NASA/Goddard Space Flight Center) Distant galaxy clusters mysteriously stream at a million miles per hour along a path roughly centered on the southern constellations Centaurus and Hydra. A new study led by Alexander Kashlinsky at NASA's Goddard Space Flight Center in Greenbelt, Md., tracks this collective motion -- dubbed the "dark flow" -- to twice the distance originally reported.

Scientists discover 'catastrophic event' behind the halt of star birth in early galaxy formation By News Releases (Durham University) Scientists have found evidence of a catastrophic event they believe was responsible for halting the birth of stars in a galaxy in the early universe.

Bully galaxy rules the neighborhood By News Releases (ESA/Hubble Information Centre) In general, galaxies can be thought of as "social" -- hanging out in groups and frequently interacting. However, this recent NASA/ESA Hubble Space Telescope image highlights how some galaxies appear to be hungry loners. These cosmic oddities have set astronomers on the "case of the missing neighbor galaxies."

University of Arizona receives contracts worth $6 million to support quest for dark energy By News Releases (University of Arizona) University of Arizona research and development groups were selected to develop and manufacture key technology for the first major undertaking to investigate the mystery of dark energy in the universe.

First of missing primitive stars discovered By News Releases (Harvard-Smithsonian Center for Astrophysics) Astronomers have discovered a relic from the early universe -- a star that may have been among the second generation of stars to form after the Big Bang. Located in the dwarf galaxy Sculptor some 290,000 light-years away, the star has a remarkably similar chemical make-up to the Milky Way's oldest stars. Its presence supports the theory that our galaxy underwent a "cannibal" phase, growing to its current size by swallowing dwarf galaxies and other galactic building blocks.

NASA's Fermi probes 'dragons' of the gamma-ray sky By News Releases (NASA/Goddard Space Flight Center) One of the pleasures of perusing ancient maps is locating regions so poorly explored that mapmakers warned of dragons and sea monsters. Now, astronomers using NASA's Fermi Gamma-ray Space Telescope find themselves in the same situation as cartographers of old. A new study of the ever-present fog of gamma rays from sources outside our galaxy shows that less than a third of the emission arises from what astronomers once considered the most likely suspects -- black-hole-powered jets from active galaxies.

Astronomically large lenses measure the age and size of the universe By News Releases (DOE/SLAC National Accelerator Laboratory) Using entire galaxies as lenses to look at other galaxies, researchers have a newly precise way to measure the size and age of the universe and how rapidly it is expanding. The measurement determines a value for the Hubble constant, which indicates the size of the universe, and confirms the age of the universe as 13.75 billion years old, within 170 million years. The results also confirm the strength of dark energy, responsible for accelerating the expansion of the universe.