Titan Forecast: Cold, Drizzly Mornings

Methane drizzles down every morning on Titan, according to a new study of Saturn's largest moon.

The rain is probably widespread across Titan and may even close the loop in a methane cycle that closely resembles the water cycle on Earth, the researchers suggest..

Scientists involved with the Huygens probe, which landed on Titan's surface in late 2004, have long suspected such an atmospheric cycle.

"The most important part of these results is that there is a way to monitor methane condensation from ground-based telescopes," said Mate Adamkovics of the University of California at Berkeley, who led the new research.

"Monitoring how often and to what extent the drizzle occurs might be an indication of seasonal changes on Titan that is more sensitive than watching other types of clouds come and go."

The results will be published in this week's issue of the journal Science.

Exotic Moon

Titan is a mysterious and alluring ball of rock and ice surrounded by a thick, orange, methane-heavy atmosphere.

Some scientists believe that the moon is a likely place to harbor alien life. One reason is that several studies have suggested that Titan has long-lasting lakes most likely made of methane.

On Earth, methane is produced in gas form through biological reactions such as digestion. It can exist as a liquid only under very high pressures.

But at about minus 290 degrees Fahrenheit (about minus 180 degrees Celsius), the surface of Titan is so frigid that methane doesn't need pressure to remain in liquid form.

Using ground-based telescopes and computer models, Adamkovics and his colleagues found a solid methane cloud 15 to 21 miles (25 to 35 kilometers) from Titan's surface.

A constant methane rain pelts Xanadu, the moon's brightest continent, each morning, the researchers discovered.

It's the first time researchers have seen differences between day and nighttime weather on Titan, Adamkovics pointed out.

"They were unexpected, because day-to-night temperature changes are expected to be small," he said.

Still Mysterious

Martin Tomasko, an astronomer at the University of Arizona in Tucson who designed Huygens' camera system, has long suspected methane smog and condensation occurred on Titan.

He has proposed that methane rains from Titan's sky as a thick, tarry gunk. The chemical then travels through channels until it reaches reservoirs visible as dark patches on the moon's surface.

The exact nature of the dark patches remains in dispute, however.

If methane rain is indeed widespread, it could be the main method that atmospheric methane returns to the surface, the study authors write.

But Adamkovics said there's still a long way to go to understand the process.

"Many predictions are being made, but we are far from conclusions," he said, "and I would wager that more surprises are going to be discovered before we have a textbook description of Titan's atmospheric cycling."

Rare Gorillas at Risk as Rebels Seize Congo Park

Heavy fighting continues to rage in the Democratic Republic of the Congo's (DRC) troubled Virunga National Park, one of the last remaining homes for rare mountain gorillas.

On Sunday rebels loyal to renegade general Laurent Nkunda—who have been clashing with DRC military forces in the area since September 3—took control of the park's gorilla sector.

The fighting has sparked further fears for the safety of the critically endangered mountain gorillas, which have been left largely unprotected for more than a month, ever since the clashes forced rangers to evacuate the park.

Today the fighting between rebels and the Congolese army heated up near Bukima, the park's main gorilla monitoring station.

Rangers could also hear the exchange of heavy gunfire near park headquarters at Rumangabo, according to Norbert Mushenzi, director of Virunga's gorilla sector for the Congolese Institute for the Conservation of Nature (ICCN).

"Rangers and local inhabitants are fleeing from all around the park, and the mountain gorillas are totally unprotected," Mushenzi said.

"This whole situation is precarious and frustrating."

Rebels vs. Rangers

About 700 wild mountain gorillas remain in the world, roughly 380 of which live in the Virunga Volcanoes Conservation Area shared by the DRC, Rwanda, and Uganda.

Of these, about 120 are found in the DRC.

But rangers there have been able to track only one family of gorillas since the fighting started five weeks ago, and they have yet to account for 54 of the region's 72 habituated gorillas.

Until last week the situation had appeared to be calming, and rangers were hoping to re-enter the sector to track the gorillas.

But last Friday rangers who had been monitoring gorillas from a post inside the park had to flee when the rebels reportedly tried to force them to become combatants.

Rebel leader Nkunda, who is an ethnic Tutsi, maintains that the government is collaborating with ethnic Hutu rebels hiding in the DRC who are accused of involvement in the 1994 genocide against Tutsis in neighboring Rwanda.

On September 3 the rebels surrounded two ranger stations inside Virunga. The men seized rifles and communications equipment and forced park workers and their families to evacuate.

Since then the rebels have consolidated their grip on the park, conservationists say.

"The army seems to be weakening vis-à-vis the rebels—and this does not bode well for the gorilla sector at all," said Samantha Newport, a spokesperson for WildlifeDirect, an environmental group that supports the DRC rangers.

Fighting for Control

Conservationists said control of the park is important for the rebels.

"The gorilla sector is a key strategic point in this conflict. The rebels want to control it and have access to neighboring countries to replenish their materials and equipment," said Emmanuel de Merode, head of WildlifeDirect.

"The mountain gorillas are stuck right in the middle."

At least ten gorillas have been killed in Virunga this year, and some of the deaths have been blamed on the rebels.

The worst attack occurred on July 22 when five gorillas, including a silverback, were shot dead execution-style.

That attack was linked to the burgeoning charcoal trade in the park. (Read "Congo Gorilla Killings Fueled by Illegal Charcoal Trade" [August 16, 2007].)

In September a dead infant female was found in the hands of alleged traffickers who are now facing judicial procedures in the city of Goma, just south of Virunga.

Newport said there is a strong possibility that the rebels may soon cut off the road between Goma and park headquarters at Rumangabo, thereby totally isolating the 34 rangers there.

The rangers have removed all valuable tracking equipment from Rumangabo in case the clashes reach the area.

One ranger also died this week in a car accident.

The man was coming back with his colleagues from an anti-charcoal burning patrol when he fell out of the pick-up truck they were riding in. He was taken to a hospital, but later died from brain damage.

Early Venus Had Oceans, May Have Been Habitable

Venus, not Mars, may have been the most likely planet in the solar system to have also developed life, scientists say.

The cloud-shrouded planet most likely started with oceans much like Earth's, which evaporated as Venus heated up, according to new research.

The oceans didn't disappear overnight, said David Grinspoon of the Denver Museum of Nature and Science.

Speaking yesterday at a meeting of planetary scientists in Orlando, Florida, Grinspoon said that preliminary results of new computer models indicate Venus may have retained its oceans for a billion years after it formed, possibly longer.

