Thursday, August 23, 2007

"Cosmic Train Wreck" May Derail Theories of Dark Matter



New observations of a massive intergalactic collision are raising more questions about the mysterious nature of dark matter.

The study looked at three huge galaxy clusters that are merging into an even bigger cluster called Abell 520, located about three billion light-years from Earth.

Astronomers describe the collision as a "cosmic train wreck," given the immensity of the forces involved. Each cluster contains about a thousand galaxies, and each galaxy has billions of stars.

The new findings show an unprecedented mix-up in the merging clusters, suggesting the need for an "uncomfortable" revision—or entire rewrite—of our current theories of dark matter.

"Whatever happened did something really unusual to the galaxies," said study lead author Andisheh Mahdavi, an astronomer at the University of Victoria in British Columbia, Canada.

"It moved them all the way on the outer edge of the central region of the cluster, so that only gas and dark matter is left at the center," he added.

"That's never been observed before, and it's really hard to explain."

The findings are slated to appear in an upcoming issue of the Astrophysical Journal.

Mysterious Matter

Dark matter does not absorb or emit light, but scientists believe it makes up about 90 percent of the matter in the universe.

Prevailing theories hold that dark matter is composed of particles that have very weak interactions and move only under the influence of gravity, just like stars.

So when galaxies collide, scientists expect stars and dark matter to move together. Intergalactic gas, however, also responds to pressure and thus is expected to lag behind the other matter.

The bullet cluster observations show dark matter and stars moving together and ahead of the intergalactic gas.

But when Mahdavi and colleagues studied Abell 520, they found a dark matter core separated from most of the galaxies.

Eye in the Sky

Mahdavi and colleagues mapped the distribution of matter in Abell 520 with two ground-based optical telescopes in Hawaii and the orbiting Chandra X-Ray Observatory

Optical telescopes determine the location galaxies from their starlight and infer the location of dark matter by the way its gravity bends the light of other galaxies in the distant background, a technique called gravitational lensing.

X-ray telescopes detect the radiation given off by scorching hot intergalactic gas.

Mahdavi and colleagues plan to re-observe Abell 520 with the Hubble Space Telescope later this year, which will allow for more precise mapping of the dark matter.

If the Hubble observations confirm the distribution of matter in the cluster, astronomers may be forced to revise the physics used to explain the behavior of dark matter, Mahdavi said.

"Uncomfortable" Explanations

There are two possible explanations, "and they're both equally uncomfortable," Mahdavi said.

The galaxies may have been flung to the outer edge of the cluster via a gravitational slingshot, in the same way astronomers can send satellites around a nearby planet for an extra push to the outer solar system.

"But that has a number of problems, in that we haven't been able to make [with computer simulations] slingshots that are powerful enough," Mahdavi said.

The other possibility is the dark matter just got left behind as the galaxies passed on through the center of the cluster, suggesting that the dark matter interacted through some force other than gravity.

"The problem with that is this is not the theory of dark matter that's generally accepted," he said.

The bullet cluster observations, for instance, appear to confirm the accepted theories that dark matter contains only weakly interacting particles.

Wait and See

Avi Loeb is an astronomer at Harvard University in Cambridge, Massachusetts, who was not involved in the study.

He said he will wait for the results of the Hubble observations "before making a judgment whether the nature of dark matter might be different."

If the result is confirmed, researchers will probably try to explain the phenomenon via the gravitational slingshot effect, which is more plausible than completely revising the physics, Loeb said.

"I don't think we should revise our ideas just based on this example, because there is also the bullet cluster that is showing a different picture and clearly the circumstances are different in the two clusters," he said.

Additional studies of other galactic collisions will help firm up conclusions about dark matter, Loeb added.

"At the moment, we have just two examples of these natural laboratories for dark matter dynamics," he noted.

Weird Deep-Sea Creatures Found in Atlantic




World's Oldest Diamonds Discovered in Australia


The world's oldest known diamonds have been found encased in a crystal in Western Australia.The minuscule gemstones are 4.25 billion years old and could provide a rare glimpse into Earth's distant geologic past.

"No one would have really predicted that diamonds were in there," said Simon Wilde, a geologist at Curtin University of Technology in Perth and a member of the team that made the find.

