‘Heartbeats’ may keep galaxies churning
Until now, astronomers haven’t been able to offer a full explanation for why the Milky Way and other galaxies produce new stars at a relative snail’s pace. While they have known for decades that high turbulence keeps huge clouds of hydrogen gas from condensing into stars, they haven’t identified all the causes of the galactic perturbations. In a coming report researchers in San Diego say they have discovered that a well-known, but overlooked source of heating?regular outbursts of ultraviolet radiation from clusters of very large, bright stars?may play a significant role in keeping the Milky Way’s gas continually stirred up.
In the spring of 2001, two robotic Carbon Explorer floats recorded the rapid growth of phytoplankton in the upper layers of the North Pacific Ocean after a passing storm had deposited iron-rich dust from the Gobi Desert. The carbon measurements, reported in the October 25 issue of Science, are the first direct observation of wind-blown terrestrial dust fertilizing the growth of aquatic plant life.
Contrary to an opinion held by some researchers, a new analysis of more than 20 years of historical data has found no evidence that the increasing number of large icebergs off Antarctica’s coasts is a result of global warming trends. “The dramatic increase in the number of large icebergs as recorded by the National Ice Center database does not represent a climatic change,” said Brigham Young University’s David Long. “Our reanalysis suggests that the number of icebergs remained roughly constant from 1978 to the late 1990s.” Using BYU’s supercomputers, Long enhanced images of the waters around Antarctica transmitted by satellite. Comparing this data to records from the federal government’s National Ice Center, which tracks icebergs larger than ten miles on one side, he determined that previous tracking measures were inadequate, resulting in a gross undercounting.
An extrasolar planet has been discovered using a new technique that will allow astronomers to detect planets no other current method can. Planets around other stars have been previously detected only by the effect they have on their parent star, limiting the observations to large, Jupiter-like planets and those in very tight orbits. The new method uses the patterns created in the dust surrounding a star to discern the presence of a planet that could be as small as Earth or in an orbit so wide that it would take hundreds of years to observe its effect on its star.
In case there was any doubt, researchers in — where else? — Los Angeles have determined that living near a freeway exposes you to a lot more pollution than if you lived further away. Specifically, a UCLA team found people who live, work or travel within 165 feet downwind of a major freeway or busy intersection are exposed to potentially hazardous particle concentrations up to 30 times greater than normal background levels.
For the latter part of the 20th century, much of what we knew about plasma fusion came out of