Prior models had indicated that rising Venusian temperatures had turned the oceans to steam within the planet's first 600 million years.

The extra 400 million years are even more significant than they sound, Grinspoon added, because early Venus was constantly bombarded by asteroids, reducing the likelihood of life.

The new finding suggests that the oceans existed for much longer after the asteroid bombardment tapered off.

"There may have been a sizeable interval when [Venus] was habitable," he said.

Today, however, Venus is about 100,000 times drier than Earth and is 860º F (460º C) at its surface, Grinspoon said.

New Discovery From Venus

Future studies might further refine our understanding how long the planet was habitable.

If samples can be collected from the surface, for example, scientists might find rocks that formed when the planet was wet, Grinspoon said.

Determining how much water remains locked in these rocks may allow scientists to figure out how long ago the planet dried out.

Similarly, studies of Venusian gases could help scientists better estimate the rate at which water was lost into space.

Already such research is playing a role in our understanding of Venusian heating.

At the Orlando meeting, French researcher Jean-Loup Bertaux reported that the Venus Express spacecraft, now orbiting the planet, has discovered a rare form of carbon dioxide never before detected on Venus.

Instead of containing the most common form of oxygen, which has eight protons and eight neutrons, this one has one atom of oxygen with eight protons and ten neutrons.

That causes it to absorb more infrared light than normal carbon dioxide, increasing its strength as a greenhouse gas.

(See a photo of "airglow" created by oxygen in the Venusian atmosphere.)

The upsurge of interest in Venus comes hard on the heels of a recent finding that early Mars might have been colder and drier—and therefore less habitable—than previously believed.

Thunderstorm Gamma Rays Linked to Lightning

The formation of gamma rays—the most energetic form of light—in thunderclouds may be linked to lightning production, a new study shows.

Gamma rays are typically produced by cosmic cataclysms like supernovae, but terrestrial thunderstorms can also energize particles enough to create the powerful rays.

Scientists first spotted gamma rays in thunderstorms in the early 1990s. The Compton Gamma Ray Observatory unexpectedly detected radiation originating from the ground while peering at distant supernovae.

"The fact that they are [even] created in something as garden variety as thunderstorms is a surprise," said Steven Cummer, an electrical engineer and lightning researcher at Duke University in Durham, North Carolina.

Lightning Mystery

How thunderclouds produce the rays has not been explained. Neither has the nature of their apparent link to lightning formation, about which many long-standing mysteries remain.

But a new study led by Teruaki Enoto of the University of Tokyo and Harufumi Tsuchiya of RIKEN, Japan's Institute of Physical and Chemical Research, has provided the best look yet at the phenomena.

The team trained an array of gamma ray detectors on two powerful low-pressure air masses that collided over the Sea of Japan on January 6, 2007.

The researchers found that gamma rays were produced some 70 seconds before a lightning strike. They also determined that gamma bursts, which had been previously measured to last less than a second, could occur for almost a minute.

The findings suggest that whatever triggers gamma rays might also be involved in creating lighting—and that their origin might be tied to powerful particles known as cosmic rays that continually rain down from space.

The work will appear in an upcoming issue of the journal Physical Review Letters.

Cosmic Ray Trigger

In the new study, the researchers provide additional evidence that cosmic rays trigger gamma ray generation by releasing a "seed electron" from an atom of air.

This begins "runaway breakdown"—a theoretical process in which the liberated electron ionizes nearby air molecules. These molecules become accelerated in the very high electric fields inside a thundercloud, which can reach up to ten million volts in strength.

A group of fast electrons is then formed, which can emit gamma rays as they are gradually slowed down by contact with surrounding air molecules.

"Everybody agrees that in some way this basic process of runaway breakdown is involved, but whether it has to be triggered by a cosmic ray [is uncertain]," said Cummer, who did not participate in the new Japanese research.

"It's appealing on some levels, but others have suggested ways that don't necessarily [require] a cosmic ray coming through."

Cosmic rays are constantly raining down onto Earth, so it is difficult to isolate their impact on any single event, he pointed out.

Lightning Link

Still, studying thundercloud gamma rays could eventually unlock some secrets of Earth's weather, the Japanese researchers say.

"One significance of our result is the prospect that we can use these gamma rays as a good probe to understand how the strong electric field develops in thunderclouds and how lightning discharges occur," study lead author Enoto said.

The electric fields in thunderstorms appear to be too weak to form lightning, so scientists have been puzzled by how the bolts form. Cosmic rays have also been suggested as a trigger for the flashes.

The researchers are now looking into the exact connection—if any—between runaway breakdown and lightning, especially if such a link applies only to certain kinds of lightning or in certain areas of storms.

Thundercloud gamma rays could also shed light on more exotic cosmic processes like solar flares, pulsars, and jets from black holes, Enoto added.

"Our result shows that thunderclouds may be a natural particle accelerator," he said. "Thunderclouds could provide a nearby hidden prototype for other energetic cosmic accelerators."

No Radiation Danger

Powerful gamma rays can be dangerous in some cases, since the radiation can reach energies a hundred to a thousand times higher than x-rays used in medical devices, Enoto said.

But storm clouds are unlikely to produce enough radiation to cause any worry.

"The total number of detected gamma rays is so small that the overall radiation dose is meager—perhaps seven orders of magnitude less than that of a single medical radiography shot," he explained.

"So this event, we presume, has little impact on Earth or human bodies."

Steamier Earth Likely, Due to Global Warming

Human activity has long made the bedroom a hot and steamy place. Now, less sexy activities like burning coal and oil—major contributors to global warming—are making the whole planet steamier, a new study says.

Scientists expect the rising humidity to cause heavier rains, stronger hurricanes, and increased human heat stress.

Climate scientists have long predicted that a warmer world will allow more water to evaporate, thus making the planet more humid.

Indeed, several studies have shown trends of increasing surface humidity around the planet, but until now scientists were uncertain what was driving the trend.

The new study combined a fresh data set of surface humidity with climate models, "and actually attribute[s] those trends to human influence," said study co-author Nathan Gillett, a climate scientist at the University of East Anglia in Norwich, England.

He and his colleagues report the findings in tomorrow's issue of the journal Nature.

Stormy, Steamy Future

Climate models predict that increased water vapor in the atmosphere will lead to heavier rains and raise the maximum potential intensity for hurricanes, Gillett noted.

"In heat waves, if the humidity is higher, then that results in larger heat stress on humans," he said.