The discovery suggests that seas of molten lava that covered primordial Earth had cooled down faster than had previously been thought.

The find also suggests that plate tectonics, the process by which large shelves of Earth's crust move to create geologic activity, may have already been underway.

"A diamond would never form in a magma ocean," said Thorsten Geisler, a geologist at Westfalische Wilhelms-Universitaet in Munster, Germany, and another team member.

The discovery is a shocker to geologists, many of whom believed that the molten lava and volcanic activity persisted on Earth's surface for at least 500 million years after our planet formed some 4.5 billion years ago.

Diamonds Are Forever

The tiny diamonds were found trapped in zircon, a rare and exceptionally stable mineral that forms under temperatures between 1,112 and 1,652 Fahrenheit (600 and 900 degrees Celsius).

Once zircon has crystallized it may be moved around by geological processes, but its chemical makeup and structure don't change. This makes its age easy to pinpoint.

Zircon crystals represent the only record of the first 400 million to 500 million years of Earth's history, Wilde explained.

By analyzing a crystal's trace minerals and structure, geologists can deduce the conditions under which it formed.

John Valley, a geologist at University of Wisconsin in Madison who was not involved in this study, notes that there are four known "recipes" that create diamonds.

But the 4.25-billion-year-old diamonds "suggest the additional possibility that the diamonds have formed by some process that is not yet understood."

Study co-author Wilde said, "The bottom line is that we really honestly don't know why they're there."

The study, led by Martina Menneken, a master's student at the Westfaelische Wilhelms-Universitaet, appears in this week's issue of the journal Nature. Alexander Nemchin from Curtin University of Technology also contributed.

Clues to Earth's Earliest Life?

One exciting prospect is that if Earth cooled down earlier in its existence, then it's possible that life on Earth cropped up earlier too, Geisler said.

(Related: "Weird Australia Rocks Are Earliest Signs of Life, Study Says" [June 7, 2006].)

Geisler hopes that analyzing the various types of carbon in these diamonds could reveal whether this was the case.

"We don't know yet, but this is potential information contained in the carbon," he said.

Valley, the Wisconsin geologist, added, "Even though these diamonds are too small to be of commercial value as gems, scientists will find them even more valuable for the information they carry about the Earth."

Wednesday, August 22, 2007

Vampire Bats Attacking Cattle as Rain Forest Falls


Vampire bats in Latin America are turning their fangs on cattle as rain forest is being cleared to make way for livestock, new research shows.

Scientists made the find by studying changes in the breath of vampire bats in Costa Rica.

The researchers discovered that the bats are finding meatier victims to sink their fangs into as the habitat of wild forest mammals disappears and is turned into livestock pasture.

A study led by Christian Voigt from the Leibniz Institute for Zoo and Wildlife Research in Berlin, Germany, found the blood-seeking bats are switching to cattle from rain forest prey such as tapirs and piglike peccaries.

The study team investigated which animals the bats were targeting by analyzing the chemical signatures, called isotopes, in the carbon dioxide they exhaled soon after eating.

Cattle and rain forest mammals feed on different plants that can be distinguished by their carbon isotopes. Since these chemical clues are present in prey's blood, the signature in the bats' breath varies with their meals.

The study clearly indicated that the vampires' most recent victims were almost always cattle, the team said.

The findings don't mean that vampire bats prefer bovine blood, the team said. Instead, they suggest that livestock are simply easier for the bats to find.

Voigt compared the vampire's dining options to that of a hungry human looking for a hot dog.

"One supplier is moving with a small van through the streets of the town, and it is not predictable for you where the van shows up," he said.

"The other supplier is in a snack bar with a permanent address. You most likely wouldn't go searching [for] the hot dog van but [would instead] go to the snack bar. Vampires are basically doing the same."

The research, which is published online in the Journal of Comparative Physiology B, came in response to reports from Costa Rican cattle ranchers of increased vampire attacks in the region.

Only three bat species are vampires, all of which are confined to Latin America. Just one of these, the common vampire bat, feeds on mammal blood.

Attacking at night, the bat doesn't suck its victims' blood but laps it up from tiny puncture wounds made with two sharp fangs. An anticoagulant in the bat's saliva keeps its nutritious meal from clotting.

