A BALL spinning in a vacuum should never slow down, since no outside forces are acting on it. At least that's what Newton would have said. But what if the vacuum itself creates a type of friction that puts the brakes on spinning objects? The effect, which might soon be detectable, could act on interstellar dust grains.
In quantum mechanics, the uncertainty principle says we can never be sure that an apparent vacuum is truly empty. Instead, space is fizzing with photons that are constantly popping into and out of existence before they can be measured directly. Even though they appear only fleetingly, these "virtual" photons exert the same electromagnetic forces on the objects they encounter as normal photons do.
Now, Alejandro Manjavacas and F. Javier García de Abajo of the Institute of Optics at the Spanish National Research Council in Madrid say these forces should slow down spinning objects. Just as a head-on collision packs a bigger punch than a tap between two cars one behind the other, a virtual photon hitting an object in the direction opposite to its spin collides with greater force than if it hits in the same direction.
So over time, a spinning object will gradually slow down, even if equal numbers of virtual photons bombard it from all sides. The rotational energy it loses is then emitted as real, detectable photons.
The strength of the effect depends on the object's make-up and size. Objects whose electronic properties prevent them from easily absorbing electromagnetic waves, such as gold, may decelerate little or not at all. But small, low-density particles, which have less rotational momentum, slow down dramatically.
The rate of deceleration also depends on temperature, since the hotter it is the more virtual photons pop in and out of existence, producing the friction. At room temperature, a 100-nanometre-wide grain of graphite, the kind that is abundant in interstellar dust, would take about 10 years to slow to about one-third of its initial speed. At 700 °C, an average temperature for hot areas of the universe, that same speed decrease would take only 90 days. In the cold of interstellar space, it would take 2.7 million years.
Could this effect be tested in the lab? Manjavacas says the experiment would require an ultra-high vacuum and high-precision lasers to trap the nanoparticles, conditions that are "demanding but reachable in the foreseeable future".
Read more at New Scientist
Feb 12, 2011
Winter Halts Drilling Into 14-Million-Year-Old Lake
The team — headed up by the Russian Arctic and Antarctic Research Institute in St. Petersburg — had to call off work just 29 meters [95-foot] short of the end goal because the Antarctic winter is fast closing in. News that they plan to fill the 3,749-meter [12,300-foot] borehole with kerosene to prevent it from freezing will further trouble groups who fear continued research will contaminate the lake.
Alexei Turkeyev, chief of the Russian-run Vostok Station, told Reuters on Feb. 4: “It’s minus-40 [degrees Celsius, which happens to equal minus-40 Fahrenheit] outside. But whatever, we’re working. We’re feeling good.” Unfortunately Turkeyev and his team were forced to pack up last-minute amid fears they would be stranded. Temperatures above Lake Vostok fall to as low as 89 degrees below zero Celsius [minus 128 degrees Fahrenheit] during winter, the coldest recorded natural temperature on Earth.
The lake has been protected from the atmosphere and the other surrounding 150 subglacial lakes by a 4-kilometer-[2.5-mile] thick ice cap. What lies beneath the mammoth sheet of ice may provide answers to what Earth was like before the Ice Age and how life has evolved.
Most importantly, Lake Vostok appears to be incredibly similar to the frozen lakes of Jupiter’s Europa satellite and Saturn’s Enceladus. As Wired UK reported earlier this week, NASA and the ESA have already planned a joint mission to explore Europa’s lake in 2020. If life is found in Vostok, the implications for the possibility of extraterrestrial life on Europa and Enceladus are huge.
“It’s like exploring an alien planet where no one has been before,” said Valery Lukin of the Arctic and Antarctic Research told Reuters. “We don’t know what we’ll find.”
Drilling began in 1990 after satellite images revealed a series of subglacial lakes in the region, but work has been held-up several times amid concerns that progress could damage the previously untouched environment below.
“If Russia continues to drill, the lubricants and anti-freeze present in their borehole may taint the microorganisms they are trying to discover,” the Antarctic and Southern Ocean Coalition has argued.
Read more at Wired
Mysterious Manuscript's Age Determined
The dating, carried out last year but announced this week, makes the book a century older than scholars had previously thought and quashes some theories about its origin.
Taking its name from the rare book dealer Wilfrid Voynich, who discovered it in 1912 in the Villa Mondragone near Rome, the manuscript, which is about 250 pages long, makes "The Da Vinci Code" pale by comparison.