And increased water vapor will accelerate the warming, said Benjamin Santer, a climate modeler at the Department of Energy's Lawrence Livermore National Laboratory in California who was not involved in the study.

"Our best understanding is as we increase greenhouse gases and warm the atmosphere, we increase the atmosphere's capacity to hold moisture. And water vapor is in itself a potent greenhouse gas.

"Therefore you accelerate the warming," he said.

Steve Sherwood is a climate scientist at Yale University in New Haven, Connecticut, who was not involved in the study. He said the findings are uncontroversial, but the new data set is a boon.

"People haven't really been talking enough about what higher humidity is going to mean in the future," he said, "and part of the reason they haven't been talking about it is that we haven't had very good data."

"They've put out a data set that people can actually use to look at long-term changes," he added.

Global Warming Evidence

Santer of the U.S. Department of Energy led research published recently in the journal Proceedings of the National Academy of Sciences that linked human activity to an increase in atmospheric water vapor. (Gillett was a co-author of that paper.)

Gillett, co-author on the new Nature study, also contributed to a July paper in the journal Nature that linked human activity to changes in rainfall patterns over the past century.

This body of work should silence criticism that the only evidence of global warming comes from surface and ocean temperature records, Santer said. Human influence is prevalent throughout the climate system, he added.

The combined studies should also help scientists more accurately predict Earth's response to increasing levels of greenhouse gases, Gillett said.

For example, he said the models used for the July Nature study underestimated the change in rainfall due to global warming, but that the models do a "reasonably good" job of capturing the humidity changes.

"These results will help to pin down which parts of the hydrological cycle the models can simulate well and which not so well ... and help improve the models," he said.

Nanotech Find Earns Two Europeans Nobel in Physics

Frenchmen Albert Fert and German Peter Grünberg have won the 2007 Nobel Prize in Physics for their discovery of the phenomenon that makes modern-day hard-drive technology possible.

The Royal Swedish Academy of Sciences today announced that the two scientists will equally split the prize "for the discovery of giant magnetoresistance [GMR]," which amplifies small magnetic changes into large electrical signals.

The discovery has made possible the massive hard drives used in modern computers, cell phones, and music players, which store data magnetically.

"The practical benefits of this physics could not be greater," said Phillip Schewe, a spokesperson for the American Institute of Physics. "GMR is at the heart of the multi-billion-dollar hard-drive industry."

"This discovery played a key role in the phenomenal increase in storage capacity and reduction in size of magnetic recording systems that are the essential components of modern consumer products such as iPods and computers," added S.A. Solin, a professor of physics at Washington University in St. Louis, Missouri.

In the prize announcement, the Royal Swedish Academy also said that "GMR can also be considered one of the first real applications of the promising field of nanotechnology."

"Weird" Physics

Hard drives store data by magnetizing extremely small sections of material, similar to how VCRs and tape recorders work. But as more data is stored in the same amount of space, the magnetic signals get weaker.

This fact limited hard drive capacities until Fert, of the Université Paris-Sud in Orsay, France, and Grünberg, of Forschungszentrum Jülich in Germany, independently came across giant magnetoresistance in 1988.

The effect is a far better method for reading stored data, and the first GMR-based hard disks were created less than a decade later.

The scientists uncovered the phenomenon while studying the exact properties of extremely thin stacks of metal.

At just a few atoms thick, the layers were expected to experience unusual quantum effects. Fert and Grünberg found this included magnifying very weak magnetic changes into major differences in electrical conductivity.

"It's just an esoteric, weird type of physics, but a force that can be exploited to make valuable products," Schewe said.

"This is a wonderful example of how an accidental scientific discovery can have an extraordinary impact in technology—a marked increase in magnetic storage for information processing," added David Awschalom, a professor of physics and electrical engineering at the University of California, Santa Barbara.

Future storage devices might also be inspired by giant magnetoresistance, which relies on a property of electrons called spin.

Scientists are now exploring how to use spin to create new kinds of circuits and electronics, a field known as "spintronics."

"The increasing interest in semiconductor spintronics—our field—has partly also been inspired by the success of the GMR and its consequences," said physicist Manfred Ramsteiner of Paul Drude Institute in Berlin, Germany.

Fert and Grünberg will equally split the prize of 10 million Swedish kronor (about 1.5 million U.S. dollars).

Nobel Pursuits

Last year U.S. scientists John C. Mather and George F. Smoot won the Nobel Prize in Physics for research that helped solidify the big bang theory of the origin of the universe.

And yesterday three scientists— Mario R. Capecchi and Oliver Smithies of the United States and Sir Martin J. Evans of Britain—won the 2007 Nobel Prize in Physiology or Medicine for work on manipulating mouse genes to improve studies of genetic diseases.

The Nobel prizes have been awarded since 1901 based on the will of chemist and engineer Alfred Nobel, who invented dynamite.

The 2007 prizes in chemistry, literature, peace, and economics will be announced over the next two weeks.

The awards will be officially presented on December 10, the anniversary of Nobel's death.

"Missing" Moons, "Dirty" Ice Among Jupiter Flyby Finds

"Missing" moonlets, a huge volcanic eruption, and new maps of possible ocean ice are among the results of a recent flyby of Jupiter's moons.

The observations were made as NASA's New Horizons spacecraft whipped around the gas giant this past spring on its way to rendezvous with the dwarf planet Pluto in 2015.

Using Jupiter's gravity like a slingshot allowed New Horizons to shave years off its travel time to distant, icy Pluto.

The approach was also the first time a probe had been that close to Jupiter since the Galileo mission ended in September 2003.

Several teams of scientists used the opportunity to capture detailed images that allowed them to study different aspects of Jupiter.

Their findings appear in this week's issue of the journal Science.

No Tiny Moons

Perhaps the most surprising find for astronomers was an absence of tiny moonlets within the planet's rings.

Prior missions had revealed four small moons orbiting inside the orbit of the large moon Io.

The smallest of these are Adrastea, at 12 miles (20 kilometers) in diameter, and Metis, at 25 miles (40 kilometers) in diameter.

Earlier instruments weren't sensitive enough to spot moons much smaller than these. But scientists presumed that moonlets existed, because where there are big objects, there are usually lots of smaller ones.

"That's sort of how these things work," said Mark Showalter, a planetary scientist at the SETI Institute and lead author of a study on the "missing" moonlets.

Looking for moonlets is important, Showalter said, because they are thought to be the source of the dust that forms Jupiter's faint rings.

Such dust can be created when meteorites hit small moons within the rings, forming puffs of smokelike particles.