Anecdotal evidence suggests that vampire bat numbers have increased significantly over the past 50 years, Voigt said.

This rise is widely attributed to deforestation, a theory bolstered by recent surveys of bat populations conducted by Voigt's team, he added.

A survey in virgin rain forest in the remote Amazon detected only a few vampires, Voigt said, but a survey of disturbed rain forest in the Andean foothills showed the winged blood-seekers to be the most abundant bat species.

No livestock were found near the Amazonian site, Voigt said, "whereas at the other site numerous pastures with cattle were present."

Livestock farming is seen as a leading cause of rain forest destruction in Central and South America.

(Related: "Amazon Deforestation Drops 25 Percent, Brazil Says" [August 14, 2007].)

In the Amazon, around 60 percent of deforestation between 2000 and 2005 can be attributed to cattle ranching, according to estimates based on figures from the Brazilian National Institute of Space Research and the United Nations Food and Agriculture Organization.

Rabies Threat

The growing number of vampire bats in cattle-ranching areas has also been blamed for the spread of disease among both humans and domesticated animals.

In just two months in 2005, 1,300 people in northern Brazil were treated for rabies after suffering bat bites. Twenty-three of the patients died, according to reports.

Voigt said that habitat conservation, along with efforts to reduce wildlife poaching, is crucial to minimizing the overall impact of vampire bats and their late-night raids.

"If rain forest mammals such as tapirs and peccaries are … killed, there is no alternative left for vampires to get blood from," he said.

Change the shape of frying pan

Tuesday, August 21, 2007

New Pepsi Advertisement

Turbo Parking

Chips Everywhere


Over the last 30 or so years,British entrepreneur Hermann Hauser has backed about 100 ideas,including three companies that have hit the billion-dollar mark.Plastic Logic,a Cambridge-based outfit launched six years ago,now seems to be shifting into high gear.Earlier this month it announced that it had raised $100 million to buld its first plan in Dresden,Germany.Its plan:to massproduce plastic semiconductors for the first time.If the venture is successful,it could undermine the dominance of the silicon chip that has become almost synonymous with high-tech revolution.

Thursday, August 9, 2007

Food For Thought

Claudia Roden is a Francophone Egyptian Jew whose ancestors were spice traders,and she's a one-woman window on the Middle East.Her new cookbook,"Arabesque:A Taste of Morocco,Turkey,and Lebanon,"offers fresh insight on a region many view in terms of politics and religion.With 150 recipes and dozens of essays on unfamiliar ingredients and customs,"Arabesque" whisks the reader through history,from the ancient Phoenicians to the kitchens of the Ottoman sultans,from ninth-century Baghdad to the Lebanese civil war in the late 1970s and '80s.For example:couscous,she writes,was brought from Ethiopia to North Africa in the seventh century by conquering Arab armies,perfected by Berbers and was recently voted the most popular dish in France,There's also a brief taste of politics:among both Palestinians and Israelis the subject of falafel can spark debates as vehement as those about Jerusalem.

Wednesday, August 8, 2007

Renault Is The Safetiest Car

Funny Kongfu Baby

First Time Be The Father

Lifting The Lid


Where can you find a Saudi break dancer,a Lebanese temptress and a narcoleptic sheik?At Ikbis,a new website that lets Arabs join the file-sharing craze.Internet use in Middle East has increased fourfold in the past six years,with more than 20million logging on each day.The first Arabic language service of its kind,Ikbis has already struck a chord-more than 1000 files went up within a week of its November launch,and the site now tops 30000 page views a day.Like YouTube,Ikbis attracts humorous clips.Ikbis's creators say they hope to provide a public forum for a region where a tight lid is kept on public expression."I think we're all,globally,just starting to understand the power of these digital tools,"says Ahmad Humeid,an Amman based graphic designer and one of the site's founder.

