Science & TechnologyS


Telescope

Where Did Venus's Water Go?


Science Daily
Thu, 18 Dec 2008 16:16 UTC
Interaction between Venus and the solar wind
© ESA / C. CarreauInteraction between Venus and the solar wind.
Venus Express has made the first detection of an atmospheric loss process on Venus's day-side. Last year, the spacecraft revealed that most of the lost atmosphere escapes from the night-side. Together, these discoveries bring planetary scientists closer to understanding what happened to the water on Venus, which is suspected to have once been as abundant as on Earth.

The spacecraft's magnetometer instrument (MAG) detected the unmistakable signature of hydrogen gas being stripped from the day-side. "This is a process that was believed to be happening at Venus but this is the first time we measured it," says Magda Delva, Austrian Academy of Sciences, Graz, who leads the investigation.

Thanks to its carefully chosen orbit, Venus Express is strategically positioned to investigate this process; the spacecraft travels in a highly elliptical path sweeping over the poles of the planet.

Water is a key molecule on Earth because it makes life possible. With Earth and Venus approximately the same size, and having formed at the same time, astronomers believe that both planets likely began with similar amounts of the precious liquid. Today, however, the proportions on each planet are extremely different. Earth's atmosphere and oceans contain 100 000 times the total amount of water on Venus. In spite of the low concentration of water on Venus Delva and colleagues found that some 2x1024 hydrogen nuclei, a constituent atom of the water molecule, were being lost every second from Venus's day-side.
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Satellite

Flaw may have sent Beagle 2 to a fiery doom

Paul Marks
New Scientist
Thu, 18 Dec 2008 15:54 UTC
The mystery over what happened to the Beagle 2 spacecraft may have been solved, five years after contact with it was lost as it entered the Martian atmosphere on Christmas Day 2003. An Australian team of hypersonics engineers say a flawed calculation probably resulted in Beagle 2 tumbling out of control as it descended.

Until now, the loss of the probe has been attributed to the general failings of a poorly funded mission: despite an exhaustive enquiry by the European Space Agency, no single cause for the loss of the £50 million spacecraft has been identified.

Beagle 2
© ESAWhy did Beagle 2 disappear?
Beagle 2 was designed to self-stabilise during its descent through the Martian atmosphere. This was to be achieved through careful design of the spacecraft's aerodynamics and centre of gravity, and by spinning the craft as it was released from the European Space Agency's Mars Express orbiter. This generated a gyroscopic force for correcting wobbles as it descended.

The ideal spin rate was difficult to determine because the forces on a spacecraft change sharply as it plunges from the thin upper atmosphere to the denser gas closer to the surface. The Beagle 2 team simulated the forces in both these regimes but could not afford to simulate the way the forces change during the transition between the two. Instead, they estimated the forces using a mathematical process called a bridging function, and settled on a rate of 14 revolutions per minute.
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Info

'Evil water' linked to mysterious drownings


New Scientist
Thu, 18 Dec 2008 15:50 UTC
It may sound like a superstitious excuse for a poor day's swimming, but it is not uncommon for triathletes to complain that the water is behaving badly - even that it is "evil". Now a study suggests what they are feeling is real.

Leo Maas, a fluid dynamicist at the Royal Netherlands Institute for Sea Research, and colleagues found that "dead water" - an obstructive effect encountered by ships at sea - can strike swimmers too.

As ships sail over a layer of warm water sitting over saltier, or colder, layers, waves form in the boundary between the two layers. As these waves grow, they form a gulf beneath the ship, sucking away its speed. This effect can stall boats at sea, reducing their speed by up to 80%.

Maas and his colleagues ran two experiments see if dead water could strike swimmers too.
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Target

Scientists seek ways to ward off killer asteroids

Robert S. Boyd
McClatchy Newspapers
Thu, 18 Dec 2008 15:46 UTC
A blue-ribbon panel of scientists is trying to determine the best way to detect and ward off any wandering space rocks that might be on a collision course with Earth.
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Clock

Calls to scrap the 'leap second' grow

Devin Powell
New Scientist
Thu, 18 Dec 2008 15:43 UTC
clock
© Joe Cornish/GETTY10, 9, 8, 7, 6, 5, 4, 3, 2, 1, and 1 again, happy new year!
At midnight on New Year's Eve, time will stop momentarily. Guardians of atomic clocks around the world will add an extra "leap second" to 2008 to keep time synched with the Earth's rotation. Arguably, the rise of GPS makes this tweak unnecessary.

In 1972, global commerce began to set its clocks by Coordinated Universal Time (UTC), based on the oscillations of the caesium atom. The snag was that other things, such as shipping and aircraft navigation, still relied on UT1 time, which divides one rotation of the Earth into 86,400 seconds. But the Earth's spin is slowing, so the two systems gradually go out of synch. "Over the course of a millennium, the differences would accumulate to about an hour," says Robert Nelson of the Satellite Engineering Research Corporation in Bethesda, Maryland.