But despite the probe's ability to spot objects as small as 0.6 mile (a kilometer) in diameter, New Horizons found no new moons.

"It was really a surprise," Showalter said.

The most likely explanation, he continued, is that meteorite bombardment has battered such small bodies to the point that they are too small for New Horizons to detect.

But the new pictures did produce an unexpected find: clumps of debris within the planet's main ring.

While clumps of material aren't unusual, Jupiter's clumps were found in clusters that should have been rapidly dispersed by orbital forces.

"We haven't seen anything like this in any other planetary rings," Showalter said.

Lava and Frost

Other scientists examined three of Jupiter's larger moons—Io, Europa, and Ganymede.

Io is the most volcanically active body in the solar system.

During the flyby, a team led by John Spencer of the Southwest Research Institute in Boulder, Colorado, took a close look at the moon's giant Tvashtar volcano.

The massive mound happened to be undergoing a major eruption at the time of the flyby—as seen in an image released by NASA in May.

The volcanic plume was more than 215 miles (350 kilometers) high and 680 miles (1,100 kilometers) wide.

In their new study of the volcano images, Spencer and colleagues suggest that the plume's visible particles were not spewed from inside the moon but are instead gases that condensed in the frigid vacuum of space.

The team also notes that the magma inside Tvashtar and other Ionian volcanoes appear to be hot enough to be made of an Earthlike basaltic rock.

Another team, led by Kurt Retherford of the Southwest Research Institute, tried to determine what fraction of Io's atmosphere comes from volcanic emissions.

Io, Retherford said, has a very tenuous atmosphere made up of sulfur dioxide.

The scientists predicted that some of this gas comes from volcanism but that the rest comes from the evaporation of sulfur dioxide frost beneath the daytime sun.

The New Horizons flyby allowed the team to test this theory by studying Io's atmosphere when the moon passed out of the sun into Jupiter's shadow.

When there was no longer any solar heating, they found, 97 percent of the atmosphere quickly turned back into frost.

Ice Maps

When examining Europa and Ganymede, New Horizons scientists were primarily interested in mapping the distribution of "dirty" versus "clean" ice on the moons' surfaces.

The ultimate goal is to resolve a longstanding debate over the source of the material that contaminates the ice, particularly on Europa.

Europa is widely believed to have an ocean beneath its permanently frozen surface.

Scientists hope that the "dirty" ice is salt water that once welled up from below, which would provide proof of the undersurface ocean. But it could also be ice contaminated with sulfur compounds from nearby Io.

Studying the ice might offer clues to whether the underlying ocean is suitable for life, said William Grundy, a planetary scientist at the Lowell Observatory in Flagstaff, Arizona, who led the study.

The New Horizons instruments are sophisticated enough to tell what materials might be in the dirty ice, Grundy added, but at the time of the flyby the instruments hadn't been calibrated.

Once calibration is complete, he hopes to reanalyze the data to get a better answer.

Sex-Changing Chemicals Found in Potomac River

Ever since the discovery of gender-bending fish in the Potomac River, scientists have wondered what could be changing the sex of large numbers of fish in the waterway outside Washington, D.C.

They may not have to wonder much longer.

A recent U.S. government study has found large quantities of chemicals in the river and its tributaries—pollutants that are known to cause sex change in animals.

These chemicals, from both residential and industrial sources, may be linked to the unnatural fish, says the U.S. Geological Survey (USGS) report, which was released late last month.

Males With Eggs

The discovery of the abnormal fish "was largely accidental," said Douglas Chambers, a USGS scientist who led the study.

"In 2002 we were looking at stream-water chemistry to understand the large fish die-offs at these sites. It was then that we found smallmouth bass with intersex, a condition where male fish develop premature egg cells."

During a 2003 survey of the Potomac River and the Cacapon River of West Virginia, Chambers and his colleagues found large numbers of intersex fish.

The researchers also found chemicals from pesticides and flame retardants as well as fragrances commonly found in products such as soaps, antiperspirants, and deodorants.

"We analyzed blood plasma of 30 smallmouth bass from six sites," Chambers said. "All the fish contained at least one of the polluting chemicals, including fish that were not intersex."

However, Chambers said, the study has so far not turned up a single case of "imposex"—the condition in which female fish have malformed ovaries or produce sperm.

Once absorbed by the body, these chemicals—known as endocrine disruptors—interfere with normal bodily functions either by mimicking or blocking the production of hormones.

Experts say endocrine disruptors are found in pesticides, pharmaceuticals, fumigants, and fungicides. Municipal and domestic sewage and wastewater from farms and industries might be routing these chemicals into the water supply.

The presence of such chemicals is not unique to the Potomac. The pollutants have previously been documented in bodies of water in other parts of the United States as well as in Europe.

Scientists have also found reproductive problems in fish and birds in habitats along the U.S. Great Lakes. Similarly, declining alligator populations in Florida's Lake Apopka have been linked to synthetic chemicals that hinder reproduction.

Pollution Cocktail

Chambers says the USGS is analyzing data from last year and is planning to release a more detailed report later this year. The next report will try to make a definitive link between these chemicals and their effects on the environment.

"Currently many of these compounds have not been well researched for their environmental characteristics, how they are taken up by living organisms, and how they can be removed from streams," he added.

Dana Kolpin is a USGS research hydrologist and director of the agency's Emerging Contaminants Project. He reviewed Chambers' study but is not connected with it.

"This is the first step to understanding a very complex issue," Kolpin said.

"We need to understand the cocktail of compounds that are in the environment and whether there are certain bad actors that are causing feminization of males—and what it means for humans [who use this water]."

"It is critical to know where the sources are, how the compounds are being transported, and which ones are being degraded. What happens to them [after they enter the river] is the million-dollar question."

Coal Mining Causing Earthquakes, Study Says

The most damaging earthquake in Australia's history was caused by humans, new research says.

The magnitude-5.6 quake that struck Newcastle in New South Wales on December 28, 1989, killed 13 people, injured 160, and caused 3.5 billion U.S. dollars worth of damage.

That quake was triggered by changes in tectonic forces caused by 200 years of underground coal mining, according to a study by Christian D. Klose of Columbia University's Lamont-Doherty Earth Observatory in Palisades, New York.

The quake wasn't enormous, but Australia isn't generally considered to be seismically active and the city's buildings weren't designed to withstand a temblor of that magnitude, Klose said.

All told, he added, the monetary damage done by the earthquake exceeded the total value of the coal extracted in the area.

Klose presented his findings at a meeting of the American Geophysical Union in San Francisco, California, last month.

