Wednesday, May 28, 2008

May 28, 585 B.C.: Predicted Solar Eclipse Stops Battle

A total solar eclipse 26 centuries ago brought a long war to an abrupt halt.

585 B.C.: A solar eclipse in Asia Minor brings an abrupt halt to a battle, as the warring armies lay down their arms and declare a truce. Historical astronomy later sets a likely date, providing a debatable calculation point for pinning down some dates in ancient history.

This was not the first recorded solar eclipse. After failing to predict one such in 2300 B.C., two Chinese astrologers attached to the emperor's court were soon detached from their heads. Clay tablets from Babylon record an eclipse in Ugarit in 1375 B.C. Later records identify total solar eclipses that "turned day into night" in 1063 and 763 B.C.

But the 585 B.C. eclipse was the first we know that was predicted. The Greek historian Herodotus wrote that Thales of Milete predicted an eclipse in a year when the Medians and the Lydians were at war. Using the same calculating methods that predict future eclipses, astronomers have been able to calculate when eclipses occurred in the past. You can run the planetary clock in reverse as well as forward. To coin a word, you can postdict as well as predict.

The most likely candidate for Thales' eclipse took place on May 28, 585 B.C., though some authorities believe it may have been 25 years earlier in 610 B.C. Hundreds of scholars have debated this for nearly two millenniums.

Predicting a solar eclipse is not easy. You need to calculate not only when it will happen, but where it will be visible. In a lunar eclipse, when the moon passes through the Earth's huge sun shadow, the event is visible on the whole side of the Earth that's in nighttime, and totality often lasts more than an hour. But in a solar eclipse, the moon's shadow falls across the Earth in a relatively narrow path, and the maximum duration of totality at any given place is only about 7½ minutes.

So you need to know the moon's orbit in great detail -- within a small fraction of a degree of arc. The early Greeks did not have this data.

We do not know the method Thales used to make his prediction. The method may have been used only once, because we have no other records of the Greeks of this era accurately predicting further eclipses. Thales is believed to have studied the Egyptians' techniques of land measurement (geo metry in Greek) later codified by Euclid. One has to wonder whether Thales made the famous eclipse prediction himself, or if he simply borrowed it from the Egyptians.

However he made the prediction, and however precise or vague it may have been, the eclipse occurred. Aylattes, the king of Lydia, was battling Cyaxares, king of the Medes, probably near the River Halys in what is now central Turkey.

The heavens darkened. Soldiers of both kings put down their weapons. The battle was over. And so was the war.

After 15 years of back-and-forth fighting between the Medes and the Lydians, the kings of Cilicia and Babylon intervened and negotiated a treaty. The River Halys, where the Battle of the Eclipse was fought, became the border between the Lydians and the Medes.

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CfA Press Release

Solar Eruption Seen in Unprecedented Detail
Cambridge, MA - On April 9, the Sun erupted and blasted a bubble of hot, ionized gas into the solar system. The eruption was observed in unprecedented detail by a fleet of spacecraft, revealing new features that are predicted by computer models but difficult to see in practice.

The observations are being discussed today in a press briefing at the American Geophysical Union Joint Assembly in Fort Lauderdale, Fla.

Such eruptions, called coronal mass ejections or CMEs, happen periodically and pose a potential threat to astronauts or satellites if aimed at Earth. Astronomers study these explosions in hope of being able to predict them and provide “space weather” forecasts.

The April 9 CME occurred on the edge or limb of the Sun as viewed from Earth. As a result, the X-ray brightening (solar flare) usually associated with a CME was hidden from view, allowing sun-watching spacecraft to take longer exposures and uncover fainter structures than usual.

“Observations like this are very rare,” said Smithsonian astronomer Ed DeLuca, (Harvard-Smithsonian Center for Astrophysics) who is presenting the findings at today’s press briefing.

Using the Smithsonian-developed X-ray Telescope (XRT) aboard the Hinode sun-watching satellite, astronomers saw a spiral (helical) magnetic structure unwind as it left the Sun during the CME. Such unwinding can release energy as the magnetic field goes from a more twisted to a less twisted configuration, thereby helping to power the eruption.

Hours later, XRT revealed an inflow of material toward a feature that appears as a bright line—actually an object known as a current sheet seen edge-on. A current sheet is a thin, electrified sheet of gas where oppositely directed magnetic field lines annihilate one another in a process known as magnetic reconnection. The extended observations from XRT show that magnetic fields flow in toward the current sheet for many hours after the eruption, progressing first toward the sheet and then down to the sun’s surface.

Computer models of CMEs predict such movements of magnetic field lines, but observing them has proven difficult. The unique positioning of this CME on the sun’s limb allowed astronomers to measure those motions.

They also determined that the temperature of the current sheet is between 5 and 18 million degrees Fahrenheit, which matches previous measurements higher up in the corona by the Ultraviolet Coronagraph Spectrometer on the SOHO spacecraft.

A workshop is planned to study in detail the results from Hinode XRT, and other observations of this event by TRACE, STEREO, RHESSI, SOHO, and Hinode’s other instruments. Together, those observations will provide a more complete picture of the source and evolution of CMEs.

Hinode is a Japanese mission developed and launched by ISAS/JAXA, with NAOJ as domestic partner and NASA and STFC (UK) as international partners. It is operated by these agencies in cooperation with ESA and the NSC (Norway).

Headquartered in Cambridge, Mass., the Harvard-Smithsonian Center for Astrophysics (CfA) is a joint collaboration between the Smithsonian Astrophysical Observatory and the Harvard College Observatory. CfA scientists, organized into six research divisions, study the origin, evolution and ultimate fate of the universe.

For more information, contact:

David A. Aguilar
Director of Public Affairs
Harvard-Smithsonian Center for Astrophysics

Christine Pulliam
Public Affairs Specialist
Harvard-Smithsonian Center for Astrophysics

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Astronauts To Fix Space Station Toilet

Plumbing Added To Discovery Mission

How do you call a plumber in space?Space shuttle Discovery will be loaded with spare parts to fix the main toilet in the Russian segment of the International Space Station; the vacuum-powered urine-collection device failed after repeated attempts to fix it last week.The three crew members on the station, a U.S. astronaut and two cosmonauts, are using the toilet in the Soyuz module. The situation could become problematic when Discovery arrives next week, and 10 people are required to share the toilet on the tiny Soyuz, which is a Russian capsule also designated to be used at an emergency escape lifeboat. The shuttle's toilet, however, could provide some relief until the ISS toilet is repaired, Local 6 News partner Florida Today reported.
Conditions are not unsanitary, said a NASA spokesman.Though Discovery will carry up replacement parts on Saturday, NASA is not yet sure which parts will be needed for replacement.With the successful arrival on Mars of the Phoenix spacecraft, NASA is turning its attention to Saturday's launch of Discovery on a mission to deliver a massive Japanese laboratory to the International Space Station.Technicians returned to work on Tuesday at launch pad 39A after most work crews had the Memorial Day weekend off. Discovery's astronaut crew arrives at Kennedy Space Center Wednesday about 11:30 a.m. The coundown begins at 3 p.m. Wednesday.Discovery will blast off at 5:02 p.m. on a trip to deliver the 37-foot Kibo laboratory to the International Space Station. Three spacewalks will be performed during the 14-day mission.Watch Local 6 News for more on this story.

