Science & TechnologyS


Question

What Shook Up Saturn's Rings in 1984?

Rachel Courtland
New Scientist
Wed, 14 Oct 2009 18:07 UTC
Image
© NASA/JPL/SSIInscrutable but not immutable
Saturn's rings seem almost immutable. These planetary jewels, carved by moonlets and shaped by gravity, could well have looked much the same now as they did billions of years ago - but only from afar.

Now it is emerging that an event around 25 years ago dramatically disrupted the rings - and all our telescopes and spacecraft missed it. This mysterious event suddenly warped the planet's innermost rings into a ridged spiral pattern, like the grooves on a vinyl record. The latest images reveal that the perturbation is so vast that only a profound change to the planet can have caused it.

The first hint that Saturn's rings had been perturbed came in 2006 from NASA's Cassini spacecraft, which took pictures of the planet's innermost ring, a tenuous, icy band called the D ring. Cassini found alternating light and dark bands that suggested the ring was not perfectly flat, but was composed of grooves, about a kilometre in amplitude.
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Magnify

What Drives Our Genes? Researchers Map The First Complete Human Epigenome


Science Daily
Wed, 14 Oct 2009 15:13 UTC
Although the human genome sequence faithfully lists (almost) every single DNA base of the roughly 3 billion bases that make up a human genome, it doesn't tell biologists much about how its function is regulated. Now, researchers at the Salk Institute provide the first detailed map of the human epigenome, the layer of genetic control beyond the regulation inherent in the sequence of the genes themselves.

"In the past we've been limited to viewing small snippets of the epigenome," says senior author Joseph Ecker, Ph.D., professor and director of the Genomic Analysis Laboratory at the Salk Institute and a member of the San Diego Epigenome Center. "Being able to study the epigenome in its entirety will lead to a better understanding of how genome function is regulated in health and disease but also how gene expression is influenced by diet and the environment."
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Binoculars

Hunting Arctic Asteroid Impact With Hovercraft

Alexis Madrigal
Wired
Mon, 12 Oct 2009 17:43 UTC
Two polar scientists hot on the trail of an arctic mystery have a new tool for exploration: a hovercraft, specially outfitted for week-long trips over the ice with scientific instruments and solar panels.

Hovercraft
© Hall and KristoffersonThe hovercraft
Their quarry is a nearly 22,000 square-mile patch of disturbed Arctic sea floor that could be evidence of a massive asteroid strike. John Hall, a now-retired geoscientist, discovered the anomaly during his late-'60s graduate work aboard Fletcher's Ice Island, a huge berg U.S. scientists inhabited for several decades.

Since then, no scientific vessel has been back over the area to collect more data. The massive icebreakers that have crunched through the Arctic since the 1990s can't reach the spot, said Yngve Kristofferson, a scientist and explorer at the University of Bergen in Norway.

Kristofferson became intrigued with Hall's data and in 2004, the two of them met in Bergen to talk Arctic science from eight in the morning to 10 in the evening. At the end of their time together, they came to a decision: They needed a hovercraft.
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Telescope

Scientists May Have Found First Direct Evidence of Water Ice on Asteroid's Surface


Thaindian News
Tue, 13 Oct 2009 14:32 UTC
Two independent scientific teams have found what may be the first direct evidence of water ice on the surface of an asteroid, a discovery that lends support to the idea that asteroids could have helped deliver water to the early Earth.

Asteroids are generally considered to be rocky, and comets icy. That's because ice in the early solar system is thought to have formed beyond a "snow line" lying somewhere between Mars and Jupiter.

Asteroids forming beyond that boundary could contain ice.

But, it is not clear how common ice might be in the main asteroid belt, because sunlight is expected to quickly vaporise ice on the surfaces of airless bodies that fly closer to the sun than Jupiter.

In 2008, however, Andrew Rivkin of Johns Hopkins University in Laurel, Maryland, and Joshua Emery of the SETI Institute in Mountain View, California, found hints that the asteroid 24 Themis, which sits in the main asteroid belt between Mars and Jupiter, could have water ice on its surface.
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Meteor

What Hit Earth in 1908 with the Force of 3,000 Atomic Bombs?


PhysOrg
Tue, 13 Oct 2009 00:00 UTC
The Tunguska Mystery
© Vladimir RubtsovThe Tunguska Mystery
There have been numerous theories proposed about what struck the taiga in central Siberia, causing millions of trees to topple over and many still-standing trees to lose all their branches. Many expeditions have looked for traces of what hit Earth and have not found much. There is no telltale meteor crater, and no clear evidence of a nuclear blast. In fact, at the epicenter, the trees were found to be still standing. Whatever hit Earth did not reach the ground. It exploded in the air above the ground.

In The Tunguska Mystery by Vladimir Rubtsov, the efforts put forth by generations of Russian scientists, technicians, and others are documented. What did they find? Was it a meteorite, as had first been thought? Was it an asteroid? Was it a comet? Some support the idea that this was not a "natural" event at all but one caused by the explosion of an alien spaceship trying to land on Earth. Is there any evidence for this? How did the Russian scientific and world community react to this theory?