Heavy Burden

The removal of millions of tons of coal from the area caused much of the stress that triggered the Newcastle quake, Klose said.

But even more significant was groundwater pumping needed to keep the mines from flooding.

"For each ton of coal produced, 4.3 times more water was extracted," Klose said.

Other mining operations, he added, sometimes require as much as 150 tons of water to be removed for each ton of coal produced.

"So this is on the low end," he said.

Human-Caused Quakes

Coal mining isn't the only human activity that can trigger earthquakes.

Klose has identified more than 200 human-caused temblors, mostly in the past 60 years. "They were rare before World War II," he said.

Most were caused by mining, he said, but nearly a third came from reservoir construction.

Oil and gas production can also trigger earthquakes, he added.

Three of the biggest human-caused earthquakes of all time, he pointed out, occurred in Uzbekistan's Gazli natural gas field between 1976 and 1984

Each of the three had a magnitude greater than 6.8, and the largest had a magnitude of 7.3.

Human-triggered earthquakes are particularly dangerous, Klose said, if they occur in seismically inactive areas.

That's partly because people aren't prepared for them. But also, he said, "regions that are naturally inactive are very trigger-sensitive, because stress has built up over long periods of time."

Expensive Implications

Klose's presentation drew considerable attention from the assembled geophysicists, who wondered if there were ways to reduce the risk by altering mining practices.

"One way would be to find a way that doesn't reduce the water in the mine," Klose said.

But as far as he knows, mining engineers aren't examining this, because they are currently unaware of the earthquake risk.

The danger is also relevant to proposals to sequester carbon dioxide by injecting it into geologic formations deep underground where the gas cannot escape and contribute to global warming.

"That alters stress in the crust [too]," Klose said, adding that the risk of earthquakes should be taken into account in planning the locations of such facilities.

Basically, he said, "don't put the injection fields close to large cities."

The research could also have an impact on earthquake-insurance premiums, André Unger of the University of Waterloo, in Ontario, told National Geographic News by email.

The precise method by which premiums are calculated is a deeply guarded trade secret, but they appear to be based on a region's historical earthquake risk—"a purely statistical methodology," he said.

The new finding indicates that other factors are now at work, he said.

Furthermore, Unger noted that underground carbon sequestration might be a mixed blessing from insurance companies' points of view.

A carbon-sequestration plan could reduce the risk of some types of damage (such as from hurricanes, which some scientists say are being strengthened by global warming), while increasing the risk of others, like earthquakes.

Corals May Have Defense Against Global Warming

Ancient corals may have been more adaptable to changing ocean chemistry than previously thought, a new study shows.

The findings may offer hope that if the diversity of modern corals is preserved, they may be able to adapt as global warming causes seas to become more acidic.

These fossil corals in diverse reef communities adjusted to an acidic environment by altering the way they built their chalky skeletons.

Modern hard corals—known as scleractinians—form reefs of thousands of tiny skeletons made from a calcium carbonate called aragonite.

Aragonite is susceptible to the corrosive effects of acidic oceans, which today has become a byproduct of a build-up of carbon dioxide in the atmosphere.

"We now have many different arguments to prove that these corals were actually made originally out of calcite—and not just aragonite that was transformed after the coral died and become fossilized," said study co-author Jaroslaw Stolarski, a paleontologist from the Institute of Paleobiology at the Polish Academy of Sciences.

Curious Coral

The calcite skeletons were identified using several tests. Scientists inspected the microscopic structure of the skeleton and detected a high ratio of magnesium to calcium—a telltale fingerprint of calcite, not aragonite.

The fossil corals look like two-inch-long (five-centimeter-long) sea anemones nestled in porcelain egg cups. They belonged to the genus Coelosmilia, which existed during the Cretaceous period about 70 million years ago.

The Cretaceous oceans had a chemistry different than today, with much less of the metal ion magnesium and higher acidity.

"In the same environment there were coral neighbors, some with aragonitic skeletons, some with calcitic skeletons," Stolarski said.

"There was great biological variability among the corals, and some of them adjusted perfectly to the prevailing geochemical situation," he said.

Rachel Wood, a geologist from the University of Edinburgh, who was not involved in the study, said, "It begs the question: If having a calcite skeleton was so much better for life in such a corrosive sea, why aren't there more of them?"

The research will appear tomorrow in the journal Science.

Diversity Benefits

"This study has opened the door to the possibility that coral skeletons can potentially change back and forth from aragonite to calcite," said Stephen Cairns, research zoologist at the Smithsonian Institution's National Museum of Natural History in Washington, D.C.

"It suggests that animals and plants in general are quite adaptable creatures, and even though Earth changes—sometimes dramatically, like [in the case of] a comet hitting and wiping out 90 percent of animal life—it is so resilient that a vestige still gets through."

Co-author Stolarski said that diversity may be the key to adaptability, even in today's corals, which are under threat from warming seas.

"We should be extremely careful about coral reefs today, because they can only adapt to these changing environments if they maintain their diversity."

"If we completely eliminate some families or groups of corals, we may lose the very corals that would be able to adjust to changing environments in the future."

Cycad Plants "Woo" Insects With Heat, Odor

A primitive type of cycad plant from Australia relies on a surprisingly sophisticated system of meting out food to ensure successful pollination.

These plants take an active role in their reproduction by selectively attracting and repelling small insects known as thrips, a new study shows.

Scientists had long thought that cycads were passively wind-pollinated.

But in a push-pull system, male cones of this "living fossil" species heat up and emit strong odors to send pollen-bearing insects fleeing.

Female cones then emit a more attractive perfume to lure the bugs back in.

Pollination accomplished.

"I think the work demonstrates that plants aren't just sitting there looking pretty or just smelling good to attract their pollinators and that there's a lot more dynamics involved," said study co-author Irene Terry, a biologist at the University of Utah.

The mechanics of such primeval systems could provide insight into how pollination occurs in natural environments such as forests, something that Terry says there is still much to learn about.

The study appears this week in the journal Science and was funded in part by the National Geographic Society, which owns National Geographic News.

Nagging Mystery

Cycads are one ancient lineage of seed-producing plants called gymnosperms, which also include firs, spruce, pines, sequoias, and redwoods.

Found in tropical and subtropical areas, all species of cycads have separate male and female parts, often producing cones that look similar to a pinecone.

Tiny cracks between the tightly woven scales of the cones allow thrips to gain access to pollen in male cones and to structures containing eggs in female cones.

