Notebook
Monday, September 25, 2006
Mars's Mystery 'Face' Decoded
The best images ever taken of the much-discussed "face on Mars" have conclusively established that it is an unusual formation of mountains, valleys and landslides.
Cameras on the European Space Agency's Mars Express satellite cut through the atmospheric dust and haze in July to provide clear images of the "face" in the planet's Cydonia region. Project scientist Agustin Chicarro said the photos "not only provide a completely fresh and detailed view of an area famous to fans of space myths worldwide but also provide an impressive close-up of an area of great interest for planetary geologists."
The "face on Mars" became a sensation in 1976, when the Viking 1 probe sent back distant images of a Martian landscape that appeared to include a gigantic human face. A NASA news release at the time said the formation "resembles a human head," setting off speculation that it was created by intelligent beings.
NASA scientists had already concluded the "face" was actually an optical illusion caused by the unusual play of light and the formation's surface, but public speculation continued even after a later Mars probe sent back more detailed pictures in 1998 and 2001.
Based on the new photos, scientists said the "face" has many landslides of rock debris and a developing "debris apron." But even as it debunked the notion of a formation created by intelligent beings, the ESA noted that a "naturally skull-shaped structure" was also seen in the Cydonia region.
-- Marc Kaufman
Popular Soup Imperils SharksThe number of sharks being killed to supply the burgeoning demand for shark fin soup is three to four times as high as previous estimates, scientists report in the October issue of Ecology Letters.
The study, a statistical analysis based on records of Hong Kong shark fin traders, calculated that 26 million to 73 million sharks are killed each year.
"The shark fin trade is notoriously secretive, but we were able to tap into fin auction records and convert from fin sizes and weights to whole shark equivalents to get a good handle on the actual numbers," said lead author Shelley Clarke, an American fisheries scientist based in Hong Kong and Japan.
Shark fin soup, which can cost as much as $100 for a bowl serving four people, has long been prized in China. In recent years, demand has grown.
The World Conservation Union estimated earlier this year that 20 percent of shark species are in danger of becoming extinct; Clarke said the new figures show the harvest of blue sharks "is near the maximum sustainable level."
-- Juliet Eilperin
Social Flies Shed Light on SleepEver feel the need to get a couple of extra hours of sleep after a large family gathering? A contentious faculty meeting? A long evening in a singles bar?
Fruit flies know how you feel.
A study last week in the journal Science found that Drosophila fruit flies needed more sleep after spending time around a lot of other flies or learning something that produced a long-term memory.
Indrani Ganguly-Fitzgerald of the Neurosciences Institute in San Diego and Jeff Donlea and Paul J. Shaw of Washington University in St. Louis kept fruit flies either alone or in groups of about 30 immediately after hatching. On Day 5, they watched the flies sleep.
The ones raised in isolation slept about 13 hours a day, while those from the "socially enriched" environment slept about 16 hours.
The reason for sleep isn't fully known, but there is some evidence it helps consolidate learning and memory in the brain. Other experiments these researchers did supported that theory.
They trained male fruit flies to perform a task as part of their courtship ritual. If the flies were deprived of sleep for four hours after the training, they forgot it. If they were allowed to sleep unperturbed for 24 hours and then deprived of sleep, however, they still remembered it.
-- David Brown
Social Flies Shed Light on SleepEver feel the need to get a couple of extra hours of sleep after a large family gathering? A contentious faculty meeting? A long evening in a singles bar?
Fruit flies know how you feel.
A study last week in the journal Science found that Drosophila fruit flies needed more sleep after spending time around a lot of other flies or learning something that produced a long-term memory.
Indrani Ganguly-Fitzgerald of the Neurosciences Institute in San Diego and Jeff Donlea and Paul J. Shaw of Washington University in St. Louis kept fruit flies either alone or in groups of about 30 immediately after hatching. On Day 5, they watched the flies sleep.
The ones raised in isolation slept about 13 hours a day, while those from the "socially enriched" environment slept about 16 hours.
The reason for sleep isn't fully known, but there is some evidence it helps consolidate learning and memory in the brain. Other experiments these researchers did supported that theory.
They trained male fruit flies to perform a task as part of their courtship ritual. If the flies were deprived of sleep for four hours after the training, they forgot it. If they were allowed to sleep unperturbed for 24 hours and then deprived of sleep, however, they still remembered it.
-- David Brown
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