Tuesday, August 7, 2007

The Nobel Exception

The Nobel Prize is a lot more than a medal.Winners get $1.4million and the world's best resume line.Here's another thing to life under"life's nor fair":Nobel winners also live longer.New research from the University of Warwick says that academics who get the fateful phone call from Sweden stick around about two years longer than colleagues who don't make the final list.The effect mirrors what's been seen before in Oscar winners,whose life spans grow with every statue they take home.Since only four people have ever won multiple Nobels,though-and one,Marie Curie,had a short life because of her prizewinning work on dangerous radiation-the researchers couldn't document a truly identical trend.Still,they were able to figure out that,as with Oscars,it wasn't the cash that did the trick.Apparently,the key to long life among Nobel laureates was simply having the bragging rights.
The research has some lessons for mere mortals,too:it throws new light on an ongoing argument about why people of high social status tend to live longer,regardless of how much health care they get.One theory holds that winners-of prizes,but also in the game of life-are so buoyed by their achievements that their brains are"buffeted against any subsequent adversities",says the University of Toronto's Donald Redelmier,who studies the Oscar phenomenon,In other words,stress doesn't bother there folks as much.Redelmeier's won explanation?After you're reached the pinnacle,you'd be quite disinclined to be seen drunk in public if you've got a Nobel Prize,"he says.Unless,of course,you're tipsy from a little celebratory champagne of,for that matter,a toast to your longevity.

Thursday, August 2, 2007

World's Largest Carpet Woven for Worshippers


August 1, 2007—By any measure, it's a marvel—as a work of art, as an article of devotion, as a testament to the richness of hand-made craftwork. But who's going to take it outside and beat it?

Authorities in Iran unveiled what they described as the world's largest hand-woven rug yesterday at Tehran's open-air prayer grounds.

At 60,546 square feet (5,625 square meters), the carpet is the size of a soccer field and was woven by 1,200 weavers in three villages over the course of a year and a half.

The mammoth floor covering is destined for a monumental new mosque under construction in the United Arab Emirates. Emirati officials commissioned Iran's state-owned rug manufacturer to create the piece for the central prayer hall of the giant Sheikh Zayed mosque, slated to open this fall in the capital city of Abu Zaby (Abu Dhabi).

Weavers in Iran's northwestern Khorasan Province used 38 tons of wool and cotton from Iran and New Zealand to fashion the colorful covering, tying a staggering 2.2 billion knots in the process.

Half of the commission, estimated at 5.8 million U.S. dollars, will go to the villagers. But authorities hope that in addition to the income, the huge rug will bring renewed publicity to Iran's flagging carpet-weaving industry.

Long known for its delicate and ornate Persian rugs, Iran has recently been losing market share to cheaper Asian manufacturers, according to industry reports.

Aphrodite to Leave California



But the Victorious Youth stays in Malibu, as the Getty Museum gives Italy some—but not all—of the antiquities the government has demanded be returned.

Aug. 1, 2007 - The Getty Museum in Malibu, Calif., home to one of the finest collections of Greek and Roman art in the U.S., agreed Wednesday to return 40 of its prized ancient artworks to Italy. The dispute between the Italian government and the Getty has been roiling for more than two years and has led to the ongoing trial in Rome of a former Getty curator, Marion True, on charges of buying art for the museum that was looted and illegally exported from Italy. True has denied the charges.

Negotiations between the Getty and the Italians over the return of certain artworks stalled last November but were jump-started last month, when Italy issued a threat to sever all cultural ties with the Getty unless they came to terms by Aug. 1. (As the Los Angeles Times pointed out, this could have hurt the Italians more than the Malibu museum, as the Getty foundation gives hefty grants to Italian cultural causes and cooperates in scholarship and conservation.) Now the museum has agreed to send back 40 pieces from its collections, in exchange for loans of ancient art from Italy. Italian officials struck similar deals last year with the Museum of Fine Arts in Boston and the Metropolitan Museum of Art in New York.

The centerpiece of the returning treasure trove is a seven-foot-high marble-and-limestone statue of Aphrodite. The mammoth fifth-century B.C. goddess is thought to have been looted from the site of an ancient Greek settlement in Sicily. The Getty bought it for $18 million in 1988 from a London dealer, who claimed it had belonged to a Swiss family since 1939—a handy date, since that’s the year Italy passed a law barring the export of antiquities. The return of Aphrodite and the other prizes ends an embarrassing episode for the Getty—which has stringently tightened its acquisition standards—and is a triumph for the current Italian minister of culture, Francesco Rutelli.