Both larval and adult thrips prefer the male cones, because the insects feed only on pollen.

But using some chemical tricks, the plants looked at in the new study ensure that thrips carry the male reproductive cells into the female cones.

"Twenty-five years ago when I began studying cycad pollination, it was still widely believed that cycads, like other gymnosperms, were wind-pollinated," said William Tang, an entomologist with the U.S. Department of Agriculture.

"Although I was involved in some of the early studies on cycad insect behavior, cone physiology, and odor analyses that supported the notion of insect pollination in this group, the precise details of this mutualism remained a nagging mystery," added Tang, who was not involved with the new study.

"This paper presents an elegant use of biochemistry, physiology, and field ecology to reveal the fine details of how this plant and its insect pollinator interact," he said.

"Through the use of heat and volatile chemicals, the plant choreographs a dance with its pollinators."

Stinky Males

Cycads have variable pollination periods, with reproduction occurring once a year to once every several years and lasting up to four weeks.

During that time, male cones use stockpiles of sugars and fats to heat themselves up, sometimes reaching 100 degrees Fahrenheit (38 degrees Celsius).

The cones also spew out huge doses of an odorous chemical called beta-myrcene.

"The odors get so strong that I don't want to be around them," study co-author Terry said.

"Some plants produce a stinky odor like a dead animal or poop, but this odor is just very harsh, hard to describe in terms of something similar."

Beta-myrcene attracts thrips at low concentrations, but in the amounts emitted by male cones, it becomes highly repellant, explained Robert A. Raguso, a chemical ecologist from Cornell University who was not involved in the study.

"This is a rather emphatic invitation for the thrips [to] leave home, and they do so bearing pollen," he said.

The plants do this "without dramatically changing their structural or visual characteristics, or even the chemistry of their scent," he added.

Tricky Females

Female cones emit much less beta-myrcene, so fleeing thrips searching for more pollen are drawn there.

When the thrips get inside the female cone, the ovule—containing the female reproductive cells—releases a little droplet, similar to a nectar droplet.

This draws the insects farther in. If they are carrying pollen, pollination is inevitable.

"The [study] highlights an elegant physiological mechanism by which cycads manipulate the behavior of thrips, transforming them from neutral or perhaps detrimental pollen predators to helpful pollinators," Raguso said.

Humans in Space in 2057

China's second manned spacecraft Shenzhou-6 sits abroad a Long March CZ-2F on the launch tower of the Jiuquan Satellite Launch Center in this undated photo released on October 11, 2005.

Fifty years after Russia's satellite Sputnik 1 launched an international space race, a new era of space exploration is now underway.

The governments of the United States, China, India, and Japan have announced high-profile plans to send humans back to the moon for the first time since 1972.

Chinese officials recently reiterated their intentions to use the Long March and Shenzhou craft to build a lunar outpost by 2020.

Zhang Qingwei, president of the China Aerospace and Technology Corporation, said that given the opportunity China would work jointly with the United States and other space powers to build a global settlement on the moon.

Birth of an Earthlike Planet Spied By Spitzer

A warm belt of dust around a young star is offering astronomers a glimpse of what Earth might have looked like when it was just beginning to take shape.

The star is part of a binary system known as HD 113766 that lies 424 light-years away.

Although it is slightly more massive than our sun, the star is only about 16 million years old—a baby compared to our 4.6-billion-year-old solar system.

And this young star seems to be in the early stages of forming its own rocky planets, a new study suggests.

The star system HD 113766 stands out clearly when looked at in infrared light, the part of the spectrum where dust shows up best.

Based on infrared data from NASA's Spitzer Space Telescope, astronomers say that the dust seems to be collected in a ring around the star within its "habitable zone," the region where water can stay liquid

Although the researchers can't see if any larger rocks have taken shape inside the dust, the abundance of material suggests that there's enough to form at least a Mars-size planet—or perhaps an Earth-size one.

"You've got all the right kinds of stuff—the age, the mass, the right location," said Carey Lisse of Johns Hopkins University in Maryland.

Lisse and colleagues will present their findings in an upcoming issue of the Astrophysical Journal.

Dust in Infrared

By examining the composition of the warm dust disk, Lisse's team was able to pinpoint what sort of body is most likely forming around the star.

A special instrument aboard Spitzer can search in the infrared spectrum for the fingerprints of particular molecules in the distant dust.

"We could actually tell what kind of dust is there" in the HD 113766 system, Lisse said. "In our case, it's rock and metal."

For example, the dust is rich in iron sulfides, a group of metals that includes the mineral pyrite, or fool's gold.

Lisse's team also noted what was not present in the dust: water ice and complex but fragile molecules known as hydrocarbons.

Thanks to the Deep Impact mission that analyzed the composition of Comet Tempel 1, the scientists knew that such materials would be expected if the dust was giving birth to comets.

And studies of meteorites that have made their way to Earth suggest that dust coming off of large asteroids should not have as much metal.

This means that the astronomers are seeing HD 113766 just as the predecessor of a rocky planet, known as a planetesimal, is forming.

What's more, a cooler disk farther out from the star appears to contain icy dust, a possible source of water for the newborn planet.

For now, the proto-planet is probably zooming around inside the dust disk, Lisse said. And we may be able to catch signs of the system as its planet grows up.

HD 113776 has been observed a few times, "and we know [the amount of dust] hasn't died down too much over 20 years," Lisse said.

"If it's at the end [of forming planets], there would be a lot of bumping and scraping, but we might actually see it dying down" in the near future.

"Or if it's young, it could flare up," showing occasional signs of more collisions between rocks, which would stir up more dust.

"Stay tuned," Lisse added. "I expect lots more fireworks as the planet in HD113766 grows."

Star "Jewel Box" Spotted by Hubble

This diamond-sharp Hubble Space Telescope image of some of the Milky Way's biggest stars shows a stellar nursery surrounded by a vast region of dust and gas.

Inside the NGC 3603 nebula, the stars run the gamut in age and mass—allowing scientists to analyze stars in different stages of their life cycles.

Released today, the new image suggests NGC 3603, which is about 20,000 light-years away, gathers its biggest stars at its core. It also shows that the nebula's dense distribution of stars mirrors other young clusters in the Milky Way, Jesús Maíz Apellániz, leader of the Hubble investigation, said in a statement.

The brightest stars in the image appear blue. Ultraviolet radiation and violent winds from these stars have created a large cavity in the reddish debris enveloping the cluster.

The nebula, discovered by Sir John Herschel in 1834, contains about 400,000 solar masses of gas.

