On the left, an optical image from the Digitized Sky Survey shows Cygnus X-1, outlined in a red box.  Cygnus X-1 is located near large active regions of star formation in the Milky Way, as seen in this image that spans some 700 light years across. An artist's illustration on the right depicts what astronomers think is happening within the Cygnus X-1 system.  Cygnus X-1 is a so-called stellar-mass black hole, a class of black holes that comes from the collapse of a massive star.  New studies with data from Chandra and several other telescopes have determined the black hole's spin, mass, and distance with unprecedented accuracy.

Black holes and other star remnants

Imagine a dog owner with a reflective vest and a black dog without one. In the dark we can see how the dog owner moves, but not the dog. That’s how black holes work, too.

People’s drinking habits around Europe have been charted in the recently completed European Social Survey. Alcohol consumption in European countries varies widely. Men consumed almost twice as many units of alcohol as women, and women in Israel and Central and Eastern Europe drink the least. Illustration: Thinkstock

Who in Europe drinks the most?

For the first time, researchers have found a way to compare how much alcohol Europeans drink. And Britain, Ireland and Portugal top off the list.

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Water reservoirs save lives and create value

While there is considerable opposition to dams and reservoirs in the Western world, reservoirs built to store water during the rainy season so it can be used during the dry season can save lives and secure values when the rains fail.

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