The book's estimated 250,000 characters are totally alien. Arranged in groups like words and sentences, some resemble Latin letters and Roman numerals; others are unlike any known language.
Moreover, the puzzling handwriting is surrounded by intricately drawn illustrations: plants that can't be identified, astrological symbols, elaborate networks of pipework, and naked ladies dancing or bathing in a strange green liquid.
"Who knows what's being written about in this manuscript. ... Just look at those drawings: Are they botanical? Are they marine organisms? Are they astrological? Nobody knows," said Greg Hodgins, an assistant research scientist and assistant professor in the University of Arizona's department of physics with a joint appointment at Arizona's School of Anthropology.
Working at the NSF-Arizona Accelerator Mass Spectrometry, Hodgins was able to solve one of the many mysteries about the book, nailing down the time when the manuscript's pages were made.
In order to carbon-14 date the book, which is currently kept at the Beinecke Rare Book and Manuscript Library of Yale University and accessible online, Hodgins used four one-sixteenth of an inch by one inch samples from four different pages.
"The four pages were explicitly selected from different sections to try to determine if the book was written over many decades," Hodgins told Discovery News.
Hodgins' team was able to determine that the samples were made between 1404 and 1438 -- quite a narrow range for a radiocarbon measurement.
"Nature worked in our favor. During the early 15th century, radiocarbon levels were changing quite rapidly, so that allowed us to narrow the time frame. Sometimes atmospheric radiocarbon levels remain constant for many decades, even centuries. And in those periods, radiocarbon dating is much less precise," Hodgins said.
According to the researchers, the dating is reliable, since it was repeated four times with independent leaves of parchment.
"It is important to realize that we date when the animal lived, not when the book was made. One can not say how much time elapsed between the death of the animal and when the writer put pen to page. The book was clearly a lot of work and must have taken several years to complete," Hodgins said.
The dating might help in ruling out some hypotheses.
Ever since Wilfrid Voynich made the manuscript public in the hope of having it translated, theories flourished about the book's author and content.
Voynich, which claimed the book had belonged to the 16th-century Habsburg emperor Rudolf II, believed it was authored by Roger Bacon, a 13th-century English friar and scientist -- a theory which carbon dating has put to rest.
Other speculations ranged from the manuscript being the secret work of a religious sect, the only remaining document from a forgotten language, an unbreakable secret code, and the recipe for the "elixir of life."
Several experts also proposed that it was a deliberate hoax, possibly forged by John Dee, an English mathematician and astrologer at Rudolph's court.
Indeed, in 2003 computer scientist Gordon Rugg demonstrated that text resembling that in the book could be generated with a Cardan grille, an encryption device invented around 1550.
Read more at Discovery News
Feb 11, 2011
Breath sensor predicts an asthma attack the day before
A HANDHELD breath sensor can warn someone with asthma that an attack is imminent, buying them time to take preventive medication, perhaps as much as 24 hours.
The breath sensor, developed by Siemens, measures telltale rise in levels of nitrogen monoxide. NO is produced naturally in the body, and can signal the beginnings of inflammation in the bronchial tubes. If unchecked, the inflammation will constrict the airways and trigger an asthma attack.
"Nitrogen monoxide (in the breath) indicates that the bronchial system is inflamed," says Siemens's Maximilian Fleischer, who helped develop the sensor. "This means there is danger of an upcoming asthma attack."
The sensor can detect levels of NO in the breath as low as 1 part per billion, but the higher the level the more severe the impending attack may be.
When the user breathes into the device's mouthpiece, the air first passes over a potassium permanganate catalyst, which converts any NO present into NO2. The air then flows over a film containing phthalocyanin, a blue dye which binds to the NO2 molecules, so that they stick to the surface of the film. This generates a voltage, which is detected by an underlying transistor. The strength of the voltage depends on the amount of NO2 present, which in turn equates to the NO levels and hence inflammation.
Read more at New Scientist
Fleas Jump Using Spring-Loaded Feet
sciencenewsNo, not rabbits or frogs. Fleas.
Using new tools like high-speed video, researchers with the University of Cambridge in England have shown that fleas take off from their tibia and tarsi — the insect equivalent of feet — and not their trochantera, or knees. The researchers report their conclusion in the March 1 Journal of Experimental Biology.