A few Bok globules—dark clouds of dense dust and gas that are 10 to 50 times larger than the sun—also lurk in NGC 3603's swirling mass (visible as tiny black splotches at top right).

The globules are some of the coldest objects in the universe.

Saber-Toothed Cat Had Weak Bite, Digital Model Says

Despite its fearsome fangs, the saber-toothed cat Smilodon fatalis may have been a relatively wimpy biter—at least compared to modern-day lions.

The prehistoric cat with the 6.5-inch (17-centimeter) chompers roamed the Americas as recently as 10,000 years ago, preying on bison, horse, and possibly even woolly mammoths.

Now computer modeling has revealed that the cat's jaws could apply only about 220 pounds (100 kilograms) of pressure, said Colin McHenry, a doctoral student at the University of Newcastle in Australia.

That's just a third of the bite strength of a lion, which can exert up to 660 pounds (300 kilograms) of force with its jaws.

The find offers new clues to understanding the hunting style of the ancient predator.

Lions, for example, can bring down their prey by leaping on them and biting their necks.

"But that would put an enormous amount of stress on the [saber-tooth's] skull," McHenry said. "So we think it had to tackle its prey before biting."

Based on the Ice Age cat's body shape, this isn't actually surprising, he added.

"People think of [the saber-toothed cat] as a lion with big teeth. But if you'd actually seen it, you'd have thought it was a bear with big teeth. [It was] built for wrestling large prey to the ground."

McHenry and colleagues at the University of Newcastle and the University of New South Wales publish their findings this week in the Proceedings of the National Academy of Sciences.

Saber-Tooth Crash Test

McHenry's team used a method called finite element analysis to simulate the stresses that would have been placed on the saber-toothed cat's skull while biting its prey.

Finite element analysis is a modeling technique developed by engineers for evaluating stresses on mechanical objects such as airplanes.

"You can think of it as a way of digital crash testing," McHenry said.
The test showed just how much pressure the saber-tooth's jaws could create before breaking the skull.

The computer model also helped reveal what the cat might have done once it had its prey down on the ground.

Paleontologists have long wondered whether the saber-toothed cat used its signature teeth to attack an animal's belly or neck.

One argument was that the cats used their fangs to eviscerate their prey, tearing into an animal's soft underside.

But attempting to hold a still-living buffalo down while biting its belly would allow the prey to thrash around enough to put dangerous pressure on the saber-tooth's jaw.

Cowboys, however, have long known that they can hold animals like buffalo down by their heads with relative ease.

And this, McHenry said, was probably what the saber-tooth did—using its long fangs to bite its prey's neck.

Modern lions actually hold prey down in a similar way. But once its prey is secure, the lion kills it with strong jaws designed to crush and suffocate.

With its weaker jaws, the saber-toothed cat couldn't suffocate its prey. Instead its long teeth would have pierced the animal's windpipe and carotid artery—killing it fairly quickly.

This might have actually been an advantage for the saber-tooth, since it can take a lion up to ten minutes to kill a buffalo by strangulation.

"That's a lot of time," McHenry said, noting that the saber-tooth had to compete with other big Ice Age predators hoping to steal its kill.

"The advantage of a quick kill seems to be quite significant."

Other scientists agree that computer modeling provides a good way of testing hypotheses about the behavior of extinct animals.

"It's important," said Mark Goodwin, a vertebrate paleontologist and assistant director of the University of California Museum of Paleontology.

Similar studies have been done with dinosaurs, he noted, such as one study that examined the cranial strength—and thus the feeding habits—of the Tyrannosaurus rex.

Bears, Winds Fail to Derail 1st Winter Arctic Foot Trek

The first ever winter trek to the North Pole reached its goal today despite setbacks from weather, equipment failures, and polar bears.

"It's great to finally be standing on the North Pole," South African explorer Mike Horn wrote on his expedition Web site. "This mystical place is all that it is made out to be. It's incredible out here!!"
Horn and Norwegian explorer Børge Ousland conceived the trip because they wanted to see sunrise from the North Pole. And to get there, they wanted to trek overland—or more specifically, over ice.

Although dawn has illuminated the region with pastel light for at least a couple of weeks, official Arctic sunrise happens only once a year: on the vernal equinox, when the sun crosses the equator.

That means that Ousland and Horn had to do something nobody else had ever attempted: ski, drag sleds, and occasionally swim through the heart of the Arctic winter.

Atrocious weather held them back, but they still managed to reach their goal this afternoon 60 days and 5 hours after setting off.

"This is a fantastic thing—a first," said photographer Kjell Ove Storvik.

Storvik, a personal friend of Ousland's, watched the pair's departure on January 22 and then tracked their progress via satellite-phone conversations.

Thinking Like Polar Bears

Winter travel in the far north poses a host of problems not encountered by prior expeditions.

To the uninitiated, the worst of these might seem to be the cold. And that has indeed been an enemy, dropping the mercury as far as -40°F (-40°C) and frostbiting Horn's fingertips.

But the extreme cold is also a friend, because it freezes the ice more solidly and reduces the number of open-water gaps, or leads, between ice floes that the travelers had to navigate.

To cross these leads Ousland and Horn used a bold but simple method: swimming.

After all, Ousland reasoned when he came up with the idea, that's how polar bears get across.

When they came to open water, the adventurers donned insulated drysuits and swam across stretches as wide as an eighth of a mile (about 200 meters).

In the water the trekkers towed their equipment sleds behind them, or when necessary, pushed a sled in front to break through thin skins of ice.

Once across they took another hint from polar bears and rolled in the snow to dry the moisture off their suits before taking them off and packing them away.

Loss of Perspective

But leads weren't the only problem: Until approaching spring brought endless dawn, the pair also had to contend with darkness that ate their headlamp beams and made it difficult to figure out the best way around obstacles.

That forced them to use a tactic Horn developed during a previous trek through the trackless Amazon jungle.

If you can't see well enough to pick the best route, go as close as possible to straight ahead and bull through whatever lies in your way.

Traveling in the dark is worse than simply not being able to see where you're going, said Gary Dunkley, a mountaineer, arctic traveler, and spelunker.

The explorer once spent 12 consecutive days underground on a National Geographic Expedition in Belize.

When you're working by headlamp, he said, there's no light directly beneath your feet. That forces you to remember what you're about to step on.

The straight-ahead illumination of the headlamp also appears to "flatten" the landscape, robbing you of perspective and making it hard to recognize bumps and dips.

Ousland and Horn traveled on skis, which made it a bit easier not to trip over things, but the same problems still applied.

