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| ©BBC |
| Black hole: A source of 'cosmic bullets'? |
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Black holes are the most likely source of the mysterious ultra high-energy cosmic rays that bombard the planet, scientists have discovered.
A previously undiscovered type of aurora could be brightening the skies over the poles. That's the conclusion from satellite images of the poles showing the new phenomenon above Antarctic in 2004.
The conventional aurora borealis in the Arctic and aurora australis in the Antarctic are typically seen as curtains of brightly coloured light descending through the atmosphere near the poles. The light is generated when electrons from the solar wind become trapped and accelerated by the Earth's magnetic field to energies in excess of 1 kiloelectronvolt.
The conventional aurora borealis in the Arctic and aurora australis in the Antarctic are typically seen as curtains of brightly coloured light descending through the atmosphere near the poles. The light is generated when electrons from the solar wind become trapped and accelerated by the Earth's magnetic field to energies in excess of 1 kiloelectronvolt.
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| ©GRL/Zhang |
| A series of satellite images shows the wave of high-energy polar rain moving through the centre of a ring of aurora australis on 22 July 2004 |
NASA penny-pinching risks exposing humankind to a planetary catastrophe if a big enough asteroid evades detection and slams into Earth, US lawmakers warned Thursday.
But the US space agency said the chances of a new "Near-Earth Object" (NEO) like the one that wiped out the dinosaurs were too remote to divert scarce resources.
But the US space agency said the chances of a new "Near-Earth Object" (NEO) like the one that wiped out the dinosaurs were too remote to divert scarce resources.
An international team of researchers has taken a key step in figuring out the source of cosmic rays that have puzzled scientists for decades.
Cosmic rays are protons or whole atomic nuclei that have been flung into space to travel at near the speed of light. They come in different varieties, with low- and medium-energy rays produced by exploding stars, or even by our own sun.
Cosmic rays are protons or whole atomic nuclei that have been flung into space to travel at near the speed of light. They come in different varieties, with low- and medium-energy rays produced by exploding stars, or even by our own sun.
African farmers have tried everything to stop errant elephants from trampling over their land and crops: from burning tyres and shining torches, to erecting physical barriers. Now, it seems, bees could be the answer to their prayers.
Experiments carried out by Lucy King of the University of Oxford and colleagues suggest that even the sound of bees is enough to send elephants scampering away instantly.
"They really bolted," says King, who played 4-minute recordings of bees to 17 herds of elephants in Kenya's Buffalo Springs and Samburo National Reserves. "One herd even ran across a river to get away," she adds.
Experiments carried out by Lucy King of the University of Oxford and colleagues suggest that even the sound of bees is enough to send elephants scampering away instantly.
"They really bolted," says King, who played 4-minute recordings of bees to 17 herds of elephants in Kenya's Buffalo Springs and Samburo National Reserves. "One herd even ran across a river to get away," she adds.
Time ain't what it used to be.
A hundred years or so ago, we thought that the seconds ticked away predictably. Tick followed tock, followed tick.
And clocks ran...well, like clockwork. Then along came Einstein and everything changed.
His theories of relativity dealt a blow to our naive ideas about time. Hitch a ride on a rocket travelling close to the speed of light, and time slows to a virtual standstill. The same happens if you park near a black hole and feel its awesome gravity. Even worse, space-time becomes so warped inside a black hole that space and time actually switch places.
Now just as we're getting to grips with time's weirdness, one daring physicist has dropped another bombshell. "There isn't just one dimension of time," says Itzhak Bars of the University of Southern California in Los Angeles. "There are two. One whole dimension has until now gone entirely unnoticed by us."
A hundred years or so ago, we thought that the seconds ticked away predictably. Tick followed tock, followed tick.
And clocks ran...well, like clockwork. Then along came Einstein and everything changed.
His theories of relativity dealt a blow to our naive ideas about time. Hitch a ride on a rocket travelling close to the speed of light, and time slows to a virtual standstill. The same happens if you park near a black hole and feel its awesome gravity. Even worse, space-time becomes so warped inside a black hole that space and time actually switch places.
Now just as we're getting to grips with time's weirdness, one daring physicist has dropped another bombshell. "There isn't just one dimension of time," says Itzhak Bars of the University of Southern California in Los Angeles. "There are two. One whole dimension has until now gone entirely unnoticed by us."
Almost a century after a mysterious explosion in Russia flattened a huge swath of Siberian forest, scientists have found what they believe is a crater made by the cosmic object that made the blast.
The crater was discovered under a lake near the Podkamennaya Tunguska River in western Siberia, where the cataclysm, known as the Tunguska event, took place.
The crater was discovered under a lake near the Podkamennaya Tunguska River in western Siberia, where the cataclysm, known as the Tunguska event, took place.
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| ©www-th.bo.infn.it/tunguska / University of Bologna |
| A three-dimensional rendering of Lake Cheko in Tunguska, Siberia. The level of the lake is lowered 40 meters (131 feet) to emphasize its cone-like shape. |
For half a century, social psychologists have been trying to figure out the human gift for rationalizing irrational behavior. Why did we evolve with brains that salute our shrewdness for buying the neon yellow car with bad gas mileage? The brain keeps sending one message - Yesss! Genius! - while our friends and family are saying, "Well... "
This self-delusion, the result of what's called cognitive dissonance, has been demonstrated over and over by researchers who have come up with increasingly elaborate explanations for it. Psychologists have suggested we hone our skills of rationalization in order to impress others, reaffirm our "moral integrity" and protect our "self-concept" and feeling of "global self-worth."
Comment: Or even shrink back from the what we are taught to believe versus what we actually see happening around us, compounded by the fact that either one of those might not feel right to begin with.
This self-delusion, the result of what's called cognitive dissonance, has been demonstrated over and over by researchers who have come up with increasingly elaborate explanations for it. Psychologists have suggested we hone our skills of rationalization in order to impress others, reaffirm our "moral integrity" and protect our "self-concept" and feeling of "global self-worth."
Comment: Or even shrink back from the what we are taught to believe versus what we actually see happening around us, compounded by the fact that either one of those might not feel right to begin with.
Australian scientists studying humpback whales sounds say they have begun to decode the whale's mysterious communication system, identifying male pick-up lines and motherly warnings.
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| ©REUTERS/Russell Boyce |
| A humpback whale performs a "tail slap" by slapping its tail flukes on the surface of the water in Hervey Bay off the east coast of Australia in this file photo from Aug. 7, 2006. |
Space Shuttle Discovery landed in Cape Canaveral, Florida this evening at 19:01 CET (18:01 UT), completing one of the most complex assembly missions to the International Space Station to date, bringing back seven crew members, including ESA astronaut Paolo Nespoli.
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| ©ESA - S. Corvaja 2007 |
| Space shuttle Discovery |
Comment: Maybe the people in NASA know there are not just a few space rocks flying around, but many, and they see no point in investing any money that would reveal a little of their secret to the masses.