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How to Win the Google Lunar X Prize and Beat NASA to the Moon

DIY space enthusiasts want to go bang, zoom, straight to the moon and win $20 million. The competition is open to all, but to take your best shot at the pot, you'll need a good game plan. We can help.
PM’s vision of a lunar lander on arrival. (Illustration by Jeremy Cook)

The year is 2012. A quarter-million miles from Earth, a small spacecraft is nearing the surface of the moon. When the unmanned craft touches down in a cloud of rocket-blown dust, it becomes the first man-made object to arrive intact on the lunar surface in 32 years.
But the logo on the side of the spacecraft doesn't belong to NASA or any other government space agency. Instead, the images beamed back to Earth by the small rover that emerges from the spacecraft reveal a familiar multicolored corporate logo: Google's. Not a single dollar of public money has been expended, or a scrap of governmental red tape encountered, during the mission.

That's the scenario envisioned by the creators of the Google Lunar X Prize, a $20 million reward for the first privately funded group to land a rover on the moon by Dec. 31, 2012. To win the prize, the rover must do more than arrive in one piece. It must ­travel at least 500 meters, or about a third of a mile, and send a "mooncast" of high-definition video, photos and text to Earth.

The point of the contest is to encourage entrepreneurs and inventors to participate. So, in the spirit of PM's long heritage of do-it-yourself projects, we offer aspiring X Prizers this guide to landing your own rover on the moon­. Don't let the tight deadline deter you from trying: If nobody wins by 2012, $15 million will remain on the table for late arrivals through at least 2014.

The X Prize Foundation models its efforts after contests that spurred technological progress and public enthusiasm during the golden age of aviation. Charles Lindbergh's 1927 flight from New York to Paris was undertaken in pursuit of the $25,000 Orteig Prize, donated by a hotel magnate in 1919. In 1996, the X Prize Foundation offered $10 million to anyone who could build a reusable spacecraft. The contest inspired aerospace maverick Burt Rutan and Microsoft billionaire Paul Allen to create SpaceShipOne, which flew private astronauts to suborbital altitudes twice within two weeks in 2004.

This latest, lunar addition to the X Prize franchise is meant to focus participants' time and money on affordable innovations. At this writing, 10 teams have registered to compete for the jackpot. "It used to take a nation to land on the moon," says Peter Diamandis, CEO of the X Prize Foundation. "We're throwing down the gauntlet to challenge pri-vate groups to do it a hundred times cheaper."

The Checkbook

Even with the most frugal project managers, winning will likely cost your team more than the prize is worth. Preliminary budget estimates made by X Prize teams range from $20 to $100 million. With billionaire benefactors like Allen in short supply, you'll have to devise creative ways to make up the difference—corporate sponsorships, perhaps, or even fees to haul precious, though creepy, cargo. "One kilogram of cremated remains soft-landed near the Apollo 11 site could be worth $5 million," says Red Whittaker, head of the Astrobotic team, a serious contender with backing from Raytheon and Carnegie Mellon University. Odyssey Moon, which developed a for-profit lunar-rover-based business plan before the X Prize was announced, says it already has $40 million in payload fee commitments.

Other proposed money-raising schemes include selling TV rights, licensing toy rovers and charging earthbound drivers for the chance to steer the rover by remote control. One team plans to enable its rover to trade instant messages with thousands of earthlings.

Although you'll have to develop your own rover, almost everything else you need—rocket motors, telemetry packages, attitude thrusters, launch vehicles—can be plucked out of the parts bins of space companies in the U.S. and abroad. "This isn't just a race to the moon, it's a race to Russia to see what kind of stuff they've got for sale," says Odyssey Moon CEO Bob Richards, whose space sensor company developed the first commercial laser radar scanner flown into space.

Having a staff of veterans on your team is a big advantage: One of the three partners in Astrobotic is Raytheon Missile Systems, which will bring in technicians with experience from prior NASA lunar programs.

Our concept for what an X Prize–winning lunar rover could look like mixes and matches the best ideas from current plans. (Render by Jeremy Cook)

The Broadcast Package

Your rover's cameras, transmitters and power supply are the design linchpins for the entire mission. The mass and volume of this core payload dictate the design of your rover, which in turn influences the lander and, ultimately, the choice of launch vehicle.

Keeping in mind that the going rate for putting commercial payloads into orbit is $5000 per pound, you should aim for a maximum target of 11 pounds for the package.

There's no need to reinvent the camera. A couple of RocketCams from Ecliptic Enterprises should weigh a total of about 3 pounds and cost in the low six figures, including a controller and cables. For a first-class upgrade—after all, $20 million is riding on the camera's performance—con­sider a $5 million video unit from Malin Space Science Systems, derived from those in development for NASA's planned Mars Science Laboratory.

Broadcasting your 1 GB data set to Earth will be a bigger challenge. "Nothing off the shelf can do this," says Rex Ridenoure, a former NASA deep-space mission engineer and co-founder of the space firm Ecliptic Enterprises.

In designing a broadcast transmitter, you'll have to balance power requirements, aiming capabilities, beam widths and data transmission rates in order to broadcast a signal. The broadcast needs 30 to 40 watts of power, presumably supplied by solar cells on your lander or rover.

The faint signal of your lunar broadcast will need to be downloaded when it reaches Earth. You should first con­sider a recent offer made to the X Prize Foundation by the Search for Extraterrestrial Intelligence Institute to use its recently opened Allen Telescope Array (ATA), which scans the universe for radio signals from intelligent extra­terrestrials. Last October the first 42 of a planned 350 dishes became operational.

But ATA only receives signals. To send commands to the rover, you can use Universal Space Network's worldwide array of radio transmitter receivers. The company will rent the dishes and process all communications during the trip for a couple of hundred thousand bucks.

The Rover

Your design goal is deceptively simple: Build the smallest, lightest rover that will carry your broadcast package across the required 1640 ft. of lunar terrain. You'll also have to decide whether to use a rover that separates from the lander or combine the two vehicles into one unit.

Astrobotic's Whittaker, a long-time Car­negie Mellon rover guru who recently won the Pentagon's $2 million DARPA Urban Challenge, envisions a 130-pound, four-wheel rover about waist high. One side will be draped with solar panels. As the rover zigzags across the moon, the panels will continually face the sun. Astrobotic's ambitious plan calls for a landing near the Apollo 11 site in July '09, the 40th anni­versary of Neil Armstrong's arrival, and perhaps a 15-mile journey to Surveyor 5, a 1967 NASA lander.