To compensate, the ITU, or International Telecommunications Union, adds a leap second to atomic time every few years. However, many argue that we should stop tinkering with time, not least because of the glitches it causes (see "Add second...").

Now a group within the ITU, called Working Party 7A - after deliberating over the leap second for years - has told New Scientist that it recommends abolishing the leap second. Group member Elisa Felicitas Arias, of the International Bureau of Weights and Measures in Paris, France, argues that a timescale that doesn't need regular tweaking is essential in an increasingly interconnected world. What's more, she says, ships and aircraft now navigate via GPS rather than the old time system. GPS runs on a version of atomic time.
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Info

First cases of touch-emotion synaesthesia discovered

Ewen Callaway
New Scientist
Thu, 18 Dec 2008 15:40 UTC
For a 22-year-old woman known as AW, denim evokes feelings of depression, disgust and worthlessness. Corduroy causes confusion, and silk provides utter contentment. She is one of two people known to experience a newly discovered form of synaesthesia, where textures give rise to strong emotions.

HS, another young woman who experiences tactile-emotion synaesthesia, gets no kick out of denim. Fleece and dry leaves disgust her, while the touch of tennis balls, fresh leaves and sand are heaven.

Other forms of synaesthesia include numbers and letters that evoke colours, shapes that evoke tastes shapes and colours with their very own fragrances.

AW and HS's sensations, unusual though they may seem, are an extreme form of the positive feelings most people associate with a soft blanket or the aversion to sharp knives and jagged rocks, says V. S. Ramachandran, a neuroscientist at the University of California, San Diego.

"We have an affinity for fur because when were evolving in the ice age, we needed coats," he says. "This is the architecture on which [tactile-emotion synaesthesia] is built."
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Powertool

Ancient Roman oil lamp "factory town" found in Italy

Rossella Lorenzi
Discovery News
Fri, 05 Dec 2008 04:37 UTC
Image
© Soprintendenza per i Beni Archeologici dell'Emilia-RomagnaDecorator styles
Italian researchers have discovered the pottery center where the oil lamps that lighted the ancient Roman empire were made.

Evidence of the pottery workshops emerged in Modena, in central-northern Italy, during construction work to build a residential complex near the ancient walls of the city.

"We found a large ancient Roman dumping filled with pottery scraps. There were vases, bottles, bricks, but most of all, hundreds of oil lamps, each bearing their maker's name," Donato Labate, the archaeologist in charge of the dig, told Discovery News.
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Sun

Sun Induces Strange 'Breathing' of Earth's Atmosphere

Alexis Madrigal
Wired Science
Thu, 18 Dec 2008 04:08 UTC
San Francisco, California - New satellite observations have revealed a previously unknown rhythmic expansion and contraction of Earth's atmosphere on a nine-day cycle.

This "breathing" corresponds to changes in the sun's magnetic fields as it completes rotations once every 27 days, NASA and University of Colorado, Boulder, scientists said Monday at the American Geophysical Union annual meeting.
Image
The dark regions of the image indicate coronal holes.

The sun's coronal holes, seen as dark regions in the image above, direct plasma away from the sun and out into the solar system. When these particles get to the Earth, they heat the upper atmosphere, causing the outer atmosphere to expand and contract.
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Saturn

Tiny Saturn Moon ID'd As Good Candidate For Alien Life


Wired News
Thu, 18 Dec 2008 03:51 UTC
saturn moon
© nasa
San Francisco, California - Saturn's tiny moon Enceladus may be one of the best candidates for extraterrestrial life in our solar system.

Scientists for the first time have gathered comprehensive evidence suggesting Enceladus may have all the necessary ingredients to harbor life in the ocean beneath its icy crust.

Particles in a large plume of water vapor emanating from the surface suggest the moon has an active ocean that circulates life-sustaining nutrients picked up from the rocky interior below.
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Magnify

Asteroid may have caused New York tsunami 2,300 years ago


Entertainment and Showbiz!
Wed, 03 Dec 2008 02:49 UTC
Scientists have found new evidence suggesting a giant tsunami that crashed in New York City 2,300 years ago, was caused by an asteroid 330 feet in diameter, which slammed into the Atlantic Ocean nearby.

According to a report in Discovery News, Katherine Cagen of Harvard University and a team of researchers found clues in the form of slit in the Hudson River, which indicates an asteroid impact in the past.

While sifting through samples, the researchers found carbon spherules, which are perfectly round particles that form in the extreme pressures of an impact.

"But the main thing that closes the deal is that we looked in the spherules and found nano-diamonds," said Dallas Abbott of Columbia University, a co-author on the work. "These have only been found in impact ejecta or in meteorites," he added.
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