King Tut had club foot, malaria: study

The celebrated pharaoh Tutankhamen had a club foot, walked with a cane and was killed by malaria, according to a study that used modern genetic testing and computer technology.

Researchers from Egypt, Italy and Germany used DNA testing to draw "the most plausible" family tree to date for Tutankhamen and computerised tomography (CT) scans to determine that the pharaoh and his forebears were unlikely to have had the feminine physiques they are depicted within 3000-year-old artefacts.

They analysed DNA taken from 11 mummies, including the boy king himself, and scanned all but one of the mummies to determine if they were related, look for evidence of genetic disorders and infectious diseases, and determine what killed Tutankhamen at the age of 19.

Tutankhamen, who is often referred to as King Tut, died just nine years into his reign, which lasted from 1333 BC to 1324 BC.

"Many scholars have hypothesised that Tutankhamen's death was attributable to an accident, such as a fall from his chariot or a kick by a horse or other animal; septicaemia or fat embolism secondary to a femur fracture; murder by a blow to the back of the head; or poisoning," the study's authors write.

But genetic testing found evidence that Tutankhamen had been infected with Plasmodium falciparum, the parasite that causes an often deadly form of malaria.
Club foot

The scans and genetic fingerprinting carried out on Tutankhamen also showed he had several disorders, some of which ran in the family. They included a bone disease and a club foot.

So rather than the majestic ruler that Tut is often depicted as, the pharaoh was probably "a young but frail king who needed canes to walk because of the bone-necrotic and sometimes painful Koehler disease II, plus oligodactyly (hypophalangism) in the right foot and clubfoot on the left," they write.

Tut's many disorders probably weakened his immune system over time, and the researchers believe he might have died when, in his immuno-deficient state, he sustained a "sudden leg fracture, possibly introduced by a fall," which snowballed into a life-threatening condition when he contracted malaria.

Experts call for 'resilience thinking'

Society needs to learn from resilient ecosystems if it is to better cope with unanticipated shocks in the future, say experts.

The call comes ahead of a conference on resilience begins today at the Australian National University in Canberra, hosted by Australia 21.

"Resilience is about how we [as individuals or as organisations or societies] bounce back from adversity, from shocks", says Dr Steven Cork, who leads Australia 21's Resilience Project.

He says thinking about resilience is important because humans are facing many challenges that are beyond our control to predict and control - from climate change to the global financial crisis.

"We keep being hit by more and more things that we weren't anticipating," says Cork.
Learning from ecology

Cork says resilience is a feature that has been recognised in the field of ecology for many years.

He says one feature of a resilient ecosystem is that it can more easily bounce back from a shock when it has the ability to keep functioning if one part collapses.

But, says Cork, the typical society relies on centralised networks that are vulnerable to threats.

"It's all dependent on one or a few people or agencies. If they collapse then the whole system collapses," says Cork.

'safe' virus proposed as vaccine

A company is planning to inject people with an HIV vaccine made of the deadly virus itself, albeit a deactivated version.

Vaccines against many viruses, including flu, are made from deactivated versions of those viruses, but such an approach was previously dismissed as too risky in the case of HIV.

Now VIRxSYS of Gaithersburg, Maryland, is resurrecting the controversial approach, thanks to successful tests of a similar vaccine against SIV – also known as simian HIV – in monkeys.

"We said 'let's use HIV against itself', and that's what we're doing," says Gary McGarrity, VIRxSYS's vice president of scientific and clinical affairs.
High-profile flop

The idea of turning to the virus itself follows years of frustration with prospective vaccines based on viruses other than HIV, such as adenoviruses that cause colds.

Adenoviruses have been modified to carry parts of the HIV virus. Although there were hints of modest success with one such vaccine last year, the previous best bet proved to be a high-profile flop in 2007, during a trial dubbed "STEP".

Crucially, the new tests in monkeys suggest a vaccine based on HIV itself might be more effective than these attempts. The company is planning to apply for approval to perform human trials.

VIRxSYS says such trials would initially be only in people who already carry the virus, rather than in healthy people at risk of infection. This will certainly make for a less controversial trial, as it would avoid any chance of the vaccine going "live" and infecting people who didn't have HIV to start with.

Warmer seas may rob corals and rainforests of clouds

Rising ocean temperatures might leave coral reefs in seriously hot water – without clouds for protection.