Taking the minimalist approach to an extreme, one team claims its rover might be the size of a cellphone. Another, headed by geo­stationary-satellite pioneer Harold Rosen, plans to use a "hopper" that would fire its hydrazine rockets for a few seconds in the weak lunar gravity and, in a series of jumps, travel the prescribed distance. An Italian team suggests using several small robots on mechanical legs. "Anything goes," Diamandis says. "We want to inspire totally new thinking."
A. Made-to-Order Rovers: Unless your team is allied with a company or university that has spare rovers, like Carnegie Mellon, prepare to custom-build your own rig. B. Rented Rockets: Lockheed’s Athena II is the only rocket on the market that has delivered cargo to the moon. It costs $25 million—more than the prize is worth. C. Donated Data Link: Owners of the Allen Telescope Array, which is used to detect alien radio signals, are offering several days of free reception for X Prizer “mooncasts.” D. Landers Are Tricky: In 2007, Armadillo Aerospace engineers competed in a privately funded lunar lander challenge. Despite several successful test flights, their liquid-oxygen- and ethanol-fueled craft could not win the prize. No other team fielded a flight-ready contender.

The Lander

Your spacecraft will likely be traveling at about 5000 mph during its approach to the moon, and, without an atmos­phere, a parachute is useless for braking and producing a gentle touchdown. "This isn't a competition about rovers," says Bob Richards of Odyssey Moon. "It's really a competition about landers. The winner is the team that gets this part right."

All landers will require retrorockets to slow down during the descent. Fortunately, ATK Thiokol Propulsion offers a variety of tested solid-fuel motors for this task. "There's almost no margin for error with the landing," Ridenoure says. "It'll be a nail-biter."

You may prefer to have an autonomous lander because the 3-second delay in radio transmissions from the moon makes remote controls sluggish. If you're going for the $1 million bonus prize for a closeup look at a man-made artifact on the surface, you'll need a pinpoint guidance system. Good luck trying to match Astrobotic, which plans to guide its craft with software developed by Raytheon to steer Tomahawk cruise missiles.

Finding lunar landing experience in the private sector is tricky. For example, a previous earthbound X Prize, the $2 million Lunar Lander Challenge, still awaits a winner after two years. The goal of that contest is to build something that can take off vertically from the New Mexico desert, hover at 150 ft. and then land at a designated spot 328 ft. away. Only one team, computer gaming guru John Carmack's Armadillo Aerospace, has managed even to fdevelop a contest-ready lander—but it has yet to beat the challenge.

SpaceDev, which helped develop the hybrid rocket motor for SpaceShipOne, recently flew a prototype lunar lander during a brief cable-guided test for a private international astronomical group that wants to establish a lunar telescope. Company officials say the lander can carry an X Prize rover and that at least one team has shown interest.

The Launch Vehicle

Prepare to enter a murky, secretive world where commercial launch providers' brochure claims may be suspect and prices are "very negotiable," according to space consultant Charles Bradley. Depending on your budget and the mass of your rover/lander package, you have a number of commercial launch options from large aerospace corporations, small startups and international players.

+ Click to enlarge
Click to enlarge
Planning Your Lunar Road Trip: There is no single ideal route to the moon. In picking the best travel strategy, you have to balance time against the need to conserve weight and fuel.
If you are diplomatically savvy and also lucky, there are several budget-friendly options, like thumbing a ride on an already planned geostationary-satellite launch. Once in orbit around the Earth, you'll separate from the satellite and do your own final burn to the moon's orbit. Better yet, we hear that the Russian firm Lavochkin has 440 pounds of spare payload space available all the way to lunar orbit on the announced Luna-Glob mission, set for 2012.

These options should be considered long shots: Experimental hitchhikers are not usually welcomed on presold commercial launches. That leaves more expensive alternatives. Elon Musk, the PayPal mogul and founder of SpaceX, has spent more than $100 million to develop the world's lowest-cost space launcher. Musk, who sits on the X Prize board, has promised competing lunar teams a 10 percent discount off the bargain $8.5 million list price for a ride on the still-in-development Falcon 1.

Although SpaceX has been designated the contest's "preferred launch provider," their base-model Falcon 1 has yet to reach low Earth orbit, much less blast off a moonshot. Two test firings have both fallen short; a long-delayed third attempt to reach Earth orbit is set for this summer. Some team leaders have expressed skepticism that the Falcon 1 will be able to handle the weight of their rovers, landers and rocket­braking stages. Going bigger means a costlier investment: SpaceX's much larger Falcon 9 is scheduled to fly in 2009, but at a prediscount price of $47 million. The only proven commercially available moon rocket is Lockheed Martin's Athena II, which in 1998 boosted NASA's Lunar Prospector into orbit around the moon. The company claims the rocket can send about 800 pounds to the moon. The last Athena II launch was nine years ago, and Lockheed Martin is mum about building more. Estimated price: $25 million.

Demilitarized nuclear missiles are another good option. Orbital Sciences' Minotaur V is a proposed modification of the surplus Peacekeeper ICBM. The missile, not yet cleared for commercial use, could loft nearly 1000 pounds of payload out of Earth's orbit at an estimated price of $30 million. In a similar swords-to-plowshares conversion, the Kosmotras Dnepr is based on a former Russian ICBM and can now launch 1600 pounds toward the moon, for the bargain price of $15 to $20 million.

Realistically, the odds seem to be against a prize-winning lunar mission by 2012. But take heart: Lindbergh and Rutan beat long odds. If you manage to snag a friendly billionaire and follow our how-to guide, there's no reason you won't be ready to join the pantheon of aerospace prizewinners.

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Post-traumatic stress soars in U.S. troops

By David Morgan

WASHINGTON (Reuters) - Newly diagnosed cases of post-traumatic stress disorder among U.S. troops sent to Iraq and Afghanistan surged 46.4 percent in 2007, bringing the five-year total to nearly 40,000, according to U.S. military data released on Tuesday.

The statistics, released by the Army, showed the number of new PTSD cases formally diagnosed at U.S. military facilities climbed to 13,981 last year from 9,549 in 2006.

The numbers rose as President George W. Bush poured extra forces into Iraq to try to quell sectarian violence and extended Army tours from 12 to 15 months. The United States has also sent more forces to Afghanistan.

The figures, encompassing all four branches of the U.S. armed services, showed that the Army alone had 10,049 new PTSD cases last year.

This brings to 39,366 the number of PTSD cases diagnosed at military facilities between January 1, 2003, and December 31, 2007, among troops deployed to Iraq or Afghanistan.

The totals include 28,365 cases for the Army, 5,641 for the Marines, 2,884 for the Navy and 2,476 for the Air Force.

Army officials said the larger number of PTSD diagnoses in recent years partly reflects greater awareness and tracking of the disorder by the U.S. military.


"But we're also exposing more people to combat," Lt. Gen. Eric Schoomaker, the Army surgeon general, told reporters.

Experts also say PTSD symptoms increase as soldiers return to combat for multiple tours of duty.

PTSD is a health condition that can result from wartime trauma such as being physically wounded or seeing others hurt or killed.

Symptoms range from irritability and outbursts of anger to sleep difficulties, trouble concentrating, extreme vigilance and an exaggerated startle response. People with the condition can persistently relive the traumatic events that initially induced horror or helplessness.

The Pentagon has come under mounting political pressure in recent years to enhance treatment for PTSD amid criticism that initial programs were inadequate.

Earlier this month, Defense Secretary Robert Gates announced a change in the U.S. government clearance process that allows PTSD sufferers to seek help for combat-related mental health problems without risking their military careers.

Army officials on Tuesday emphasized that the data do not reflect the actual number of troops and war veterans who suffer from PTSD, many of whom do not seek treatment or have been diagnosed at civilian facilities where records are confidential.

