The Global Positioning System (GPS), increasingly vital technology for activities including navigating cars and planes, bank financial transfers and more, may be threatened by powerful radio bursts from the sun, a panel of scientists in the US warned today.
"Our increasingly technologically dependent society is becoming increasingly vulnerable to space weather," David L. Johnson, director of the US National Weather Service, said at a briefing.
GPS receivers have become widely used in recent years, using satellite signals to navigate planes, ships and automobiles, and in the use of mobile phones, mining, surveying and many commercial applications.
Science & Technology
Educational software, a $2 billion-a-year industry that has become the darling of school systems across the country, has no significant impact on student performance, according to a study by the U.S. Department of Education.
The long-awaited report amounts to a rebuke of educational technology, a business whose growth has been spurred by schools desperate for ways to meet the testing mandates of President Bush's No Child Left Behind law.
The long-awaited report amounts to a rebuke of educational technology, a business whose growth has been spurred by schools desperate for ways to meet the testing mandates of President Bush's No Child Left Behind law.
A rib bone supposedly found at the site where French heroine Joan of Arc was burned at the stake has been found to belong to an egyptian mummy. It is dated between the 7th and 3rd century BC.
The bone, a piece of cloth and a cat femur were said to have been recovered after the 19-year-old was burned in 1431 in the town of Rouen. In 1909 - the year Joan of Arc was beatified - scientists declared it "highly probable" that the relics were hers.
It is specualted that it was faked to boost her standing as a church figure.
The bone, a piece of cloth and a cat femur were said to have been recovered after the 19-year-old was burned in 1431 in the town of Rouen. In 1909 - the year Joan of Arc was beatified - scientists declared it "highly probable" that the relics were hers.
It is specualted that it was faked to boost her standing as a church figure.
OTTAWA - Fearing the effects of forest fires and tree-destroying insect infestations, the federal government has decided against using Canada's forests in the calculations for totalling up the country's greenhouse-gas emissions.
Instead of forests being used as a credit to offset other emissions, the government is now afraid that including forests in the formula could drive up Canada's climate-change burden.
Instead of forests being used as a credit to offset other emissions, the government is now afraid that including forests in the formula could drive up Canada's climate-change burden.
The numbers are damning. Within 15 years 98% of the rainforests of Indonesia and Malaysia will be gone, little more than a footnote in history. With them will disappear some of the world's most important wildlife species, victims of the rapacious destruction of their habitat in what conservationists see as a lost cause.
How much effort should we expend to ward off the possibility that an asteroid might some day collide with Earth? Experts attending a recent conference in Washington lamented the failure of the federal government - indeed, of the entire world - to take the threat seriously enough. The National Aeronautics and Space Administration, at virtually the same moment, advised Congress on steps that could be taken to find and divert threatening asteroids only to conclude that it couldn't afford them.
That seems shortsighted. The risk is remote, but the consequences are potentially catastrophic. It would seem wise, at a minimum, to look harder for any death-dealing rocks that might menace us.
The encouraging news is that the most horrendous hazards - asteroids like the one that wiped out the dinosaurs or even smaller objects whose impact could disrupt the global environment - have mostly been identified under a $4 million-a-year survey program. The space agency estimates that there are some 1,100 near-Earth objects whose diameters exceed six-tenths of a mile, big enough to destroy a medium-sized state and kick up enough dust to affect global climate and crop production. The survey has already identified more than 700 of them. None are on a path to collide with Earth.
That seems shortsighted. The risk is remote, but the consequences are potentially catastrophic. It would seem wise, at a minimum, to look harder for any death-dealing rocks that might menace us.
The encouraging news is that the most horrendous hazards - asteroids like the one that wiped out the dinosaurs or even smaller objects whose impact could disrupt the global environment - have mostly been identified under a $4 million-a-year survey program. The space agency estimates that there are some 1,100 near-Earth objects whose diameters exceed six-tenths of a mile, big enough to destroy a medium-sized state and kick up enough dust to affect global climate and crop production. The survey has already identified more than 700 of them. None are on a path to collide with Earth.
Imagine the consternation that your high school physics teacher would have shown if, during a lab demonstration, the little wheeled block placed on an inclined plane had violated the law of gravity. Imagine the block sometimes speeding up, sometimes slowing down, and sometimes stopping dead on the slope. Scientists have faced a similar situation as they've studied some of Antarctica's most massive glaciers. The researchers are eager to understand the behavior of these ice streams because they have considerable influence on sea levels worldwide.
