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Danish Arctic research dates Ice Age

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.

Info

4,000-year-old Amber Necklace Has Been Unearthed In England

© 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. The rare find was unearthed from a stone-lined grave - known as a Cist - excavated by the team from The University of Manchester Field Archaeology Centre and Mellor Archaeological Trust.

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.

Sun

Solar Flare Surprise: Stream Of Perfectly Intact Hydrogen Atoms Detected

© 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.
Solar flares are the most powerful explosions in the solar system. Packing a punch equal to a hundred million hydrogen bombs, they obliterate everything in their immediate vicinity. Not a single atom should remain intact.

"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.

Sun

Hottest White Dwarf In Its Class

© 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.
Astronomy & Astrophysics is publishing spectroscopic observations with NASA's space-based Far-Ultraviolet Spectroscopic Explorer (FUSE) of the white dwarf KPD 0005+5106. The team of German and American astronomers who present these observations show that this white dwarf is among the hottest stars known so far, with a temperature of 200 000 K at its surface.

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.

Telescope

Jupiter's Moon Europa Does The Wave To Generate Heat

© 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.
One of the moons in our solar system that scientists think has the potential to harbor life may have a far more dynamic ocean than previously thought.

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."

Info

Spinning water droplets behave like black holes

© Richard Hill and Laurence Eaves, University of Nottingham
Spinning water could be used to mimic black hole behaviour.
What does a drop of water have in common with a black hole and an atom? Well, levitating water droplets can now simulate the dynamics of both cosmological and subatomic objects.

Richard Hill and Laurence Eaves at the University of Nottingham, UK, turned to water droplets because the surface tension that holds the drops together can be used to model other forces. For example, the event horizon of a black hole is sometimes thought of as a "stretched" membrane with a surface tension. Similar forces also prevent atoms from flying apart.

The team levitated the droplets using an effect called diamagnetism: when an external magnetic field was applied to the droplets, they created their own opposing magnetic field, initiating a repulsive force strong enough to counteract gravity. To set the droplets spinning, they implanted two tiny electrodes, which generated an electric field.

Info

'Mind-reading' software could record your dreams

Pictures you are observing can now be recreated with software that uses nothing but scans of your brain. It is the first "mind reading" technology to create such images from scratch, rather than picking them out from a pool of possible images.

Earlier this year Jack Gallant and colleagues at the University of California, Berkeley, showed that they could tell which of a set of images someone was looking at from a brain scan.

To do this, they created software that compared the subject's brain activity while looking at an image with that captured while they were looking at "training" photographs. The program then picked the most likely match from a set of previously unseen pictures.

Telescope

Milky Way's twin brown dwarfs found

© NASA/JPL-Caltech
Light from the object 2M0939 seems to come from twin brown dwarfs, making them the dimmest star-like objects yet seen.
Astronomers have found what appear to be the galaxy's dimmest bulbs - two brown dwarfs that are each half as bright as the previous record holder.

Sometimes called 'failed stars', brown dwarfs are compact balls of gas that can perform nuclear fusion, but are not massive enough to sustain the process over their lifetimes.

Now, astronomers led by physicist Adam Burgasser of MIT say they may have found the dimmest yet seen.

The Two Micron All Sky Survey, which mapped the sky at near-infrared wavelengths, originally identified an object known as 2MASS J09393548-2448279 (2M0939), which sits some 17 light years away, as a single brown dwarf.

Clock

Happy New Year? Just wait a second

© PA
With the economic slowdown, 2008 may feel as if it will never end. Now the world's timekeepers are making it even longer by adding a leap second to the last day of the year.

Along with the economy, the Earth itself is slowing down due to the tug of the Sun and Moon, requiring timekeepers to alter their atomic clocks to keep in sync.

So an extra second will be tacked on to December 31 just before midnight, making 2008 - already long with the extra day in February - the longest year since 1992, which also had both a leap day and leap second.

Palette

Japanese Group Reconstructs Visual Images from Brain Activity Patterns

© ATR
The drawing illustrates the "visual image reconstruction" technology developed by the Advanced Telecommunications Research Institute International (ATR) and others, which reconstructs figures seen by a subject into images by measuring human brain activity.
A Japanese research group developed the "visual image reconstruction" technology to reconstruct figures seen by a subject into images by measuring human brain activity.

The group was led by the Advanced Telecommunications Research Institute International (ATR) and National Institute of Information and Communications Technology (NICT).

By using a functional magnetic resonance imaging (fMRI) system, the new technology measures the patterns of brain activity in the cerebral visual cortex invoked by image information entered through eyes. The field of vision is divided into small areas, and the contrast in each area is estimated based on the corresponding brain activity pattern.