A recent study by the RAND Corp. estimated about 300,000 troops, or 18.5 percent, of the more than 1.5 million troops sent to Iraq and Afghanistan exhibit symptoms of either PTSD or depression.

The fresh statistics add detail about the scale of human suffering from two wars that have killed 4,579 U.S. troops and inflicted physical wounds on 32,076 more.

There currently are 155,000 U.S. troops in Iraq and 33,000 in Afghanistan.

(Editing by Will Dunham and Bill Trott)

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Scientists create new nanotube structures

Thanks to the rising trend toward miniaturization, carbon nanotubes – which are about 100,000 times thinner than a human hair and possess several unique and very useful properties – have become the choice candidates for use as building blocks in nanosized electronic and mechanical devices. But it is precisely their infinitesimal dimensions, as well as their tendency to clump together, that make it difficult for scientists to manipulate nanotubes.

Dr. Ernesto Joselevich, together with Ph.D. student Ariel Ismach and former M.Sc. student Noam Geblinger of the Weizmann Institute’s Materials and Interfaces Department, are developing techniques to coax carbon nanotubes to self-assemble into ordered structures – essentially making the nanotubes do the hard work for them.

An animated movie explaining nanotube serpentine formation:

Ironically, the universal principle of 'order through chaos,' has allowed the team’s most recent research to give rise to nanotubes that are strikingly more ordered and complex than any ever observed before. These intriguing new nanotube structures, which the scientists have dubbed 'serpentines' due to their self-assembly into snake-like or looped configurations, have recently been reported in the cover article of the journal Nature Nanotechnology.

'It may seem paradoxical – trying to create order through chaos – but in fact, this a common phenomenon on the macroscale. Systems affected by forces that fluctuate from one extreme to another tend to self-organize into much more complexly ordered structures than those in which the external forces are ‘calm.’ We applied this principle at the nanoscale to see if it would have the same effect, and indeed, it did,' says Joselevich.

Serpentines are a common geometry in many functional macroscale systems: antennas, radiators and cooling elements. Analogously, nanotube serpentines could find a wide range of nano-device applications, such as cooling elements for electronic circuits and opto-electronic devices, as well as in power-generating, single-molecule dynamos. 'But the feature I find most intriguing about these serpentines,' says Joselevich, 'is their beauty.'

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Religion is a product of evolution, software suggests

God may work in mysterious ways, but a simple computer program may explain how religion evolved

By distilling religious belief into a genetic predisposition to pass along unverifiable information, the program predicts that religion will flourish. However, religion only takes hold if non-believers help believers out – perhaps because they are impressed by their devotion.

"If a person is willing to sacrifice for an abstract god then people feel like they are willing to sacrifice for the community," says James Dow, an evolutionary anthropologist at Oakland University in Rochester, Michigan, US, who wrote the program – called Evogod (download the code here).

Dow is by no means the first scientist to take a stab at explaining how religion emerged. Theories on the evolution of religion tend toward two camps. One argues that religion is a mental artefact, co-opted from brain functions that evolved for other tasks.

Aiding the people

Another contends that religion benefited our ancestors. Rather than being a by-product of other brain functions, it is an adaptation in its own right. In this explanation, natural selection slowly purged human populations of the non-religious.

"Sometime between 100,000 years ago to the point where writing was invented, maybe about 7000 BC, we begin to have records of people's supernatural beliefs," Dow says.

To determine if it was possible for religion to emerge as an adaptation, Dow wrote a simple computer program that focuses on the evolutionary benefits people receive from their interactions with one another.

"What people are adapting to is other people," he says.

Religious attraction

To simplify matters, Dow picked a defining trait of religion: the desire to proclaim religious information to others, such as a belief in the afterlife. He assumed that this trait was genetic.

The model assumes, in other words, that a small number of people have a genetic predisposition to communicate unverifiable information to others. They passed on that trait to their children, but they also interacted with people who didn't spread unreal information.

The model looks at the reproductive success of the two sorts of people – those who pass on real information, and those who pass on unreal information.

Under most scenarios, "believers in the unreal" went extinct. But when Dow included the assumption that non-believers would be attracted to religious people because of some clear, but arbitrary, signal, religion flourished.

"Somehow the communicators of unreal information are attracting others to communicate real information to them," Dow says, speculating that perhaps the non-believers are touched by the faith of the religious.

Ancient needs

Richard Sosis, an evolutionary anthropologist at the University of Connecticut in Storrs, US, says the model adds a new dimension to the debate over how religion could have evolved, which has previously relied on verbal arguments and speculation. But "these are baby steps", he cautions.

Sosis previously found that in some populations – kibbutzim in Israel, for instance – more religious people receive more assistance from others than the less faithful. But he notes that the forces that maintain religion in modern humans could be very different from those that promoted its emergence, thousands of years ago.

Palaeolithic humans were probably far more reliant than modern humans on the community they were born into, Sosis says. "[Now] you can be a Lutheran one week and decide the following week you are going to become a Buddhist."

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Dinosaur tracks discovered in Arabian peninsula

The tracks of a herd of dinosaurs have been discovered on mud flats in Yemen - the first discovery of dinosaur footprints on the Arabian peninsula.

They were made by 11 long-necked sauropods, the largest land animal in Earth's history, which walked on four stout legs and ate plants.

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A tourist touches a footprint of a sauropod, 31 miles north of the Yemeni capital Sanaar. Below, an artists's impression of the largest land animal in Earth's history

"The nice thing is we finally filled in a bit of a blank spot in the dinosaur map," said Anne Schulp, a palaeontologist at the University of Maastricht in the Netherlands, who worked on the study.

"Until 10 years not even bones were known from the Arabian peninsula and at last we have some dinosaur tracks."

The footprints dating from about 150 million years ago showed the sauropods travelling at the same speed along a river, likely in search of food, Schulp said in a telephone interview.

The creatures roamed the Earth from about 228 million years ago to 65 million years ago, the middle of the age of dinosaurs.

The well-preserved tracks, found about 50 miles north of Yemen's capital Sanaa, ranged from 43 centimetres to 70 centimetres and suggested strides of about 2.5 meters, Schulp added.

dinosaur footprint

Discovery: The sauropod footprints are the first dinosaur tracks found on the Arabian peninsula

Paleontologists have so far unearthed only a few dinosaur fossils from the Arabian peninsula and possible fragments of a long-necked dinosaur from Yemen.

"The nice thing about tracks is you can tell what these guys were doing," Schulp said. "You can put some life into the fossils."

The researchers had first found evidence of a large ornithopod, a two-legged, plant-eating dinosaur, and then discovered the sauropods' tracks close by.

Schulp and his colleague Mohammed Al-Wosabi of the University of Yemen measured the shape and angle of the different digits in one of the prints to identify the bipedal dinosaur as an ornithopod.

They then used the size, shape and spacing of the other prints to determine body size, travel speed and other distinguishing features of the sauropod herd, they reported in the journal PLoS ONE on Wednesday.

"We really want to learn when did which dinosaurs live, where, and why was that," Schulp said. "How did the distribution change over time, why did one replace another and move from one place to another?"

