San Francisco, California - The most energetic particles in the electromagnetic spectrum could pose a danger to commercial airline passengers.
About every 3000 hours of flying time, a plane is hit with a bolt of lightning. Recently, spacecraft have found gamma rays can be created by thunder storms, and according to new research presented at the American Geophysical Union annual meeting this week, the rays could be intense enough to cause radiation sickness.
Science & Technology
© NASA/JPL
The Cassini Radar Mapper imaged Titan on Feb. 22, 2008 (as shown on the left) and April 30, 2006 (as shown on the right).
The Cassini Radar Mapper imaged Titan on Feb. 22, 2008 (as shown on the left) and April 30, 2006 (as shown on the right).
"Cryovolcanoes are some of the most intriguing features in the solar system," said Rosaly Lopes, a Cassini radar team investigation scientist from NASA's Jet Propulsion Laboratory in Pasadena, Calif. "To put them in perspective -- if Mount Vesuvius had been a cryovolcano, its lava would have frozen the residents of Pompeii."
Rather than erupting molten rock, it is theorized that the cryovolcanoes of Titan would erupt volatiles such as water, ammonia and methane. Scientists have suspected cryovolcanoes might inhabit Titan, and the Cassini mission has collected data on several previous passes of the moon that suggest their existence. Imagery of the moon has included a suspect haze hovering over flow-like surface formations. Scientists point to these as signs of cryovolcanism there.
Quantum entanglement, which Einstein dubbed "spooky action at a distance", would be the perfect way to communicate - if technical hurdles could be overcome.
The method involves linking the quantum properties of two objects such that a change to one is instantly reflected in the other - offering the prospect of instant communication from opposite sides of the globe.
But the longest distance over which communication has been achieved is still less than 200 kilometres. The inability of the gas-based quantum computer memory used to hold onto information for more than a fraction of a second is to blame.
Now a way to have that memory store quantum information for longer opens up the possibility of entangled communication over 1000 kilometres.
The method involves linking the quantum properties of two objects such that a change to one is instantly reflected in the other - offering the prospect of instant communication from opposite sides of the globe.
But the longest distance over which communication has been achieved is still less than 200 kilometres. The inability of the gas-based quantum computer memory used to hold onto information for more than a fraction of a second is to blame.
Now a way to have that memory store quantum information for longer opens up the possibility of entangled communication over 1000 kilometres.
© ANU
The first digital survey of the southern sky, which includes the Milky Way's centre, is set to begin as early as April 2009.
The first digital survey of the southern sky, which includes the Milky Way's centre, is set to begin as early as April 2009.
The northern sky has been mapped in unprecedented detail by the Sloan Digital Sky Survey, whose telescope is based in Sunspot, New Mexico.
In its first eight years, Sloan plotted the positions of about a million galaxies over more than a quarter of the northern sky. It is now observing more distant galaxies in an effort to study dark energy's effect on the universe over time.
Now, a project called SkyMapper will survey the southern sky, including the Milky Way's crowded centre, from its perch on Siding Spring Mountain in southeastern Australia.
Over five years, astronomers plan to use SkyMapper's 1.35-metre telescope and 268-Megapixel camera to map the sky six times, each time in six different colours. The survey may begin as early as April 2009.
© n/a
"When we tried to remove the soil wrapped around the coffin, a piece of rock suddenly dropped off and hit the ground with a metallic sound,? said Jiang Yanyu, former curator of the Guangxi Autonomous Region Museum.
"We picked up the object, and found it was a ring. After removing the covering soil and examining it further, we were shocked to see it was a watch."
The result of a Danish ice drilling project has become the international standard for the termination of the last glacial period. It ended precisely 11,711 years ago.
A Danish ice drilling project has conclusively ended the discussion on the exact date of the end of the last ice age.
The extensive scientific study shows that it was precisely 11,711 years ago - and not the indeterminate figure of 'some' 11,000 years ago - that the ice withdrew, allowing humans and animals free reign.
According to the Niels Bohr Institute (NBI) in Copenhagen, the very precise dating of the end of the last Ice Age has made Denmark the owner of the "Greenwich Mean Time" of the end of the last glacial period and beginning of the present climate - the so-called International Standard Reference.
A Danish ice drilling project has conclusively ended the discussion on the exact date of the end of the last ice age.