The mystery has been very difficult to solve, but it is important - perhaps even urgent - to solve it. We live in a very violent universe, and we are extremely vulnerable to its vagaries. How can we prevent another "Tunguska" if we don't even know what it was? And next time, the event might not occur in a remote, barely inhabited region of Earth. It may take many thousands of lives and destroy whole cities.
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Sherlock

New York: Ancient Artifacts Found in Hudson Valley


The Associated Press
Tue, 13 Oct 2009 06:22 UTC
An archaeologist has found ancient tool fragments and other artifacts at the site of a suburban New York sewer construction project.

The find was made around Peach Lake, in the Putnam County town of Southeast.

Archaeologist Michael Pappalardo says the artifacts also include pottery shards; a 2 1/2-inch blade; tips for arrows or darts; and stone flakes that show tools were made there.

It's believed the artifacts are about 1,000 years old. They're being donated to the Southeast Museum in Brewster.

The dig was required by state and federal historic preservation acts.
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Sherlock

Possible New Da Vinci Painting Found

Rob Gillies
The Associated Press
Wed, 14 Oct 2009 12:31 UTC
Painting
© AP Photo/HO/Lumiere TechnologyThis undated photo provided by Lumiere Technology in Paris shows the site of the fingerprint on a painting that art experts believe they have identified as a new Leonardo da Vinci.
A new portrait by Leonardo da Vinci may have been discovered thanks to a centuries-old fingerprint.

Peter Paul Biro, a Montreal-based forensic art expert, said that a fingerprint on what was presumed to be a 19th-century German drawing of a young woman has convinced art experts that it's actually a Leonardo.

Canadian-born art collector Peter Silverman bought "Profile of the Bella Principessa" at the Ganz gallery in New York on behalf of an anonymous Swiss collector in 2007 for about $19,000. New York art dealer Kate Ganz had owned it for about 11 years after buying it at auction for a similar price.

One London art dealer now says it could be worth more than $150 million. If experts are correct, it will be the first major work by Leonardo to be identified in 100 years.

Ganz doesn't believe it is.
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Meteor

North America Comet Theory Questioned

Rex Dalton
Nature News
Mon, 12 Oct 2009 10:00 UTC
San Jon site
© Vance HollidaySediments at the San Jon site, in eastern New Mexico, contained very low abundances of magnetic spherules said to be evidence of an impact.
No evidence of an extraterrestrial impact 13,000 years ago, studies say.

An independent study has cast more doubt on a controversial theory that a comet exploded over icy North America nearly 13,000 years ago, wiping out the Clovis people and many of the continent's large animals.

Archaeologists have examined sediments at seven Clovis-age sites across the United States, and did not find enough magnetic cosmic debris to confirm that an extraterrestrial impact happened at that time, says the report in the Proceedings of the National Academy of Sciences (PNAS). It is the latest of several studies unable to support aspects of the impact hypothesis.

In 2007, a team led by Californian researchers announced a theory that a comet or asteroid had exploded over the North American ice sheet, creating widespread fire and an atmospheric soot burst followed by a cooling period known as the Younger Dryas.

Sometime after this, the Clovis people, sophisticated large-animal hunters known for their spear points, mysteriously disappeared; the team linked their vanishing to the environmental effects of the proposed impact.

Comment: For a more in-depth view, read: The Younger Dryas Impact Event and the Cycles of Cosmic Catastrophes - Climate Scientists Awakening

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Sherlock

New Ancient Flying Reptile Discovered


Scientific American
Wed, 14 Oct 2009 11:06 UTC
Flying
© Mark Witton/UP
The discovery of a new ancient flying reptile promises to answer questions - about the evolution of this species and others - that have been lingering since Charles Darwin's time.

The new 160-million-year-old pterosaur, named Darwinopterus in honor of the famed 19th-century naturalist, has emerged as an important middle specimen between early, long-tailed pterosaurs - also known as pterodactyls - and later short-tailed ones.

"We had always expected a gap-filler with typically intermediate features," David Unwin, of the University of Leicester's School of Museum Studies and a member of the research team that analyzed the fossils, said in a prepared statement. "Darwinopterus came as quite a shock to us." The new findings were published online today in the Proceedings of the Royal Society B.
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Blackbox

Out of your head: Leaving the body behind

Anil Ananthaswamy
New Scientist
Tue, 13 Oct 2009 20:38 UTC
Image
© Christian Lichtenberg/GettyPeculiar experiences
The young man woke feeling dizzy. He got up and turned around, only to see himself still lying in bed. He shouted at his sleeping body, shook it, and jumped on it. The next thing he knew he was lying down again, but now seeing himself standing by the bed and shaking his sleeping body. Stricken with fear, he jumped out of the window. His room was on the third floor. He was found later, badly injured.

What this 21-year-old had just experienced was an out-of-body experience, one of the most peculiar states of consciousness. It was probably triggered by his epilepsy (Journal of Neurology, Neurosurgery and Psychiatry, vol 57, p 838). "He didn't want to commit suicide," says Peter Brugger, the young man's neuropsychologist at University Hospital Zurich in Switzerland. "He jumped to find a match between body and self. He must have been having a seizure."

In the 15 years since that dramatic incident, Brugger and others have come a long way towards understanding out-of-body experiences. They have narrowed down the cause to malfunctions in a specific brain area and are now working out how these lead to the almost supernatural experience of leaving your own body and observing it from afar. They are also using out-of-body experiences to tackle a long-standing problem: how we create and maintain a sense of self.
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