Five years ago Graham Jones and his team at Southern Cross University in Lismore, New South Wales, Australia, demonstrated that algae living in coral tissue produce a gas called dimethyl sulphide (DMS). When released into the atmosphere, DMS helps clouds form over coral reefs. Jones says that the clouds block sunlight and cool the sea.

His team have now discovered that a rise in ocean temperature of only 2 °C causes some algae to stop producing DMS. As a result, fewer clouds will form over the coral, thinks Jones, allowing more sunlight to shine on the water, warming it still more.
Jones and his colleague Esther Fischer studied staghorn corals taken from Heron Island in Queensland, Australia, by subjecting them to different water temperatures in the lab while recording the amount of DMS released into the atmosphere.

When the water temperature rose from the annual mean of 24 °C to 26 °C, no DMS was released, says Jones.

Normally, DMS exuded by coral algae is picked up by the wind and carried up into the atmosphere. The gas is oxidised and forms small sulphur aerosol particles that attract water vapour and produce clouds.

The findings support Jones's past work, which found that extreme warming of water around the Great Barrier Reef in the early 1990s led to lower DMS levels in the water. But he says this is the first study to measure the effect of water temperature on the amount of DMS entering the atmosphere.

The other climate culprits

IN JUNE 1783, lava and gases began pouring from the Laki fissure in Iceland in one of the biggest and most devastating eruptions in history. Poisonous gases and starvation killed a quarter of Iceland's population. The effects of the eight-month-long eruption were felt further afield, too. In the rest of Europe, a scorching summer of strange fogs was followed by a series of devastating winters. In North America, the winter of 1784 was so cold the Mississippi froze at New Orleans.

At the time, French naturalist Mourgue de Montredon suggested the eruption might be to blame, but two centuries passed before scientists started to work out how gas and dust from volcanoes affect climate. The main culprit is sulphur dioxide, which has a cooling effect. Laki pumped an estimated 120 million tonnes of the stuff into the atmosphere, cooling the northern hemisphere by as much as 0.3 °C over the next few years.

Nowadays, we are pumping out amounts of sulphur dioxide each year comparable to Laki's emissions. Human emissions rose rapidly over the 20th century, peaking at an estimated 70 million tonnes a year in the 1990s as developed countries cleaned up their act. Even such huge amounts, however, have not been enough to stop global warming: the cooling effect has been more than offset by the warming effect of carbon dioxide and other pollutants.

We are only now beginning to understand the effects of some of those other pollutants. One of the major players is black carbon, produced by the burning of everything from dung to diesel. Some recent studies suggest it is one of the biggest causes of warming after CO2 in the short term, contributing to the rapid warming in the Arctic and the melting of Himalayan glaciers.

Giant Meteorites Slammed Earth Around A.D. 500?

Pieces of a giant asteroid or comet that broke apart over Earth may have crashed off Australia about 1,500 years ago, says a scientist who has found evidence of the possible impact craters.

Satellite measurements of the Gulf of Carpentaria (see map) revealed tiny changes in sea level that are signs of impact craters on the seabed below, according to new research by marine geophysicist Dallas Abbott.

Based on the satellite data, one crater should be about 11 miles (18 kilometers) wide, while the other should be 7.4 miles (12 kilometers) wide.

For years Abbott, of Columbia University's Lamont-Doherty Earth Observatory, has argued that V-shaped sand dunes along the gulf coast are evidence of a tsunami triggered by an impact.

"These dunes are like arrows that point toward their source," Abbott said. In this case, the dunes converge on a single point in the gulf—the same spot where Abbott found the two sea-surface depressions.

The new work is the latest among several clues linking a major impact event to an episode of global cooling that affected crop harvests from A.D. 536 to 545, Abbott contends.

According to the theory, material thrown high into the atmosphere by the Carpentaria strike probably triggered the cooling, which has been pinpointed in tree-ring data from Asia and Europe.

What's more, around the same time the Roman Empire was falling apart in Europe, Aborigines in Australia may have witnessed and recorded the double impact, she said.

Space Photo

A cloud of exhaust engulfs a launch pad at Kennedy Space Center in Florida as the space shuttle Endeavour lifts off during the space shuttle program's last scheduled night launch. The launch is the first of the final five launches before NASA retires the space shuttle at the end of 2010.

Endeavour and its crew are on their way to the International Space Station to deliver supplies and help install the new Tranquility node, a pressurized module that will provide additional room for crew members as well as house many of the station's life-support and environmental-control systems.

Super Earth

Pieces of a giant asteroid or comet that broke apart over Earth may have crashed off Australia about 1,500 years ago, says a scientist who has found evidence of the possible impact craters.

