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Spinning water droplets behave like black holes


New Scientist
Mon, 15 Dec 2008 16:26 UTC
Spinning water
© 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.
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Info

'Mind-reading' software could record your dreams

Celeste Biever
New Scientist
Mon, 15 Dec 2008 04:42 UTC
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.
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Telescope

Milky Way's twin brown dwarfs found

Rachel Courtland
New Scientist
Wed, 10 Dec 2008 04:33 UTC
object 2M0939
© 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.
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Clock

Happy New Year? Just wait a second


Daily Mail
Thu, 11 Dec 2008 23:48 UTC
Big Ben
© 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.
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Palette

Japanese Group Reconstructs Visual Images from Brain Activity Patterns

Yousuke Ogasawara
Nikkei Electronics / Tech-On!
Fri, 12 Dec 2008 13:19 UTC
Brain images
© 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.
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Frog

Ancient armored amphibian had world's oddest bite

Will Dunham
Reuters
Sun, 14 Dec 2008 06:30 UTC
A peculiar amphibian that was clad in bony armor prowled warm lakes 210 million years ago, catching fish and other tasty snacks with one of the most unusual bites in the history of life on Earth.

The creature called Gerrothorax pulcherrimus, which lived alongside some of the early dinosaurs, opened its mouth not by dropping its lower jaw, as other vertebrate animals do. Instead, it lifted back the top of its head in a way that looked a lot like lifting the lid of a toilet seat.

"It's weird. It's the ugliest animal in the world," Harvard University's Farish Jenkins, one of the scientists who describe the mechanics of its bite in the Journal of Vertebrate Paleontology, said in a telephone interview on Friday.

"You almost can't imagine holding your jaws still and lifting your head back to take a bite," Jenkins said.

"There are some vertebrates that will lift their heads slightly or the upper jaws (when they bite). Some salamanders do it slightly. Some fish do it slightly. But no animal is known to have done it this extensively," Jenkins added.
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Info

Biggest Full Moon of the Year


Science at NASA
Fri, 12 Dec 2008 18:01 UTC
No, you can not see Neil Armstrong's footprint. But go ahead and look: The full Moon of Dec. 12th is the biggest and brightest full Moon of the year.

It's no illusion. Some full Moons are genuinely larger than others and this Friday's is a whopper. Why? The Moon's orbit is an ellipse with one side 50,000 km closer to Earth than the other: diagram. In the language of astronomy, the two extremes are called "apogee" (far away) and "perigee" (nearby). On Dec. 12th, the Moon becomes full a scant 4 hours after reaching perigee, making it 14% bigger and 30% brighter than lesser full Moons we've seen earlier in 2008.
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Telescope

Geminid Meteor Shower


Space Weather
Fri, 12 Dec 2008 17:59 UTC
The annual Geminid meteor shower peaks on Dec. 13th and Dec. 14th when Earth passes through a stream of debris from extinct comet 3200 Phaethon. Bright moonlight will reduce the number of visible meteors from the usual 100/hr to only 20/hr or so. That's still a nice show.
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Meteor

Constant Comet Threat

Michael Schirber
Astrobiology Magazine
Fri, 12 Dec 2008 16:28 UTC
Halley's Comet
© Lick Observatory
Halley's Comet becomes visible to the unaided eye about every 76 years as it nears the sun.
It certainly captures the imagination: a star passing silently by our solar system knocks a deadly barrage of comets towards Earth. However, recent simulations by one group of researchers has shown that these star-induced comet showers may not be as dramatic as once thought.

The idea of nearby stars influencing comets goes back to 1950, when the astronomer Jan Hendrik Oort hypothesized an invisible repository of comets - the so-called Oort cloud - swarming around the solar system out to a distance of 100,000 AU (one AU is the distance between the sun and the Earth).

Oort assumed that stars passing through the cloud would cause a fresh batch of comets to fall in towards the sun, where they become visible to astronomers. Such a disturbance could have long term effects.

"The comets we see now could be from a stellar passage hundreds of millions of years ago," said Hans Rickman of the Uppsala Astronomical Observatory in Sweden.

However, Rickman and his colleagues have confirmed that star encounters alone cannot explain comet behavior. Using a computer model of the Oort cloud, they show that gravity effects from the galaxy are equally important. The results are reported in a recent article in the journal Celestial Mechanics and Dynamical Astronomy.

Comment: Have you read Cosmic Turkey Shoot?

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Display

Archimedes and the 2000-year-old computer

Jo Marchant
New Scientist
Fri, 12 Dec 2008 16:18 UTC
Antikythera mechanism
© Jo Marchant
The largest recovered fragment of the Antikythera mechanism, in the National Archaeological Museum in Athens.
Marcellus and his men blockaded Syracuse, in Sicily, for two years. The Roman general expected to conquer the Greek city state easily, but the ingenious siege towers and catapults designed by Archimedes helped to keep his troops at bay.

Then, in 212 BC, the Syracusans neglected their defences during a festival to the goddess Artemis, and the Romans finally breached the city walls. Marcellus wanted Archimedes alive, but it wasn't to be. According to ancient historians, Archimedes was killed in the chaos; by one account a soldier ran him through with a sword as he was in the middle of a mathematical proof.

One of Archimedes's creations was saved, though. The general took back to Rome a mechanical bronze sphere that showed the motions of the sun, moon and planets as seen from Earth.

The sphere stayed in Marcellus's family for generations, until the Roman author Cicero saw it in the first century BC. "The invention of Archimedes deserves special admiration because he had thought out a way to represent accurately by a single device for turning the globe those various and divergent movements with their different rates of speed," he wrote. "The moon was always as many revolutions behind the sun on the bronze contrivance as would agree with the number of days it was behind it in the sky."
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