Regardless of how fleas do it, the insects have always been famous jumpers, says study co-author Gregory Sutton. “There are even fairy tales that talk about how magnificent fleas are at jumping,” he says. And it’s not surprising: Fleas jump far. Some fleas — only a few millimeters long — can jump well over 10 centimeters, according to one study. Adult hedgehog fleas (Archaeopsyllus erinacei) go from resting to midair in about 1 millisecond, says Sutton, a mechanical engineer at Cambridge.
No known muscle can generate anywhere near the power needed to launch a flea so far, Sutton says. In the late 1960s, researchers discovered that the bugs aren’t jumping with just their muscles. Instead, they spring. Before fleas launch, they store energy in a naturally springy protein hidden away in their bodies called resilin, then release it in one big bound.
But where the spring power goes from there wasn’t clear. One camp said the force moves down to the knees, the other said the feet. “They argued about it,” Sutton says, and for years the technology didn’t exist to put the matter to rest.
It did, however, for Sutton and biologist Malcolm Burrows. With a little “flea wrangling,” the researchers were able to collect 51 slo-mo clips of leaping hedgehog fleas.
The St. Tiggywinkles Wildlife Hospital Trust in Buckinghamshire, England, donated the fleas right off the backs of hedgehogs, the researchers note. The team also drew up mathematical models to simulate bug leaps on paper and eyed flea anatomy up-close using a scanning electron microscope.
Read more at Wired
Lucy, Early Human Ancestor, Walked Upright
The bone belongs to a cohort of the famed hominid Lucy, whose species Australopithecus afarensis roamed eastern Africa, and is the first evidence to address the question of how they got around.
"This fourth metatarsal is the only one known of A. afarensis and is a key piece of evidence for the early evolution of the uniquely human way of walking," said study co-author William Kimbel of Arizona State University.
An arch in the foot would provide leverage to push off the ground at the start of a stride and then help absorb shock when the foot meets ground again, suggesting Lucy's feet were much like ours.
Apes have flatter, more flexible feet with a big toe for grasping tree branches, attributes that do not appear in the A. afarensis.
"Understanding that the foot arches appeared very early in our evolution shows that the unique structure of our feet is fundamental to human locomotion," said co-author Carol Ward of the University of Missouri.
Read more at Discovery News
Feb 10, 2011
Jerusalem UFO video debunked
Here’s the original video that’s been circulating with more here.
It’s pretty cool, but an obvious hoax. Imagine you’re standing late at night videotaping the scene with a friend because it’s so pretty. Out of nowhere a bright light comes down out of the sky, hovers over one of the most famous temples on the planet, then flashes brilliantly and shoots straight up at fantastic speed.
Would you just stand there like a lump without showing any reaction at all, like the guy in the video?
Also, it seems a little weird that such an incredibly bright object could hang over this heavily visited site, even in the middle of the night, and there were no reports of any eyewitnesses. Just one video that turns up, and a few days later a couple more. Seriously?
And now this video has been conclusively shown to be faked.
It’s pretty cool, but an obvious hoax. Imagine you’re standing late at night videotaping the scene with a friend because it’s so pretty. Out of nowhere a bright light comes down out of the sky, hovers over one of the most famous temples on the planet, then flashes brilliantly and shoots straight up at fantastic speed.
Would you just stand there like a lump without showing any reaction at all, like the guy in the video?
Also, it seems a little weird that such an incredibly bright object could hang over this heavily visited site, even in the middle of the night, and there were no reports of any eyewitnesses. Just one video that turns up, and a few days later a couple more. Seriously?
And now this video has been conclusively shown to be faked.
Walking improves your memory
One group walked around a track three times a week, building up to 40 minutes at a stretch; the other did a variety of less aerobic exercises, including yoga and resistance training with bands. After a year, brain scans showed that among the walkers, the hippocampus had increased in volume by about 2 percent on average; in the others, it had declined by about 1.4 percent. Such a decline is normal in older adults.
For the full article visit the glorious Deric Bonws’ Mind Blog
Feb 9, 2011
Homeopathy's Ineffectiveness Saves Lives
They gathered in 25 countries (in an event known as "The 10:23 Campaign") and took massive overdoses of medication -- not to harm themselves, but to prove a point. No one suffered ill effects because the medications were homeopathic, have no active ingredients, and are therefore worthless. Real drugs of proven efficacy can be dangerous or lethal in high enough doses; homeopathic remedies cannot.
In January 2010 Alexa Ray Joel (daughter of Billy Joel) tried to overdose on a homeopathic medication in an apparent suicide attempt. She, also, was just fine.