The extensive scientific study shows that it was precisely 11,711 years ago - and not the indeterminate figure of 'some' 11,000 years ago - that the ice withdrew, allowing humans and animals free reign.
According to the Niels Bohr Institute (NBI) in Copenhagen, the very precise dating of the end of the last Ice Age has made Denmark the owner of the "Greenwich Mean Time" of the end of the last glacial period and beginning of the present climate - the so-called International Standard Reference.
© University of Manchester
A 4,000-year-old amber necklace has been unearthed in England.
A 4,000-year-old amber necklace has been unearthed in England.
It is the first time a necklace of this kind from the early Bronze Age has been found in north west England.
Peter Noble from The University of Manchester said: "An amber necklace of this sort was one of the most important ways that people of the early Bronze Age could display their power and influence.
"The fact that it has been found in the north west of England is pretty amazing and extremely rare."
Dozens of different sized pierced amber beads are linked together on a length of fibre to form the beautiful artifact.
© NOAA's Space Weather Prediction Center
The X9-class solar flare of Dec. 5, 2006, observed by the Solar X-Ray Imager aboard NOAA's GOES-13 satellite.
The X9-class solar flare of Dec. 5, 2006, observed by the Solar X-Ray Imager aboard NOAA's GOES-13 satellite.
"We've detected a stream of perfectly intact hydrogen atoms shooting out of an X-class solar flare," says Richard Mewaldt of the California Institute of Technology. "What a surprise! If we can understand how these atoms were produced, we'll be that much closer to understanding solar flares."
The event occurred on Dec. 5, 2006. A large sunspot rounded the sun's eastern limb and with little warning it exploded. On the "Richter scale" of flares, which ranks X1 as a big event, the blast registered X9, making it one of the strongest flares of the past 30 years.
NASA managers braced themselves. Such a ferocious blast usually produces a blizzard of high-energy particles dangerous to both satellites and astronauts. An hour later they arrived, but they were not the particles researchers expected.
© NASA and H. Richer (University of British Columbia)
White dwarfs in the globular cluster M4. In this picture, only the faintest stars are white dwarfs.
White dwarfs in the globular cluster M4. In this picture, only the faintest stars are white dwarfs.
It is so hot that its photosphere exhibits emission lines in the ultraviolet spectrum, a phenomenon that has never been seen before. These emission features stem from extremely ionized calcium (nine-fold ionized, i.e., CaX), which is the highest ionization stage of a chemical element ever discovered in a photospheric stellar spectrum.
Stars of intermediate mass (1-8 solar masses) terminate their life as an Earth-sized white dwarf after the exhaustion of their nuclear fuel. During the transition from a nuclear-burning star to the white dwarf stage, the star becomes very hot. Many such objects with surface temperatures around 100 000 Kelvin are known. Theories of stellar evolution predict that the stars can be much hotter. However, the probability of catching them in such an extremely hot state is low, because this phase is rather short-lived.
© NASA
If the moon Europa is tilted on its axis even slightly as it orbits the giant planet Jupiter, then Jupiter's gravitational pull could be creating powerful waves in Europa's ocean.
If the moon Europa is tilted on its axis even slightly as it orbits the giant planet Jupiter, then Jupiter's gravitational pull could be creating powerful waves in Europa's ocean.
If the moon Europa is tilted on its axis even slightly as it orbits the giant planet Jupiter, then Jupiter's gravitational pull could be creating powerful waves in Europa's ocean, according to Robert Tyler, an oceanographer with the University of Washington's Applied Physics Laboratory and author of a letter in the Dec. 11 Nature. As those waves dissipate, they would give off significant heat energy.
Depending on the amount of tilt, the heat generated by the ocean flow could be 100 to thousands of times greater than the heat generated by the flexing of Europa's rocky core in response to gravitational pull from Jupiter and the other moons circling that planet.
That's the current assumption - that oceans on moons are heated mainly by this flexing of their cores. In the case of Europa, it also has been thought that the thick ice covering its ocean probably generates some heat as two sides of cracked ice rub together in response to gravitational pull.
"If my work is correct then the heat source for Europa's ocean is the ocean itself rather than what's above or below it," Tyler says. "And we must form a new vision of the ocean habitat that involves strong ocean flow rather than the previously assumed sluggish flows."
