On the horizon
News from the frontiers of science.
Atmospheric methane – a far more potent greenhouse gas than carbon dioxide – has held steady for the past seven years, following 20 years of increases. Scientists making the measurements say the change may result from fewer leaks in pipelines and oil and gas storage facilities. They add that emissions from coal mining and natural-gas production may have been reduced.
The team gathered sea-level air samples from land- and island-based canisters along a rough line from northern Alaska to New Zealand. It's unclear how long the trend might hold. But "we will gain some ground on global warming if methane is not as large a contributor in the future as it has been in the past century," notes F. Sherwood Rowland, a Nobel Prize-winning atmospheric scientist at the University of California at Irvine. He led the team that reported its results in the Nov. 23 issue of Geophysical Research Letters.
In 2000, NASA scientist James Hansen and a colleague argued in a paper in the Proceeding of the National Academies of Science that an immediate focus on curbing less-abundant, but more-potent, greenhouse gases, including methane, could buy time to work out more-effective strategies to reduce carbon-dioxide emissions.
The ancient Greeks knew how to gear up to calculate astronomical events.
A new analysis of fragments from a 2,000-year-old calculator called the Antikythera Mechanism shows that it not only could track the motions of the planets, but it could also duplicate the movements of the moon, based on a complex theory of the moon's motions attributed to mathematician and astronomer Hipparchos (ca. 190-125 BCE).