Skeptical and scientific organizations have long decried ineffective and alternative medicines. D.J. Grothe, president of the James Randi Educational Foundation which participated in the event, said he hoped to educate the public about homeopathy.
"We believe consumers deserve the truth about homeopathic products," he told Discovery News. "Most have no active ingredients whatsoever, they've been proven not to work any better than plain water or sugar pills, and they aren't tested or approved by any U.S. health agency. Using fake medicine to treat real health problems can be dangerous. When parents need something to help their child's cough or break a fever, they trust that what they get from their drugstore is real medicine."
Homeopathy was invented around 1796 by a doctor named Samuel Hahnemann. He believed that homeopathic medicines become more effective the more they are diluted. Homeopathic solutions are often so literally watered-down that they don't contain a single molecule of the original medicine or substance: the patient is drinking nothing but water. Homeopathic medicines have not been shown to work better than placebos, yet many people use and endorse homeopathy.
Last year the British Science and Technology Select Committee conducted a comprehensive study into whether homeopathy has any scientific validity. The report was devastating: "homeopathy is not efficacious, and explanations for why homeopathy would work are scientifically implausible." Even professional homeopathic practitioners admitted that basic claims made about homeopathy have never been tested nor proven.
Homeopathic practitioners insist that homeopathy works, and that anyone who says otherwise is either misinformed or secretly lobbying for the pharmaceutical industry (never mind that homeopathic remedies are a half-billion-dollar industry).
You can test the homeopathic principle yourself easily at home: The next time you reach for a pain reliever, instead of swallowing the pill, crush it, pick out a few of the smaller crumbs of medicine, and take those. According to homeopathy, the less you take of the medicine, the more effective it will be.
Read more at Discovery News
Tree Rings Reveal Drought's Role in Mexican History
A new study, which used tree rings to add many hundreds of years to the region's climate record, pinpointed four severe droughts in the region over the last 1,200 years. Some were far more intense and prolonged than anything ever seen in modern meteorological records, and many coincided with major historical events.
One, for example, lasted for 25 years around the year 900 and accompanied the end of a flourishing era of Mayan city-states.
By dating droughts to precise periods of time, the work puts the region's current drought problems into perspective, said David Stahle, a geoscientist at the University of Arkansas, Fayetteville. The findings should also help researchers figure out the factors that have driven moisture out of the area again and again throughout history.
"Clearly the drought in 1400 was not caused by the accumulation of heat-trapping gasses in the atmosphere because it precedes the industrial revolution," Stahle said. "But something caused it that stimulated very unusual climate conditions elsewhere in the world. This may allow us to determine the dynamics of drought-forcing over Mexico."
There are at least two points of view about the links between climate and culture, Stahle added. And controversy surrounds the conversation.
"Books have been written asserting the point that droughts ended civilizations," he said. "Others say that's too simplistic. The fact remains that there were these physical events in the environment. Surely, that had some kind of consequences."
Whatever the implications, simply piecing together the ancient climate history of Mesoamerica fulfills a long-standing goal in the field of tree-ring analysis, Stahle said. Until now, studies have been able to look back only about 500 years.
As a result, researchers could only speculate about how climate change may have affected a series of highly developed cultures, whose accomplishments included huge pyramids and elaborate temples.
To extend the record, Stahle and colleagues plunged through rugged terrain into a steep gorge at Barranca de Amealco. The gorge sits about 90 kilometers (56 miles) north of Mexico City. It is 60 km (37 miles) from Tula, the capital city of the ancient Toltec state, and 90 km (56 miles) from the Aztec capital of Tenochitlan.
Although surrounding areas have been deforested and developed, the gorge has held onto a grove of gargantuan Montezuma baldcypress trees that span as wide as four meters (14 feet) in diameter. Without harming any trees, the researchers drilled and removed hundreds of meter-long cores. They analyzed 74 of the cores, which were about the thickness of a pencil, from 30 trees.
By comparing annual growth rings between samples, the researchers were able to look back at the region's climate, year by year, going back 1,238 years. The thickness of a given ring reveals how dry or wet a single growing season was.
According to their analyses, one of the most severe periods of drought occurred between 897 and 922, the researchers reported in the journal Geophysical Research Letters, just as the Terminal Classic period came to an end. Another 19-year drought around 1150 coincided with the fall of the Toltec state, which was the dominant civilization of central Mexico at the time.
Read more at Discovery News
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