Satellite measurements of the Gulf of Carpentaria (see map) revealed tiny changes in sea level that are signs of impact craters on the seabed below, according to new research by marine geophysicist Dallas Abbott.

Based on the satellite data, one crater should be about 11 miles (18 kilometers) wide, while the other should be 7.4 miles (12 kilometers) wide.

For years Abbott, of Columbia University's Lamont-Doherty Earth Observatory, has argued that V-shaped sand dunes along the gulf coast are evidence of a tsunami triggered by an impact.

"These dunes are like arrows that point toward their source," Abbott said. In this case, the dunes converge on a single point in the gulf—the same spot where Abbott found the two sea-surface depressions.

The new work is the latest among several clues linking a major impact event to an episode of global cooling that affected crop harvests from A.D. 536 to 545, Abbott contends.

According to the theory, material thrown high into the atmosphere by the Carpentaria strike probably triggered the cooling, which has been pinpointed in tree-ring data from Asia and Europe.

What's more, around the same time the Roman Empire was falling apart in Europe, Aborigines in Australia may have witnessed and recorded the double impact, she said.

Telescope Spies Comet

The telescope, which launched in December 2009, will scour the sky for objects that give off infrared light.

"What we're able to see that's different with WISE is the cool dust being blown off the comet by the sun," said the WISE telescope's deputy project scientist Amy Mainzer.

Cold objects emit more energy at long infrared wavelengths than warm objects do, so WISE is particularly sensitive to icy comets and cool, rocky asteroids, she added. (See comet and asteroid pictures.)

"We can learn a great deal about the physical properties of comets, such as their size and how big their dust particles are," Mainzer said.

The last time the entire sky was mapped in infrared light was in 1983, using the Infrared Astronomical Satellite, or IRAS, which had a 62-pixel sensor. WISE uses a four-million pixel—or four-megapixel—sensor.

"I would say it's the difference between an old-fashioned landline phone and an iPhone," Manzier said.

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Save Our Earth, Let’s Go Green

Fibers cradle a planet-like ball in an award-winning image meant to convey that Earth's future is in our collective hands.

Harvard University's Sung Hoon Kang submerged tiny plastic fibers—each only 1/500 as big as a human hair—in an evaporating liquid, where they spontaneously and cooperatively supported the small green ball.

"Using the image, I tried to describe cooperative efforts across the world to save our Earth by going green," Hoon said.

The shot was selected as best photograph in the 2009 International Science and Engineering Visualization Challenge. The annual contest, sponsored by the National Science Foundation and the journal Science, award outstanding artistic efforts to visualize complex scientific concepts. (See some of last year's winners.)

Spirit to remain stuck in Martian sand

NASA has admitted defeat saying efforts to free the Spirit rover bogged down by Martian sand were over and instead the plucky robot was hunkering down to brave the harsh Mars winter.

"Spirit is not dead; it has just entered another phase of its long life," says Doug McCuistion, director of the Mars Exploration Program at NASA headquarters in Washington.

"It looks like Spirit's current location on Mars will be its final resting place."

Earlier this month NASA celebrated Spirit's bountiful, six-year stint on the Red Planet, way longer than the three months it was forecast to last.

But in April the tireless, 180-kilogram, six-wheel robot broke through a crusty surface layer and hit sand at one edge of the Troy crater, west of the Home Plate plateau, in the Martian southern hemisphere.
Power problems

All attempts to extricate it have failed. Dead in its tracks, Spirit cannot shake off the Martian dust that has been slowly accumulating on its solar panels, preventing its batteries from recharging.

Now with winter arriving in May, the Spirit will not get enough light from the Sun to be able to recharge, says NASA.

"Solar energy is declining and expected to become insufficient to power further driving by mid-February. The rover team plans to use those remaining potential drives for improving the rover's tilt."

NASA hopes to be able to tilt the Spirit enough to keep it going through the winter.

"Getting through the winter will all come down to temperature and how cold the rover electronics will get," says project manager John Callas.

"Every bit of energy produced by Spirit's solar arrays will go into keeping the rover's critical electronics warm, either by having the electronics on or by turning on essential heaters."

Even though it will be stationary, Spirit will still be able to carry out studies and has already begun to monitor tiny wobbles in the rotation of Mars to gain insight about the planet's core.

"If the final scientific feather in Spirit's cap is determining whether the core of Mars is liquid or solid, that would be wonderful," says researcher Steve Squyres.