Scientists estimate that ice streams contribute about 90 percent of the ice flowing directly off Antarctica into the surrounding sea. However, "we can't now predict how much ice will flow into the sea in the future," says Ted A. Scambos, a glaciologist at the National Snow and Ice Data Center in Boulder, Colo.
Some factors that influence ice streams are well known, but others are just being revealed. New findings show complex aspects of ice streams that have yet to be incorporated into models of how such ice behaves, Scambos notes.
Scientists estimate that ice streams contribute about 90 percent of the ice flowing directly off Antarctica into the surrounding sea. However, "we can't now predict how much ice will flow into the sea in the future," says Ted A. Scambos, a glaciologist at the National Snow and Ice Data Center in Boulder, Colo.
Some factors that influence ice streams are well known, but others are just being revealed. New findings show complex aspects of ice streams that have yet to be incorporated into models of how such ice behaves, Scambos notes.
The story of some violent historic earthquakes may need to be revisited, according to a study published in the April issue of the Bulletin of the Seismological Society of America (BSSA). Seismologists rely on written accounts, mostly local newspaper articles, to judge how strongly the ground shook during earthquakes that predate the use of current instrumentation. Those news accounts have proven to be misleading, say scientists, and reliance upon them must be tempered when evaluating the size of past earthquakes.
By focusing on the most dramatic damage and other effects of an earthquake, news stories can provide an unbalanced view of a disaster. For historical earthquakes it is difficult to estimate the effects of this bias. However, a recently deadly earthquake--the M7.6 Bhuj, India earthquake of 2001--provided an unprecedented opportunity to compare the media accounts with the results of an exhaustive, ground-based survey of damage.
"This study isn't about the media," says Susan E. Hough, co-author of the paper and a seismologist at the U. S. Geological Survey in Pasadena, California. "It isn't the job of the media to provide a detailed survey of the effects of an earthquake. It's the seismologist's job to evaluate media and other written accounts. We need to do careful, balanced assessments of accounts of past earthquakes to understand the hazard from future earthquakes. Media accounts have a built-in bias that is natural to telling any story - whether by a journalist or by an eyewitness."
By focusing on the most dramatic damage and other effects of an earthquake, news stories can provide an unbalanced view of a disaster. For historical earthquakes it is difficult to estimate the effects of this bias. However, a recently deadly earthquake--the M7.6 Bhuj, India earthquake of 2001--provided an unprecedented opportunity to compare the media accounts with the results of an exhaustive, ground-based survey of damage.
"This study isn't about the media," says Susan E. Hough, co-author of the paper and a seismologist at the U. S. Geological Survey in Pasadena, California. "It isn't the job of the media to provide a detailed survey of the effects of an earthquake. It's the seismologist's job to evaluate media and other written accounts. We need to do careful, balanced assessments of accounts of past earthquakes to understand the hazard from future earthquakes. Media accounts have a built-in bias that is natural to telling any story - whether by a journalist or by an eyewitness."
Scientists have discovered caldera of an ancient supervolcano at Kamchatka, RIA Novosti reports.
The ancient remains of an early modern human found in Beijing suggests the "Out of Africa" theory of the dispersal of humans may be more complex than first thought, a study released Monday said.
The fossilized remains date to 38,000 to 42,000 years ago, making it the oldest modern human skeleton from eastern Eurasia, and one of the oldest modern humans from the region, the authors of the paper said.
The specimen is basically a modern human, but with a few archaic characteristics in the teeth and hand bone.
The discovery casts further doubt on the longstanding "Out of Africa" theory which holds that when modern Homo sapiens spread eastwards from sub-Saharan Africa to Eurasia about 65,000 to 25,000 years ago, they simply replaced the native late archaic humans, said anthropologist Erik Trinkaus.
The fossilized remains date to 38,000 to 42,000 years ago, making it the oldest modern human skeleton from eastern Eurasia, and one of the oldest modern humans from the region, the authors of the paper said.
The specimen is basically a modern human, but with a few archaic characteristics in the teeth and hand bone.
The discovery casts further doubt on the longstanding "Out of Africa" theory which holds that when modern Homo sapiens spread eastwards from sub-Saharan Africa to Eurasia about 65,000 to 25,000 years ago, they simply replaced the native late archaic humans, said anthropologist Erik Trinkaus.