Italy has one of the strictest laws governing its cultural property, and Rutelli has made political hay in his quest to get American museums to hand back suspect pieces. In early July, Rutelli issued his threat of a cultural embargo against the Getty in a speech at the city of Fano on the Adriatic coast. That’s the port where fishermen in 1964 came home with an amazing fourth-century B.C. bronze statue of a youth, caught in their nets. Locals have clamored for its return—but it’s in the Getty, which bought it in 1976, legitimately, the museum says. And here’s where the whole issue of cultural property gets so tricky. The fishermen found the statue in international waters—and it’s not Roman; it’s Greek. The Italians who first sold the statue were twice cleared of wrongdoing by Italian courts. Italy, which once made the return of the bronze statue the dealbreaker with the Getty, says it is continuing to investigate the statue’s provenance. The Victorious Youth, as it’s also known, is not part of the Getty’s agreement with Italy. It’s staying put in Malibu, a victory for the Getty—and for everyone who believes the patrimony of ancient cultures belongs, in a sense, to all of us.

Here Be Monsters


Dragons, sea serpents and manatees, er, mermaids—a museum show looks at the all-too-human impulse to embellish nature.

July 31, 2007 - At first, it's a bit of a mystery why the humble and homely manatee was included in an exhibit of fantastical creatures, both real and imagined. Some visitors might not even notice the shapeless gray form dangling from the ceiling, what with the 17-foot dragon just behind her and a stunning white unicorn standing on a pedestal just ahead of her. Nonetheless, the matronly sea mammal might be the most evocative item at the American Museum of Natural History's "Mythic Creatures: Dragons, Unicorns and Mermaids" exhibit in New York City.

Under the manatee, there's a small video screen on a stand. Twist a knob on the device and an image of the manatee slowly becomes a pretty mermaid. It's kind of like watching a bloated Marlon Brando morph into Angelina Jolie. You can't imagine how anyone could confuse the two—even at distance and even after months at sea eating nothing but salted meat. But somehow, the minds of 15th-century sailors turned these lumpy creatures into alluring women with fish tails who called to them from rocky shores. Or at least that's what they told everyone when they got home. Such is the human need to embellish nature and turn the ordinary into the extraordinary. And that's what the exhibition is all about.

Cocurator Laurel Kendall says she considers this collection of cultural artifacts, bones and theatrical renditions of imaginary animals a continuation of the museum's exhibits on human evolution—a testament to "the unique ability of humans to tell stories, to exaggerate."

The exhibit, which took two years to create, is divided into land, air and sea; and for each legendary creature, there is an anthropological history of how the myth evolved, filled out by illustrations, models and costumes. Real animals are displayed alongside the mythic. The dim, dappled lighting in the exhibit is intentional, says Kendall: "We really wanted to distinguish this from the rest of the museum."

There are animals you are sure couldn't have existed, but did, such as the Gigantopithecus blacki, a towering King Kong-like primate that stands taller than a man and has humanoid features. It looks like an artist's rendition of Bigfoot until you read the tag and find out it lived in Southeast Asia (and is now extinct).

Then there are taxidermied animals that seem authentic, but are part of a long line of hoaxes, like the desiccated corpse of a small fish creature with arms and a round skull. It should be a missing evolutionary link, but it's just a tiny monkey's torso glued to a papier-mâché fishtail. In the mid-19th century, P. T. Barnum advertised this creature, or something like it, as a "Feejee Mermaid." Of course, the posters showed a gorgeous nymph, not the wizened Franken-fish visitors were confronted with once they paid their admission.

And don't think for a second that the modern public is any less fixated on the idea of beings that we haven't yet been able to catalog and explain. "We mapped the world, now there's a lament for the unknown," says Kendall. So we fill in the blank spaces with imagined aliens from other universes or cling to old mysteries like the Loch Ness monster.

While our collective imagination hasn't let up, kids (and adults) now find their mythic creatures on their computers more often than not. They create Neopets and other virtual animals online and invest them with human qualities.

And if a Jules Verne-style animal surfaces, as it did earlier this year when a New Zealand fishing boat caught a 33-foot colossal squid off the coast of Antarctica, the public is utterly fascinated. A mythic squid is included in the exhibit. It's called a kraken, and its head and arms rise partway from the floor of the museum as if it were emerging from the sea. Nearby there are small photos of real giant squids to remind us that sometimes the tallest tales aren't that far off.