Ancient birds grew fat and lazy

The flighted ancestor of birds such as the Australian emu and cassowary became too heavy to fly after the extinction of dinosaurs made it safer to forage for food, suggests a new study.

The finding by Australian National University (ANU) biologist Dr Matthew Phillips and colleagues at Massey University in New Zealand also answers the mystery of how flightless birds managed to disperse across oceans.

Their work, published in the latest Systematic Biology journal, follows on from recent work that raised uncertainty about the "single ancestor" theory of the group of flightless birds, known as ratites.

Phillips, of the ANU's Research School of Biology, says ratites are a group of flightless birds that include the Australian emu and cassowary, African ostrich, New Zealand's kiwi and now-extinct moa, rhea from South America and the extinct elephant birds of Madagascar.

The study used molecular dating of the mitochondrial DNA from the moa, which stood 2.5 metres tall and weighed up to 250 kilograms, and found its closest relative to be the tinamous - a flighted bird the size of quail, found in South America.

Previously it was thought ratites all shared a common flightless ancestor about 80 million years ago and their worldwide dispersal occurred before the supercontinent of Gondwanaland broke up.

But Phillips says the problem with this theory was that much of the continental break-up occurred well before the proposed common ancestor.

Let the sunlight in on climate change

The IPCC was tasked by the governments of the world to deliver an encyclopedic consensus on the state of knowledge about one of the most far-reaching yet divisive questions of our time. And this grouping of thousands of scientists, taking time out from their regular jobs has, for more than two decades, delivered. Thanks to the IPCC's work, the world's nations have come together to decide that we must prevent our planet warming by more than 2 °C - even if achieving that goal is proving difficult, to say the least.

The serious error, reported here two weeks ago, that led to the inclusion in an IPCC report of mistaken claims about how fast Himalayan glaciers are melting is undoubtedly damaging to the panel's reputation. But it does not in any way undermine the conclusion that human-induced climate change is happening, is dangerous and requires urgent action.

However, the IPCC's heroic days are probably over. The case for anthropogenic climate change has been established; the Nobel prize is won. So it is time for a rethink of where the IPCC is going, and what its future role should be. Two years ago, in the aftermath of the last major assessment report, many scientists argued that the task should have begun then. It is no less urgent now.

We still need the IPCC to serve as a seeker of truth whose deliberations are open to scrutiny. There is plenty of new science to assess. But it makes little sense to have to wait six years between assessments: though reflection, and time for the replication of findings, are essential, why not have an annual report?

The organisation also needs to be more focused on providing the science that will address emerging policy challenges. Its best recent work is in its special reports on topics such as aircraft emissions. A special report on geoengineering would be invaluable, as would a dispassionate assessment of how to measure and verify national greenhouse gas emissions, and carbon sinks such as soils and forests.

Should the IPCC remain as an intergovernmental body - in other words, answerable to national governments from around the world? Yes, it probably should. It was the US, during the Reagan presidency back in the 1980s, that insisted on this. At the time, many scientists were dismayed, fearing political interference in the panel's published reports. But these fears largely failed to materialise, and the fact that national governments all sign off each report has reinforced the IPCC's authority. But public attitudes to science are changing. The IPCC was established before the internet revolution. Like it or not, its closed world of peer review is no longer possible, let alone desirable.

The job of scientists is to test theories to destruction, which inevitably makes science adversarial at times. Dispute is good; consensus stultifies. It is neither surprising nor disturbing that disputes about the science break out, within the IPCC and outside it, and such disagreements need to be out in the open.

Supernovae linked to gamma ray bursts

Scientists have discovered a new way of detecting gamma ray bursts while using radio telescopes to observe supernovae.

The researchers say this may provide new clues in understanding how some supernovae explode and how they may be related to gamma ray bursts.

Gamma ray burst events are among the most powerful and violent explosions in the universe, emitting mostly gamma and x-rays.

Supernovae are much smaller by comparison typically emitting light at visible wavelengths, at speeds approaching 3% the speed of light.

One group of supernovae known as type Ib/c have previously been associated with gamma ray bursts, but their optical and radio emissions have never shown evidence of travelling close to the speed of light - a true sign of gamma ray bursts.

Now a report in the journal Nature suggests long duration gamma ray bursts are a rare sub-class of type Ib/c supernovae.
Powerful engines

Using radio telescopes, the researchers found that material ejected from supernova 2007gr - located in the galaxy NGC1058 - is moving at more than 60% the speed of light.