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New mosquito sprays better than DEET

DEET is the most widely used mosquito repellent for the last five decades. So isn’t it time scientists discovered a better one? This ScienCentral News video explains how new research could bring us a better bug spray.

[If you cannot see the youtube video below, you can click here for a high quality mp4 video.]

Interviewee: Ulrich Bernier
USDA/University of Florida-Gainesville
Length: 1 min 28 sec
Produced by Joyce Gramza
Edited by James Eagan
Copyright © ScienCentral, Inc.

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Why Don't Monkeys Infected With HIV-like Viruses Get AIDS?

Many strains of monkey become naturally infected with viruses that are related to HIV. These viruses are known collectively as SIV and naturally infected monkeys do not develop AIDS. It is hoped that understanding why monkeys naturally infected with SIV do not develop AIDS might teach researchers important lessons about the mechanisms underlying the development of AIDS in humans infected with HIV and identify ways to prevent this happening.

New insight into the mechanisms that control the number of virus particles in the blood of sooty mangabeys naturally infected with SIVsmm, the strain of SIV that naturally infects sooty mangabeys, has now been provided by a team of researchers from the University of Pennsylvania, Philadelphia, and Emory University, Atlanta.

HIV and SIV infect immune cells known as CD4+ T cells. So, the authors set out to determine how CD4+ T cells affected the number of virus particles in the blood of sooty mangabeys naturally infected with SIVsmm -- did they provide immune control of the number of virus particles or did they simply provide a place to live a replicate.

The number of SIVsmm particles in the blood of naturally infected sooty mangabeys decreased when the monkeys were depleted of CD4+ T cells and then increased again as the number of proliferating CD4+ T cells rebounded.

So, it was concluded that availability of proliferating CD4+ T cells is a key determinant of how many SIVsmm particles can be detected in the blood of naturally infected sooty mangabeys, rather than CD4+ T cells providing immune control of the virus.

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The Next 5 Extreme Research Machines You Need to Know

Forget the Large Hadron Collider: Whether they’re tracking Martian robots, simulating hurricanes or fending off the supernova apocalypse, these supersize science projects don’t just look cool—they’re hunting some of the world’s biggest unsolved mysteries.
Some 3000 ft. below the surface of Japan, the Super-Kamiokande detector is on the lookout for faster-than-light Cherenkov particles that might signal a supernova.

The fact that you
may have heard of the Large Hadron Collider (LHC) is a landmark achievement in hype. This superstar among particle accelerators, buried hundreds of feet below Switzerland and France, is the rare scientific undertaking that arrives in a frenzy of publicity. This summer, protons will begin colliding in the LHC’s 17-mi.-long circular tunnel. If everything goes according to plan, the accelerator could supply some of the biggest, most elusive pieces of the cosmic jigsaw puzzle, from details on the elusive mass of dark matter that physicists have long sought, to the framework for a Grand Unified Theory. This would explain the relationship between electromagnetism and strong and weak nuclear forces, three of the fundamental forces of nature. (The collider could also create an earth-swallowing black hole, solving both the world credit crunch and the glut of Hannah Montana-branded goods, but that possibility has been overstated, according to scientists.)

The LHC is also getting attention because of its looks. With miles of cables and tunnels and multiple hulking particle detectors, almost any photograph of any part of this accelerator is like a glamour shot of a supervillain’s doomsday weapon. But there’s room for more than one groundbreaking megamachine in today’s scientific pantheon. Around the globe, natural mysteries are under assault from all kinds of colossal devises, from a ship that probes the magma miles below the planet’s surface to a neutrino detector designed to detect the first signs of a galactic supernova. These research machines aren’t celebrities yet, but they deserve to be.

1. Super-Kamiokande

It isn’t the biggest neutrino observatory in the world, or the most sensitive. But if a supernova ever goes off in the Milky Way, physicists will be grateful for the Super-Kamiokande (Super-K, pictured above). Buried more than 3000 ft. underground in central Japan, and filled with 50,000 gal. of purified water, the Super-K is designed to detect various types, or “flavors,” of neutrinos. Specifically, it analyzes Cherenkov light, the visible blue radiation that’s generated when a particle exceeds the speed of light (didn’t know that could happen, did you?). Likened to an optical sonic boom, Cherenkov light is a familiar—if unnerving—sight in nuclear reactors. It occurs when charged particles passing through some sort of medium, such as water, in which the light is actually slowed down (okay, so we’re stretching the truth on the speed-of-light thing).

The Super-K, which is composed of a 135-ft.-tall stainless steel cylinder and a smaller, interior structure, employs thousands of light sensors to detect the neutrinos at work within the Cherenkov radiation. Researchers have used the observatory to confirm that the sun produces neutrinos. Also, the Super-K was among the first detectors used to dispute the theory that neutrinos have a non-zero mass. But the observatory’s most accessible function, and potentially its most important, is its role in the Supernova Early Warning System (SNEWS). The Milky Way is overdue for a supernova—the last one happened 400 years ago—which could be a research goldmine for physicists. That’s assuming they know it’s coming, and have the proper instruments ready to collect the incoming data. Since the more visible—and violent—effects of a supernova are preceded by a burst of neutrinos, the Super-K is on a constant lookout for a sudden, suspicious influx of the faster-than-light particles. By the way, a supernova could eliminate all life on Earth by bathing us in lethal gamma rays. Scientists say the next supernova probably will be too far off to cause us harm. Otherwise, though, the Super-K will provide a crucial few hours in which to hop into our transgalactic escape pods. Or, more likely, to bend over and kiss our charged particles goodbye.

2. 45 Tesla Hybrid

As world records go, the one held by the 45-T hybrid magnet at the National High Magnetic Field Laboratory at Florida State is a little confusing. It’s the largest, most powerful magnet in the world ... that generates a sustained field. So while there are stronger pulsed magnets, this 22-ft.-tall, 35-ton model is the most consistently powerful, capable of fields as strong as 45 tesla. That means it’s around one million times stronger than the planet’s magnetic field, and as much as 20 times stronger than the magnet in an MRI machine.

To achieve fields that powerful, this hybrid magnet—it’s composed of a 11.5 tesla superconducting magnet and a 33.5 tesla resistive magnet—is surrounded by pipes filled with purified water and liquid helium, which keep the machine running at 1.8 Kelvin, or –456 F. None of which explains why this high-powered magnet is in such high demand among researchers. Molecules behave differently in strong magnetic fields, becoming easier to analyze (like a molecular, zoomed-in version of an MRI scan) or sometimes even taking on different basic properties. The holy grail of high-field magnetic research is room-temperature superconductivity, which would provide all the benefits of superconductive materials (essentially zero resistance to electric currents) without the need for expensive liquid helium or nitrogen systems. There’s no guarantee that the 45-T will chase down that particular grail, but it remains one of the most powerful—and useful—magnets in the world.

(Photograph by Kristen Bartlett Grace/University of Florida)

3. Hurricane Simulator

The cause is noble, but there’s something deliciously evil about the University of Florida’s Hurricane Simulator, with its eight 5-ft.-tall fans capable of generating 130 mph winds—equivalent to a Category 3 hurricane—and high-pressure water jets that can simulate rainfall as heavy as 35 in. per hour.

