Saturday, 22 December 2012
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Wednesday, 7 November 2012
The Great Attractor is a gravity anomaly in intergalactic space within the range of the Centaurus Supercluster that reveals the existence of a localized concentration of mass equivalent to tens of thousands of Milky Ways, observable by its effect on the motion of galaxies and their associated clusters over a region hundreds of millions of light years across.
These galaxies are all redshifted, in accordance with the Hubble Flow, indicating that they are receding relative to us and to each other, but the variations in their redshift are sufficient to reveal the existence of the anomaly. The variations in their redshifts are known as peculiar velocities, and cover a range from about +700 km/s to −700 km/s, depending on the angular deviation from the direction to the Great Attractor.
Quantum information has leapt through the air about 100 kilometers or more in two new experiments, farther and with greater fidelity than ever before. The research brings truly long-distance quantum communication networks, in which satellites could beam encrypted information around the globe, closer to reality.
Tuesday, 6 November 2012
An invisible web thought to span the cosmos has now revealed one of its strands.
That thread is spun of dark matter and connects two titanic clusters of galaxies, some of the most massive objects in the universe. Its discovery supports the idea that galaxy clusters grow at the intersections of such filaments, and its heft backs the claim that filaments hide more than half of all matter.