"These relativistic jets imply the presence of powerful central engines driving the outflows," says radio astronomer Dr Megan Argo of Curtin University of Technology in Perth.

"These central engines are thought to involve the accretion of matter either into a black hole or onto a neutron star."

Argo says the strong magnetic forces inside the neutron star tightly focus the ejected material into high energy jets, which can be measured by the radio telescopes.

"It's the same process believed to be at the heart of gamma ray bursts," she says.

According to Argo, the findings suggest that some type Ib/c supernovae may produce mildly relativistic jets.

High-Tech Energy "Oasis" to Bloom in the Desert?

A renewable-energy "oasis" slated to be built in 2010 may serve as a proving ground for new technologies designed to bring green living to the desert.

The planned research center is part of the Sahara Forest Project—but that doesn't mean it'll be built in Africa. Sahara means "desert" in Arabic, and the center is meant to be a small-scale version of massive green complexes that project managers hope to build in deserts around the globe.
Experts are now examining arid sites in Australia, the U.S., the Middle East, and Africa that could support the test facility.

"The Sahara Forest Project is a holistic approach for creation of local jobs, food, water, and energy, utilizing relatively simple solutions mimicking design and principles from nature," said Frederic Hauge, founder and president of the Norwegian environmental nonprofit the Bellona Foundation.

For instance, special greenhouses would use hot desert air and seawater make fresh water for growing crops, solar energy would be collected to generate power, and algae pools would offer a renewable and easily transportable fuel supply.

In addition, planting trees near the complex would trap atmospheric greenhouse gases such as carbon dioxide while restoring any natural forest cover that has been lost to drought and timber harvesting.

(Related: "Africa-wide 'Great Green Wall' to Halt Sahara's Spread?")

"From my perspective as an environmentalist, this could be a game changer in how we produce biomass for food and energy, and how we're going to provide fresh water for the future," Hauge said. "I've never been so engaged and fascinated as I am now."

Sea level data spanning 35 million years pulled from 6,000-foot hole

To better understand how rising sea levels could impact the planet, researchers have drilled more than 6,000 feet into the Earth's crust--making the deepest hole in scientific ocean drilling history. In doing so, they retrieved a 35-million-year record of sea level fluctuations.
For eight weeks beginning in November 2009, off the coast of New Zealand, an international team of 34 scientists and 92 support staff and crew on board the scientific drilling vessel JOIDES Resolution (JR) were at work investigating sea level change in a region called the Canterbury Basin, the U.S. National Science Foundation said in a news statement about the venture.

The JR is one of the primary research vessels of an international research program called the Integrated Ocean Drilling Program (IODP). The program is supported by the NSF and Japan's Ministry of Education, Culture, Sports, Science, and Technology.

"At present 10 percent of the world's population lives within 10 meters [33 feet] of sea level. Current climate models predict a 50-centimeter [20-inch] to more than one-meter [39 inches] rise in sea level over the next 100 years, posing a threat to inhabitants of low-lying coastal communities around the world," NSF said.

To better understand what drives changes in sea level and how humans are affecting this change, scientists are "looking to our past for answers and digging back as far as 35 million years into the Earth's history to understand these dynamic processes," said Rodey Batiza of the NSF's division of ocean sciences.

Drug could turn soldiers into super-survivors

A LUCKY few seem to be able to laugh in the face of death, surviving massive blood loss and injuries that would kill others. Now a drug has been found that might turn virtually any injured person into a "super-survivor", by preventing certain biological mechanisms from shutting down.

The drug has so far only been tested in animals. If it has a similar effect in humans, it could vastly improve survival from horrific injuries, particularly in soldiers, by allowing them to live long enough to make it to a hospital.

Loss of blood is the main problem with many battlefield injuries, and a blood transfusion the best treatment, although replacing lost fluid with saline can help. But both are difficult to transport in sufficient quantities. "You can't carry a blood bank into the battlefield," says Hasan Alam of Massachusetts General Hospital in Boston. "What we're looking for is a pill or a shot that would keep a person alive for long enough to get to them to a hospital."

Mars Rover to Roam No More

So mission managers announced Tuesday that the rover will stay put, spending the rest of its days conducting science from its current location inside the crater, where its wheels can move only a few inches.

That crater proved to be "a golfer's worst nightmare," Doug McCuistion, director of the Mars Exploration Program, told reporters Tuesday at a press briefing in Washington, D.C.