A 5000-gal. water tank cools the machine’s four marine diesel engines, which add up to 2800 hp. The fans actually generate 100-mph winds, which pass through a duct that constricts the flow of air, and boosts its speed. The Simulator has been used to test the effects of extreme rain and hurricane-force gusts on structures, and was joined last week by a device that launches high-speed shingles.

4. Green Bank Telescope

Officially, it’s the world’s largest fully steerable radio telescope, standing 485 ft. high, and weighing 17 million pounds. More importantly, the Green Bank Telescope (GBT) is one of the largest moving objects on Earth. Its dish measures 100 x 110 meters, and the unique, asymmetric shape prevents the receiver’s support structure from obscuring the mirror, itself composed of more than 2000 aluminum surface panels.

By adjusting the dish on its massive wheel-and-track assembly, as well as tweaking the shape of the mirror with actuators attached to each panel, scientists can use GBT to acquire a full view of the sky above 5 degrees elevation. The instrument also has an extremely high sensitivity to incoming radio signals. The GBT, which is named for Green Bank, West Virginia, a federally mandated radio-free zone, has made strides in the study of distant pulsars. Its latest mission? Tracking NASA’s Phoenix Lander, which just landed on Mars.

5. Drilling Vessel Chikyu

On track to break not one, but two world records, the international Drilling Vessel Chikyu is the largest research drilling vessel on the planet, and it’s designed to bore deeper into the Earth’s mantle than anything in history. Technically speaking, a Russian program has created a hole with greater depth (12 km), but the Chikyu’s 400-ft.-tall tower will drill 7 km into an earthquake-prone subduction zone off the coast of Japan, where the Earth’s crust is comparatively thin. The vessel was built specifically for a single multiyear research expedition, and scientists hope to learn more about the planet’s mantle, and why normally smooth-moving tectonic plates can suddenly become locked, causing earthquakes and tsunamis.

The Chikyu is the first research vessel to use the oil industry’s riser technology, where the drill pipe is surrounded by a fluid-filled casing, to stabilize the pressure within the hole. The vessel is also equipped with computer-controlled, 360-degree thrusters, which respond to GPS data to keep the Chikyu stable during drilling operations—if the ship drifts more than a few yards, the pipe could break. One such accident has already briefly set the expedition back, but the vessel is on schedule to finish its experiments by 2012.

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Top 10 Sci Can't Explain

It's time to cut to the chase with a look at the top ten things that science just can't explain - yet. No we're not talking minor mysteries like how Keith Richards is still walking, these are the biggies. Logan Wright ponders the questions that have still got us baffled.

(click on the links for the inside story)

10. The WOW! signal
Wow, a secret message from outer space! Twenty years on and still no nearer an answer.
9. Pioneer's Funky Voyage
The creators of these deviant probes are ripping their hair out trying to understand what went wrong.
8. Female Orgasms
After a whole lot of thinking, biology’s best minds are still confused.
7. Dark Energy
The universe is a dark, dark place, which makes it ruddy difficult to study.
6. The Speed of Light
Faster than a speeding photon: is it possible? Einstein stays no, but does everyone else?
5. The Placebo Effect
Take this pill and you’ll be cured, just as long as you believe me.
4. Cold Fusion
Can atoms get together and let off some steam without the sauna?
3. Yawning
Open your mouth and notice the shockingly fascinating mystery of the yawn.
2. Dark Matter
Just because you can’t see the WIMPs and MACHOs doesn’t mean they aren’t there.
1. What Came Before, What Will Come After
Wouldn't it be really boring if it was just blackness. However, anyone's guess is as good as ours.
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Thermal management growing to $11.1B worldwide

According to a new technical market-research report entitled The Market for Thermal Management Technologies, BCC Research states the global market for thermal management was worth $6.1 billion last year. The researcher expects that market to increase to $6.8 billion this year and $11.1 billion by the end of 2013, a compound annual growth rate of 10.3 percent.

The development of the thermal management industry is one of the most interesting aspects of the innovation in the high-technology industry, BCC says. As pressure to achieve higher levels of device integration while reducing cost, size, and complexity continues, the issue of managing heat and power dissipation has become increasingly significant.

Thermal management hardware, including fans and blowers and heat sinks, accounts for more than 80 percent of the total thermal management market. The other main thermal management product segments-software, interface materials, and substrates-each account for about 4 to 6 percent of the market.

The largest end markets for thermal management technologies last year were the computer industry, with 57 percent of total revenues; telecommunications, accounting for 16 percent; and industrial/military electronics, claiming 9 percent. By 2013, medical and office electronics should have moved into a tie for second place with telecommunications, each with 12 percent market share, followed by consumer electronics at 8 percent.

From a geographical standpoint, the Americas (United States and Latin America) will maintain its number-one position throughout the period under review, with a market share of just under 40 percent. The Asia-Pacific region will follow with 23 to 24 percent; with the exception of Japan, the Asia-Pacific countries are not only the second-largest market in absolute terms, but also have the highest projected growth rate.

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Is there an opposite to absolute zero?

Seems like an innocent enough question, right? Absolute zero is 0 on the Kelvin scale, or about minus 460 F. You can't get colder than that; it would be like trying to go south from the South Pole. Is there a corresponding maximum possible temperature?

Well, the answer, depending on which theoretical physicist you ask, is yes, no, or maybe. Huh? you ask. Yeah, that's how I felt. And the question doesn't just mess with the minds of physics dummies like me. Several physicists begged off of trying to answer it, referring me to colleagues. Even ones who did talk about it said things like "It's a little bit out of my comfort zone" and "I think I'd like to ruminate over it." After I posed it to one cosmologist, there was dead silence on the other end of the line for long enough that I wondered if we had a dropped call.

I had touched a nerve, because, unbeknownst to me, the highest-temperature question gets to the heart of current inquiries and proposed theories in cosmology and theoretical physics. Indeed, scientists who work in these fields are zealously trying to answer that question. Why? Because, in some sense, nothing less than the future course of physics rests on the answer.


For many of us, the hottest thing we could think of might be the core of the sun. But broiling as it is at roughly 107 degrees, it's a full 25 orders of magnitude colder than the current highest temperature that physicists propose.

Contender #1—1032 K

Certain cosmological models, including the one that has held sway for decades, the Standard Model, posit a theoretical highest temperature. It's called the Planck temperature, after the German physicist Max Planck, and it equals about 100 million million million million million degrees, or 1032 Kelvin. "It's ridiculous is what it is," said Columbia physicist Arlin Crotts when I asked him if he could please put that number in perspective for me. "It's a billion billion times the largest temperature that we have to think about" (in gamma-ray bursts and quasars, for instance). Oh, that helped.

Truthfully, when contemplating the Planck temperature, you can forget perspective. All the usual terms for very hot—scorching, broiling, hellish, insert your favorite here—prove ludicrously inadequate. In short, saying 1032 K is hot is like saying the universe occupies some space. (For a game attempt at perspective, see A Sense of Scale.)

Whatever the highest temperature is, it might be essentially equivalent to the coldest temperature.

