Green black holes, Allen Telescope Array and asteroid impact

Welcome! "Alien Life" tracks the latest discoveries and thoughts in the various elements of the famous Drake Equation. Here's today's news:
g Stars - Black holes are the most fuel efficient engines in the Universe, according to a new study using NASA's Chandra X-ray Observatory. By making the first direct estimate of how efficient or "green" black holes are, this work gives insight into how black holes generate energy and affect their environment. See article.
g Abodes - The atmospheric carbon dioxide concentration is increasing as a consequence of the large-scale use of fossil fuels in the industrial era. This has apparently brought about a stronger relative increase in the light carbon isotope 12C. Due to this the ratio of the stable carbon isotopes 13C/12C has show a clearly measurable decrease of 0.1 percent. However in the Jurassic and Cretaceous periods, 180 million and 120 million years ago, there were periods with a shift four times as large in a period of just several tens of thousands of years. Where did all of that light carbon suddenly come from? See article.
g Life - In findings that may offer insight into how evolution operates, a Duke University evolutionary ecologist reported evidence that aggressive male western bluebirds out-compete less aggressive males for preferred breeding territories. In the process, she found that more-aggressive and milder mannered birds also tended to breed in different settings that favor different body types. See article.
g Intelligence - If you're down in the dumps, you might just think about watching a funny movie. A new study suggests that the mere expectation of laughter makes us feel good. See article.
g Message - SETI and the University of California at Berkeley decided they needed their own instrument, so they started developing the Allen Telescope Array. See article.
g Cosmicus - Over the last few decades there has been a great deal of debate about the level of danger posed by impacts from asteroids and comets. It appears the world needs to take the threat of asteroid strikes a lot more seriously. See article.
g Learning - Here’s a good Web site that gives an general overview of astrobiology for kids: “Astrocentral.” See article.
g Imagining - Like first contact stories? Then be sure to read Robert Heinlein’s novel “Have Spacesuit, Will Travel,” published by Scribners in 1958.
g Aftermath - Decades after Hollywood first made the leap between alien life and the threat of contamination, a scientist has issued a similar warning. U.S. Geological Survey geologist Jeffrey Kargel says convincing evidence uncovered by NASA's robotic rover Opportunity that water once flowed on Mars means scientists should proceed cautiously in bringing back potentially germ-laden samples of the Red Planet. See article.

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