"It's a sand trap that, no matter how many strokes you take, you just can't get out."
Now, instead of planning an escape, rover drivers will use the craft's limited mobility to reposition the probe, giving Spirit a better chance of surviving the oncoming Martian winter.

"In the past we've been able to drive the rover to tilt its solar arrays toward the north and maximize sunlight," said rover project manager John Callas, based at NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California.

Right now Spirit has "an unfavorable tilt," about nine degrees toward the south, he said.

"If we can't improve the tilt, we'll drop below the power levels we need to maintain daily activities."

In that case, the rover would trigger itself to go into hibernation, and NASA mission managers likely wouldn't hear a peep out of the craft for about six months.

In the meantime, mission managers will continue to communicate with Spirit's twin rover, Opportunity, which is currently motoring toward Endeavour Crater.

Opportunity "is now on approach to an extremely young crater called Concepcion [which] may be the youngest crater a rover has yet encountered," McCuistion said.

Got Aliens in Your Nose?

This week the Royal Society in London is holding a two day meet-up for scientists to talk about the state of our search for extraterrestrial life.

At a lecture today, astrobiologist Paul Davies of Arizona State University told the crowd that he thinks aliens already walk among us. Well, maybe not walk—more like float, or wiggle, or however else bacteria may locomote.
According to the Associated Press, Davies thinks that life from elsewhere in the galaxy has made its way to Earth at several points in human history. It's possible, he says, that alien life is "right under our noses—or even in our noses."

And why not? So many science-fiction writers seem convinced that if aliens of any shape or size were to come to Earth, they'll be bad for humans and hence immediately noticable. Giant robots! Predatory stalkers!! Killer pathogens!!! Yes, Michael Crichton, I'm looking at you.

But that certainly doesn't have to be the case.

For starters, consider the odds of an intelligent race of beings existing elsewhere in the universe.

Year's Best Mars View Tonight

Mars is zooming in for a close approach to Earth tonight, offering backyard astronomers their best views of the red planet until 2014.

For the past few months Mars has appeared at night as a ruddy, starlike beacon rising in the east.

Tonight Mars will pass within 61 million miles (98 million kilometers) of Earth—close enough for well-equipped sky-watchers to make out details on the Martian surface.

"With a small telescope of about 6 inches (15.2 centimeters), the polar ice caps and other surface features are visible," said Raminder Singh, staff astronomer at the H.R. MacMillan Space Centre in Vancouver, British Columbia.

(Related: "Mars Pole Holds Enough Ice to Flood Planet, Radar Study Shows.")

"Even a pair of binoculars will show it as a disk, as opposed to a star, which looks like a pinpoint of light."

And on January 29 Mars will reach opposition, which means it will rise in the east just as the sun sets in the west, making the red planet visible all night long.

"When opposition occurs, Mars is on the opposite side [of Earth] from the sun. If viewed from above the solar system, the sun, Earth, and Mars would be in a straight path," Singh said.

(Find out what happens when Mars is on the opposite side of the sun from Earth, aka in solar conjunction.)

Adding to the cosmic spectacle, on the night of opposition Mars will appear fairly close to the full moon, and the pair will glide together across the sky.

Mars Easy to See

The exact distance between Mars and Earth changes over time, because the orbits of the planets are not perfect circles, but elongated ellipses.

This orbital setup means Mars makes a close pass by Earth roughly every two years.

In August 2003 Mars made its closest pass by Earth in 60,000 years, swinging by at a mere 35 million miles (56 million kilometers) away. That event created spectacular views for astronomers but also seems to have spawned the recurring "Mars Spectacular" email hoax.

Tonight's approach won't be a particularly close pass. Still, the "flyby" will highlight how easy it is to spot Mars even with the naked eye, Singh noted.

"It's the third brightest object in the night sky, aside from the moon and the star Sirius," Singh said.

"People should really go outside and look at it, as it's an easy thing to see in the sky."

Running Barefoot Reduces Stress—On Feet

Going barefoot isn't just for strolling on the beach: Running barefoot reduces stresses on your feet and may prevent injuries known to afflict traditionally shod runners, a new study says.

In his bestselling book Born to Run, Christopher McDougal revealed that the best long-distance runners on the planet may be Mexico's Tarahumara Indians, who race barefoot or in thin sandals through the remote Copper Canyons of Chihuahua state.

The new study used high-speed video and a bathroom scale-like device called a force plate to digitally dissect the moment-by-moment stresses on the feet of 63 runners as they ran barefoot.

The research revealed that running barefoot changes the way a person's feet hit the ground.