In conventional physics—that is, the kind that relies on Einstein's theory of general relativity to describe the very large and quantum mechanics to describe the very small—the Planck temperature was reached 10-43 seconds after the Big Bang got under way. At that instant, known as one Planck time, the entire universe is thought to have been the Planck length, or 10-35 meters. (In physics, Max Planck is the king of the eponymous.) An awfully high temperature in an awfully small space in an awfully short time after … well, after what? That's arguably an even bigger question—how did the universe begin?—and we won't go there.


Quasars, such as this one appearing quadrupled through the "gravitational lensing" effect of an intervening galaxy, are among the most energetic, hence hottest, of celestial objects. But even they pale next to the temperature right after the Big Bang.

A brick wall

The Planck temperature is the highest temperature in conventional physics because conventional physics breaks down at that temperature. Above 1032 K—that is, earlier than one Planck time—calculations show that strange things, unknown things, begin to happen to phenomena we hold near and dear, like space and time. Theory predicts that particle energies become so large that the gravitational forces between them become as strong as any other forces. That is, gravity and the other three fundamental forces of the universe—electromagnetism and the strong and weak nuclear forces—become a single unified force. Knowing how that happens, the so-called "theory of everything," is the holy grail of theoretical physics today.

"We do not know enough about the quantum nature of gravitation even to speculate intelligently about the history of the universe before this time," writes Nobel laureate Steven Weinberg about this up-against-a-brick-wall instant in his book The First Three Minutes. "Thus, whatever other veils may have been lifted, there is one veil, at a temperature of 1032 K, that still obscures our view of the earliest times." Until someone comes up with a widely accepted quantum theory of gravity, the Planck temperature, for conventional physicists like Steven Weinberg, will remain the highest temperature.

CBR visualization

Even after 14 billion years, a remnant of the Big Bang's beyond-astronomical levels of heat exists in the cosmic background radiation (CBR), which has cooled to just three degrees above absolute zero. Here, the CBR is "seen" in a NASA image.

Contender #2—1030 K

String theorists, those physicists who believe the universe at its most fundamental consists not of particles but of tiny, vibrating strings, have their own take on temperature. I spoke to Robert Brandenberger, a theoretical cosmologist at McGill University in Montreal. Along with Harvard string theorist Cumrun Vafa, Brandenberger has proposed a model of the early universe that's quite different from that of traditional Big Bang models. (I should note that there are many models out there; I'm touching on only a few here.)

Called string gas cosmology, this model posits a maximum temperature called the Hagedorn temperature. (It's named after the late German physicist Rolf Hagedorn.) "This is the maximal temperature which string theory predicts," Brandenberger told me. While string theorists don't give a specific number for the Hagedorn temperature, Brandenberger has reasons to think it's about one percent of its theoretical cousin, the Planck. That makes it about 1030 K, or two orders of magnitude below the Planck.

Contender #3—1017 K

I learned of yet another highest possible temperature from Brandenberger's former graduate student, Stephon Alexander. Now an assistant professor of physics at Penn State, Alexander is one of many physicists who are eagerly awaiting the day that officials at CERN on the Swiss-French border switch on the Large Hadron Collider, the world's largest particle accelerator.

One reason why they're excited has to do temperature. As Alexander told me, "It may be that the [highest possible] temperature is—as I believe—the temperature or the energy right around the energy that the LHC will be probing." The LHC will operate at 14 trillion electron volts, or terra electron volts, designated TeV. Fourteen TeV equals 1017 K, thus 15 orders of magnitude below the Planck.

Why could the LHC help determine this? As Brandenberger explained to me, string theory predicts that space-time has more than four dimensions, either 10 or 11. "Now, the other dimensions, which are hidden to us, could either be very, very tiny—they could be strings or Planck scale—or else they could be TeV scale." And if these extra dimensions prove to be TeV scale, he says, then the topmost temperature will be TeV scale too.

Ultraviolet image of sun's corona

Could absolute cold and absolute hot—whatever it is, if it even is—be manifestations of the same physical phenomenon? Here, an ultraviolet image of the sun's corona.

I asked Alexander what it would mean for physics if the Planck temperature turned out to be TeV scale. "Oh my God, this would be one of the biggest breakthroughs of our species—you know, Einstein stuff," he said. "It'd be as big as the discovery of relativity and quantum mechanics itself." Brandenberger, for his part, thinks it's a "very, very long shot" that temperature's upper terminus is TeV scale. Regardless of who's right on this score—if, in fact, either is—it will be nail-bitingly suspenseful to see what arises from the LHC, which is slated to begin operation in 2008. Says Alexander: "I've got my stock invested."

Contender #4—0 K

As if at least three different possible opposites to absolute zero weren't pause-giving enough, what Alexander told me next really set my head spinning. Whatever the highest temperature is, he said, it might, just might be essentially equivalent to the coldest temperature. "In other words, zero temperature is the same, in a sense, as the Planck temperature."

Come again?

Alexander described two potential ways the universe began. Either it was at the Planck temperature and then inflated and cooled to create what we see today. Or it started off at zero temperature and speeded up as it expanded. "So one of two situations could have happened," he said, "and it would be interesting if, indeed, both situations are really the same underlying phenomenon."

That is, could the physics of the coldest possible temperature be equivalent to the physics of the hottest possible temperature? Considering that beyond both limits—below one and above the other—space and time start to do those strange, unknown things, Alexander believes it's "a logical conclusion, a logical possibility. Why not?"

Solar eclipse composite image

In the end, no one knows if there's a hottest-of-all temperature. But that uncertainty only fuels physicists' speculations. Above, a composite image of the sun during the total solar eclipse of June 21, 2001.

Beyond the beyond

Why not, indeed? After chatting with Alexander and others in his rarefied field, I was up for anything. How about something theoretically hotter than the Planck? Sure! I asked Jim Gates of the University of Maryland. "All we know is that above the Planck temperature, the rules change, but … we don't know what the rules change to," he said. "If someone figures out such consistent rules, then yes, it's conceivable that there will be hotter temperatures."

How about a boundlessly high temperature? Great! After all, classical general relativity calls for an infinitely high temperature at the very start of the universe, as well as in the centermost point, the singularity, of black holes.

Or, if there is a hottest temperature, whatever it is, how about something even hotter? No problem! In theory, a hotter temperature than a hottest temperature can exist—it's a negative temperature. As Charles Kittel and Herbert Kroemer write in their classic text Thermal Physics, "The temperature scale from cold to hot runs +0 K, …, +300 K, …, +∞ K, -∞ K, …, -300 K, …, -0 K."

Almost giddy now, I again turned to Arlin Crotts for help. If, theoretically speaking, you go above the Planck to an infinitely high temperature, the next step beyond infinity is minus infinity? "Well, you're not talking about thermal distribution anymore," he said, "but if you keep pushing it, you basically go through infinity over to minus infinity and then come around on the other side." Wow! "What you really should be paying attention to," he added, "is 1 over T [where T is temperature], because one over infinity and one over minus infinity are basically the same thing." Totally!

Contender #5—Who the heck knows?

As you might have guessed, by this point the physicists had lost me—if not at the very beginning. I was way out of my comfort zone.