The museum says the exhibit, which is slated to go on a world tour after it closes in New York on Jan. 6, has been a rousing success. In the peak summer period, about 300,000 people stream through the museum each month, and the $21 tickets for this exhibit usually sell out every day by early afternoon. And why wouldn't they? In the age of Harry Potter and Eragon, what could be more enticing to families traipsing the hot streets of the city than looking at unicorns and dragons in air-conditioned comfort?

Of course, the show does at times seem to pander to a topic that is popular and lucrative. After all, visitors are funneled out past the Chinese dragon into a slickly designed gift shop brimming with Disney mermaids and Harry Potter figurines. Not to worry: after navigating the trinkets, you wind up in a spectacular sunlit hall of dinosaurs, where their massive bones belittle all of our imaginations.

Jaws, Teeth of Earliest Bony Fish Discovered




Fossils of sardine-size fish that swam in ancient oceans are the earliest examples of vertebrates with teeth that grow from their jawbones, according to new a new study.

The fish, which lived 420 million years ago, are a "very modest" beginning for the jaw-and-tooth pattern widespread in nature today, said study co-author Philippe Janvier, a paleontologist at the National Museum of Natural History in Paris, France..
"It's really the first evidence that we have of the earliest bony fishes—the earliest ancestors of all the fishes that have the[ir] bones and teeth implanted in the bones of the jaw," Janvier said.

Modern bony fish such as cod, herring, and coelacanths have this tooth arrangement. So do tetrapods—four-limbed creatures such as frogs, crocodiles, and humans, which are all descendants of bony fishes.

When a bony fish or a tetrapod loses a tooth, a new one grows from the bone below the void, whereas other jawed vertebrates, such as sharks, have teeth that grow from inside their gums. Sharks have skeletons of cartilage instead of bone.

Shark teeth are lined up in "families." New teeth grow at the inner end of their respective tooth family, and old teeth fall off at the end of an inside-out progression—similar to a conveyor belt.

Though fossil representatives of the earliest members of each of these living groups are well known, the earliest stages of jawed vertebrate evolution presents a fuzzier picture.

The new fossils help clarify these questions, Janvier said.

Transition Fossils

The researchers discovered the telltale bony fish fossils among fragments collected on the Swedish island of Gotland in the Baltic Sea. Other fragments came from boulders carried to Germany by glaciers a few million years ago.

Some of the fossils belong to the species Andreolepis hedei and others to Lophosteus superbus, fish previously identified by scale and head bone specimens.

Whether they were truly bony fish or more like sharks was an open question, however.
Two of the new fossils suggest a direct link to bony fish: tooth-bearing jawbones.

What's more, the bones show a tooth pattern that is in between the tooth rows of sharks and bony fishes.
Though these ancient bony fish teeth grew from a bone, old teeth remained attached to the bone. New, larger teeth grew at the inner end of each tooth file.

"It shows a sort of transition between the shark condition and the bony fish condition," Janvier said.
Within 20 million years after Andreolepis hedei and Lophosteus superbus lived, the first bony fish with much larger teeth characteristic of modern bony fish and tetrapods appear in the fossil record. This was during the Devonian period, 416 to 359 million years ago.
"That's very important because it allowed the bony fishes to become predators," Janvier said.

Sharks also existed in the Devonian, but they were "humble compared to the bony fishes," he said.

The first bony fishes probably ruled the seas, rather than sharks, because the bony fishes' teeth lasted a longer time in the jaw.

"Then, later on, the sharks ... became much larger and big predators," Janvier added.

The study appears in tomorrow's issue of the journal Nature.

Sorting Characteristics

Michael Coates, a biologist at the University of Chicago in Illinois who studies early vertebrate evolution, was not part of the research team.

He said the discovery of rare fossils like the ancient bony fish allows scientists to sort general, primitive characteristics of all jawed vertebrates from the more specialized features that distinguish sharks from bony fishes.

The new study, he noted, clearly shows that Andreolepis and Lophosteus are bony fishes, but their tooth pattern raises a question about what makes a shark a shark.

"Growing teeth in this serial manner around the jaw margin—which once upon a time looked like it was unique to sharks—now looks like it is a general system."