Runners in shoes tend to land on their heels, so sports shoe makers have spent years designing footwear with gels, foams, or air pockets in the heels to reduce the shock of impact.

But barefoot runners more often land on the forefoot, near the base of the toes. This causes a smaller part of the foot to come to a sudden stop when the foot first lands, allowing the natural spring-like motion of the foot and leg to absorb any further shock.

"This form of landing causes almost no collision force," lead author Daniel Lieberman, an evolutionary biologist at Harvard University, said in an email.

Not that the benefits of barefoot running should be a surprise, he added: "Humans were able to run for millions of years without shoes or in just sandals."

(Related: "Humans Were Born to Run, Fossil Study Suggests.")

Running on Sticks and Stones

The work, published online today by the journal Nature, is "really interesting and useful," according to coach, exercise physiologist, and author Jack Daniels.

"There is no doubt impact is a major source of injury," Daniels said via email, and reducing injuries is a key goal of all runners and coaches.

Daniels himself has done much of his own running barefoot.

"I eventually got to where I could go barefooted for five miles [eight kilometers] on a concrete sidewalk," he said, though he admits he prefers grass and well-cushioned tracks.

Even the latter, he added, takes practice.

"One main problem is the abrasion factor," he said. "You have to toughen up the skin on the bottom of your feet."

Luckily the choice won't be between shoes or no shoes for long. Shoe companies have been scrambling to design "minimalist" footwear that still protects the feet from rocks, thorns, and broken glass while allowing people to run more naturally.

Our Solar System May Have Millions of "Twins"

While that might not sound like much, the find suggests that several hundred million star systems look a lot like the one we call home, the study authors say.

The research is based on surveys of stars with gas giant planets—similar to Jupiter and Saturn—that orbit far from their stars.

As in our solar system, vast distances stretch between these stars and their gas giants. This creates ample room for rocky planets to thrive in the stars' habitable zones, the regions where liquid water can exist.

And that boosts the likelihood that other Earths, and maybe even other forms of life, abound in the Milky Way.

"For the first ten years of planet hunting, we were feeling a bit worried—other systems looked so different from our own solar system," noted Debra Fischer, an astronomer at San Francisco State University who was not involved in the research.

"[These] results are reassuring us that there are solar systems akin to our own. This is real data that strengthens the hypothesis that there are many habitable worlds like our Earth."

Cosmic Magnifying Glass

Astronomers think that gas giants generally form farther from their stars, while rocky worlds like Earth form closer in.

But in some star systems it's thought that gas giants migrate inward, knocking any smaller planets out of their orbits or destroying the rocky worlds outright.

Meanwhile, star systems like ours have gas giants in stable outer orbits.

"In these systems there is room for terrestrial planets to prosper and not get knocked out of their orbits," said study co-author Andy Gould, an astronomer at Ohio State University. 

What's more, studies of Jupiter suggest that outer gas giants can act as gravitational shields, protecting inner rocky worlds—and any life-forms on them—from frequent asteroid impacts.

To find such star systems, nearly a hundred scientists joined forces as part of the Microlensing Follow-Up Network, or MicroFUN, to scour the galaxy using a technique called gravitational microlensing.

In this method, when one star passes in front of another, as seen from Earth, the nearer star's gravity acts like a lens, bending and magnifying the more distant star's light.

If the nearer star has orbiting planets, keen-eyed observers can spot the subtle clues of their presence in the magnified light.

If all the stars in the Milky Way hosted solar system twins, astronomers should have found at least six such systems them by now, according to a statistical analysis of four years' worth of microlensing data.

But so far, only one other system like ours has been spotted: In 2006 astronomers found a star with its own versions of Jupiter and Saturn.

That means just 15 percent of the galaxy's stars must have solar systems like ours, Gould and colleagues announced this week at the 215th meeting of the American Astronomical Society in Washington, D.C.

New Sex Hormone Found

A new human sex hormone has been found, a new study says. The naturally occurring substance could lead to the long-sought male birth control pill, researchers cautiously speculate.

Gonadotropin-inhibitory hormone (GnIH)—first identified in birds about a decade ago—was recently discovered in the hypothalamus of the human brain. The hypothalamus produces hormones that regulate sleep, sex drive, body temperature, and more.

GnIH suppresses another hormone—gonadotropin-releasing hormone (GnRH)—which spurs the release of additional hormones, which prime the body for sex and reproduction. So scientists cautiously suggest that contraceptives based on the newfound hormone could someday be possible.