In the end, perhaps the best answer to my question came from Lee Smolin of the Perimeter Institute for Theoretical Physics in Waterloo, Ontario. "It may be that the most you're going to be able to say is that there's a possibility that there's a highest possible temperature," he told me. "But let me mull it over…."

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Sweden turning sewage into a gasoline substitute

A FordonsGas filling station. The company operates the largest chain of biogas stations in Scandinavia.
(Nils-Olof Sjoden/FordonsGas )
[Enlarge this image]

GOTEBORG, Sweden: Taking a road trip? Remember to visit the toilet first. This city is among dozens of municipalities in Sweden with facilities that transform sewage waste into enough biogas to run thousands of cars and buses.

Cars using biogas created a stir when they began to be rolled out on a large scale at the start of the decade. The tailpipe emissions are virtually odorless, the fuel is cheaper than gasoline and diesel, and the idea of recovering energy from toilet waste appealed to green-minded Swedes.

"When you're in the bathroom in the morning and you can see something good come of that, it's easy to be taken in by the idea - it's like a utopia," said Andreas Kask, a business consultant who drives a taxi in Goteborg. "But it hasn't worked out that well in reality."

Drivers complained that there were too few filling stations and that cars only held enough biogas for two or three hours of driving. Some also said early models of biogas cars performed poorly on steep climbs, were sluggish on damp mornings and had reduced trunk room because of bulky tanks.

Critics also question the sustainability of the technology because some of the systems use pipelines that carry natural gas to reach consumers, thereby mixing the two fuels together.

Two years ago, Volvo, which is owned by Ford Motor, announced that it would stop production of biogas cars and instead focus on making environmentally friendly vehicles powered by ethanol blended with gasoline.

"We didn't sell enough cars," said Maria Bohlin, a spokeswoman for Volvo, referring to biogas models. "We might consider making biogas cars again, although we're not there at the moment."

Since Volvo's decision to stop using the biogas technology, ethanol has made deeper inroads into the Swedish market, despite criticism that it contributes to deforestation and raises food prices. Made from cereal and sugar crops, ethanol also sells for slightly less than biogas in Goteborg, although proponents of biogas say that their fuel is far more efficient per kilometer.

Goran Varmby, an official at Business Region Goteborg, a nonprofit company that promotes trade and industry in the region, said he hoped that Volvo would resume production of biogas cars.

"But there are a lot of big economic interests behind ethanol," Varmby said. He was alluding to the generous subsidies farmers and biofuels producers in Europe and the United States earn for growing and processing crop fuels.

Chemically, biogas is the same as natural gas from fossil fuels, but its manufacture relies on a process where bacteria feed on fecal waste for about three weeks in an oxygen-free chamber. The result is two-thirds methane and one-third carbon dioxide, as well as a nutrient-rich residue that can be used as soil or construction material.

Once the methane is purified, it is pumped through Goteborg's network of gas pipelines to specialized filling stations, where it is pressurized for delivery. Any car with an engine and tank configured for compressed natural gas can use biogas.

After each fill-up, the corresponding amount of biogas is injected into the natural gas grid as an offset, said Bo Ramberg, chief executive of FordonsGas, which is based in Goteborg and operates the largest chain of biogas filling stations in Scandinavia.

The idea is that the amount of gas used by vehicles is offset by the gas produced by organic waste.

Ramberg, formerly an executive at Volvo, said he left the company about a decade ago to start FordonsGas when he spotted an opportunity to promote the infrastructure needed to deliver biogas to drivers.

"We're looking to certify the emissions from the entire life cycle of biogas production and use," Ramberg said.

"But we already strongly believe that biogas is the best fuel for lower emissions - no discussion about it," he said.

FordonsGas, which is half-owned by Dong Energy, a Danish company, makes a small profit and is continuing to invest in new biogas filling stations, Ramberg said.

Biogas promoters acknowledge that the decision by Volvo to halt production of biogas cars had dealt the technology a serious blow.

But they said decisions by Mercedes and Volkswagen to introduce a new models of biogas cars in Sweden this year, and rebates and tax breaks for drivers, could still invigorate sales of the cars and fuel.

Biogas as a vehicle fuel is also available in Switzerland, France, Germany and Austria, but Sweden is the leading user in Europe, said Irmgard Herold, an analyst at New Energy Finance in London.

Many people in Goteborg remain optimistic about the virtuous link they have created between waste and secure energy supplies.

Ola Fredriksson, an engineer at Gryaab, the sewage facility in Goteborg, said that what an average person flushed down the toilet each year created enough biogas to drive 120 kilometers, or 75 miles.

"If the oil price keeps on going up, and people are prepared to pay more for renewable energy, then it will make our company interested in producing more biogas," he said. "We have the capacity.'

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The Conspicuous Colors Of Chameleons

For years scientist have known that chameleons’ ability to change color served three purposes: camouflage, body heat regulation, and social communication. However, the most widely accepted hypothesis as to what drove this adaptation, up until now, was camouflage, but some recent research has brought new light as to why chameleons have become know as the color changers that they are, and scientist now believe that social communication is the main driver behind this adaptation.

There are more than 160 species of Chameleons known, and their body size and shape varies widely from 1 inch up to 31 inches. Most of them can be found in Africa, Madagascar and other tropical areas. While chameleons have many unique physical features, such as there independently moving eyes and extremely long tongues, their ability to change color has always been the most fascinating.

Photo by sukanto debnath

All chameleons are able to change color, with different species exhibiting different color ranges that include pink, blue, red, orange, green, black, brown and yellow.

Color Change

Chameleons have specialized cells, collectively called chromatophores, that lie in layers under their transparent outer skin. The cells in the upper layer, called xanthophores and erythrophores, contain yellow and red pigments respectively. Below these is another layer of cells called iridophores or guanophores, and they contain the colourless crystalline substance guanine. These reflect, among others, the blue part of incident light. If the upper layer of chromatophores appears mainly yellow, the reflected light becomes green (blue plus yellow). A layer of dark melanin containing melanophores is situated even deeper under the reflective iridophores. The melanophores influence the ‘lightness’ of the reflected light. All these pigment cells can rapidly relocate their pigments, thereby influencing the colour of the chameleon.
- Wiki:Chameleon

Photo by Pashka

The study

Scientists ran experiments on 21 species of southern African dwarf chameleons to figure out why these color-changing abilities formed.

If camouflage drove the evolution of color change, the species of chameleon that display the greatest diversity of skin coloration would have the greatest variety of backgrounds to match their habitats.

Photo by buckoven

One hypothesis is social communication primarily drove the evolution of color change. In that scenario species that possessed the widest range of color change would have the flashiest displays.

So the scientists pitted male chameleons against each other and measured the range of their color change.

The findings

“We could use that difference in male dominant and submissive color as a measure of their ability to change color,” Stuart-Fox said.

“We found that the species that change [the] most are the ones with the most conspicuous displays, whereas there was no relationship between how much they change color and the variety of backgrounds they had to match,” she said.

Photo by Charlotte Hay

“The study is particularly interesting insofar as it helps clarify a common misconception that is in textbooks and [is] widely perceived by the public and scientists alike: that chameleons are masters of camouflage,” said Roger Hanlon, a senior scientist at the Marine Biological Laboratory in Woods Hole, Massachusetts.

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