| iSniff: Pocket-Size Pollution Sensors Promise Big Improvement in Monitoring Personal Environment Once large enough to be mistaken for terrorist bombs, portable air pollution monitors are now being shrunk into smaller and smaller wearable devices that can be easily dispatched for environmental detective work: Is black carbon soot emitted by school buses contributing not just to warming global temperatures , but raising childhood asthma rates, too? These new pocket-size sensors could provide more practical and powerful detection of such potential public health risks. [More] rss.sciam.com |
Can Flywheels Help Balance Electricity Supply and Demand? Beacon Power Corp. broke ground today on a 20-megawatt, energy-storage facility in southeastern New York. [More] rss.sciam.com |
Is Ethanol from Corn Bad for the Climate? The Obama administration last week gave the green light to corn ethanol as a low-carbon renewable fuel – in apparent contradiction to California's declaration last summer that the biofuel's carbon footprint was too big to help the state mitigate greenhouse gas emissions. [More] rss.sciam.com |
Doctors Underestimate Environment as Cause for Cancer The President's Cancer Panel on Thursday reported that "the true burden of environmentally induced cancers has been grossly underestimated" and strongly urged action to reduce people's widespread exposure to carcinogens . [More] Carcinogen - Cancer - United States - Health - Government rss.sciam.com |
The Biggest Bang Theory: Astronomers Confirm a New Type of Supernova When our sun comes to its ending in five billion years or so, it will fade into a quiescent white dwarf. Bigger stars go out with a bang--those with more than 10 times the mass of our sun collapse with enough vigor to spark a supernova, one of the most energetic events in the universe. For decades astronomers have suspected the existence of a type of stellar explosion that is bigger still--a “pair-instability” supernova, with 100 times more energy than an ordinary supernova. In the past year two teams of astronomers have finally found it, redrawing in a stroke the limit of how big things can be in this universe of ours.All stars balance gravity with pressure. As light elements such as hydrogen fuse in a star’s core, the reactions generate photons that press outward, counteracting the pull of gravity. In larger stars, pressure at the core is high enough to fuse heavier elements such as oxygen and carbon, creating more photons. But in stars bigger than 100 solar masses or so, there’s a hitch. When oxygen ions begin to fuse with one another, the reaction releases photons that are so energetic, they spontaneously trans­mute into electron-positron pairs. With no photons, there’s no outward pressure--and the star begins to collapse. [More] Star - Supernova - White dwarf - Energy - Sun rss.sciam.com |