"That is an idea we've toyed with," said study co-author George Bentley, a biologist at the University of California, Berkeley. But "we don't know enough about it yet."

Louis DePaolo, the U.S. National Institutes of Health's Reproductive Sciences Branch chief, agreed "it's too premature" to consider a male birth control pill.

GnIH has been known in animals since 2000, and it was known that humans have a GnIH gene, but until now it was a mystery whether humans actually produce the hormone and what its role is.

The researchers, however, extracted GnIH from five human hypthalumuses and proved that the it affects nerve cells that produce the GnRH, the fertility-boosting hormone.

Nuclear safety: When positive is negative

WHEN news spread in December 2007 that an ageing nuclear reactor in Canada might shut down for much longer than its scheduled two weeks, the world caught its breath. The reactor, at Chalk River in Ontario, is the world's biggest supplier of radioactive isotopes for medical use, and diagnostic tests for cancer and heart disease were put on hold while radiologists scrambled to find alternative supplies. It was called a crisis. All the while, lay people couldn't help but wonder: did no one foresee this? Did no one think that this half-century-old reactor might someday need to be replaced?

As it happens, not only did someone think about it, they designed and built its successors right next door. Maple 1 and Maple 2 are two brand-new reactors, constructed at a combined cost of over C$350 million ($330 million) specifically to produce medical radioisotopes. A single Maple reactor can supply the world's total current needs; the second one is a back-up to keep the supply flowing during routine repairs.

But the sad truth is that the Maples have never been officially switched on, and the chances are they never will be. This has led to a furious row over who is to blame for this costly and embarrassing debacle. Many in the nuclear industry point the finger at Canada's nuclear regulator. The regulator's view is that the reactors' manufacturer failed to deliver a crucial safety feature that it had promised would underpin the design.

Others blame the Canadian government for killing off the project before crucial technical questions had been resolved; in May 2008 it announced, to everyone's surprise, that the Maples were being shuttered for good. "It makes absolutely no sense to me," says Jatin Nathwani, an engineer at the University of Waterloo, Ontario, who gave evidence to a parliamentary committee now looking into the affair. It's time the Canadian government reversed its decision, says Nathwani: "If the will was there, the Maples could be brought back in six to 18 months, with just one phone call from the prime minister."

Radioisotopes have a vital role to play in modern medicine. They are used in almost 40 million medical procedures each year, mostly for treating and diagnosing diseases such as cancer and heart disease. Over 80 per cent of the diagnostic procedures rely on technetium-99m, a short-lived isotope that is produced by bombarding uranium-235 with neutrons inside a reactor (see diagram).

Deep-sea snail shell could inspire next-gen armour

A deep-sea snail shell's ability to withstand heavy blows could inspire new generation of body armour.

Crysomallon squamiferum, commonly known as the scaly-foot gastropod, was discovered in 1999 in the Kairei "black smoker" field on the Central Indian Ridge, at a depth of 2420 metres.

Christine Ortiz at the Massachusetts Institute of Technology and her colleagues studied the snail's three-layered shell to find out how it defends itself from crab attacks.

To assess the shell's strength and stiffness, they penetrated it with diamond-tipped probe – applying the same amount of force that an attacking crab's claws might use. They then used the data to model the shell's layers and launched a virtual crab attack on it.
Iron hard

It turns out that the snail employs some unique tricks to protect itself. For example, the shell's outermost layer consists of strong particles of iron sulphide created in the hydrothermal vents, each around 20 nanometres across, embedded in a soft organic matrix secreted by the snail. This structure is designed to crack when hit, but in a way that absorbs energy.

Cracks spread only by fanning out around the iron sulphide particles. This "microcracking" not only absorbs energy, it also ensures that larger cracks do not form. What's more, the particles of iron sulphide may blunt and deform intruding claws, the study suggests.

See-Through Goldfish Bred

To create the translucent creature, scientists at Japan's Mie University and Nagoya University crossbred fish that had defects in the gene that regulates pigment, or color.

The resulting mutant fish's organs are all plainly visible, Yutaka Tamaru, a life science researcher at Mie University, said via email.

Tamaru said the fish could act both as a living textbook in biology classes and as a tool for medical researchers.

For instance, scientists could watch in real time how an animal's organs develop. They could also get an inside view of how diseases, particularly tumors, progress in the body.

"As this goldfish grows bigger, you can watch its whole life," Tamaru said.

The translucence doesn't harm the goldfish or shorten its life span, he added.