"Sometimes we feel that we're skiing to the North Pole inside a tunnel," Ousland wrote in the expedition's blog.

Moving Backward

Wind is also an obstacle, because it not only increases the risk of frostbite, it causes the ice to move.

"You can drift [backward] five kilometers [about three miles] at 'night' while sleeping, then have to walk that five kilometers again in the morning," Storvik said.

"Their first month was an endless story of walking and drifting back."

Wind also delayed the expedition's start from Siberia's Cape Arktichesky by nearly two weeks. Strong gusts blew the pack ice out to sea, creating an uncrossable expanse of open water between the shore and the ice.

During that time Ousland and Horn's camp was twice raided by polar bears, including one that attempted to break into their tent while they were sleeping.

Luckily, they were able to scare the bear away with a flare gun.

From then on the delays continued to mount: frigid headwinds, Horn's frostbite, broken tent poles, broken skis, and ultimately a mysterious illness that robbed Horn of much of his energy.

But conditions improved and the expedition got back on track to reach the pole today—its initial target date.

As of yesterday the trekkers were a mere 13 miles (21 kilometers) shy of their goal.

"I am really looking forward to finishing this journey while enjoying the light of the midnight sun," Ousland wrote in his blog.

In addition to their record-breaking voyage, Storvik says, Ousland and Horn's journey represents the triumph of two explorers from different cultures who are each accustomed to working alone.

"Everyone doomed them in the beginning," Storvik said. "But it turns out they've become really good friends."

And the triumph of that "human factor," he says, is at least as important as the completion of their expedition.

Birds Can "See" Earth's Magnetic Field

To find north, humans look to a compass. But birds may just need to open their eyes, a new study says.

Scientists already suspected birds' eyes contain molecules that are thought to sense Earth's magnetic field. In a new study, German researchers found that these molecules are linked to an area of the brain known to process visual information.

In that sense, "birds may see the magnetic field," said study lead author Dominik Heyers, a biologist at the University of Oldenburg.

Magnetic Orientation

Human-made compasses work by using Earth as an enormous magnet and orienting a tiny magnet attached to a needle to the planet's north and south poles.

Scientists have thought for years that migratory birds may use an internal compass to navigate between their nesting areas and wintering grounds, which can be separated by thousands of miles.

The new research helps explain how this natural compass may work.

Heyers and his colleagues injected migratory garden warblers with a special dye that can be traced as it travels along nerve fibers.

The team put one type of tracer dye into the eyes and another in a region of the brain called Cluster N, which is most active when birds orient themselves.

When the birds got their bearings, both tracers traveled to and met in the thalamus, a region in the middle of the brain responsible for vision.

"That shows there is direct linkage between the eye and Cluster N," Heyers said.

The finding strongly supports the hypothesis that migratory birds use their visual system to navigate using the magnetic field.

"The magnetic field or magnetic direction may be perceived as a dark or light spot which lies upon the normal visual field of the bird," Heyers said, "and which, of course, changes when the bird turns its head."

The study was published in a recent issue of the Public Library of Science journal PLoS ONE.

More Navigational Tools

Scientists not involved with the study said it is impressive and well done, but cautioned that there are more pieces to the puzzle of how birds navigate on their long migrations.

"An animal that has to migrate over great distances needs to have both a compass and a map," said Cordula Mora, a biologist who recently completed her postdoctoral research at the University of North Carolina, Chapel Hill.

Mora's work suggests that birds may use magnetic crystals in their beaks to sense the intensity of the magnetic field and thus glean information on their physical location.

"If you have a compass, you know where north, south, east, [and] west [are], but you don't know where you are, so you don't know where you should be going," she said.

Study author Heyers said "both [map and compass] systems may act in concert."

Robert Beason is a wildlife research biologist with the U.S. Department of Agriculture in Sandusky, Ohio, and an expert on bird navigation.

He noted that stars may also either fully or in part provide the birds with their visual bearing—not the magnetic field.

The next step is to figure out where all this information comes together in the bird brain, he noted.

"That's probably going to tell us where the navigation center for birds is," he said.

"Ugly" Albino Ratfish Captured

This ghostly animal is a completely different kettle of fish.

The albino white-spotted ratfish caught this summer during a marine survey in Washington's Puget Sound is the first albino fish ever spotted by local scientists.

Ratfish, bottom-dwelling relatives of skates and stingrays, are usually brown with white spots that act as camouflage.

The fish probably owe their name to their exceptionally long tails and rodentlike teeth that crush up clams and other prey lurking in the mud.

"They're pretty ugly," John Reum, the University of Washington doctoral student who caught the fish, told the Associated Press news agency.

The foot-long (30-centimeter-long) pearly white female seen here had pale green eyes and was estimated to be about two or three years old—just an adolescent.

"This animal would stand out like a beacon," fisheries professor Ted Pietsch told the AP. "I don't know why it wasn't eaten long before."

But the rare creature's luck ran out—it died shortly after capture.

It now sparkles as the only albino specimen in the university's collection of 7.2 million fish.

New Artificial Reefs "Grow" From Mideast Peace Deal

In a rare example of Middle East cooperation, Israelis and Jordanians have joined together to create a string of artificial coral reefs in the Red Sea.

The international effort is meant to attract divers and snorkelers to artificial reefs to allow the area's damaged natural reefs to heal.

A high diversity of corals thrive in the Gulf of Aqaba, which lies at the northern end of the Red Sea and is bordered by both Israel and Jordan as well as Egypt and Saudia Arabia farther south.

These reefs draw tourists from around the world to the neighboring resort cities of Elat, Israel, and Al 'Aqabah, Jordan.

The tourism dollars are a boon to the region's economy, but an onslaught of snorkelers and divers has taken a damaging toll. Many of the reefs are literally dying, experts say.

Reefs on Jordan's coast, though still at risk, have so far suffered less from human pressures than those on the more heavily visited Israeli and Egyptian coast.

"There is increasing construction, industrial development, and tourism around the gulf. Elat and [Al ']Aqabah are fast-growing cities and pressure on the reefs is growing," said Fuad Al Horani of the Marine Science Station (MSS) in Al 'Aqabah.

MSS and a team from the Elat campus of Ben-Gurion University (BGU) are spearheading the reef construction.

A 1994 peace deal between Israel and Jordan mandated that the two countries work together on combating marine pollution, natural resources issues, and coastal reef protection in the gulf.

Researchers are also gathering critical data on these complex ecosystems, including coral survival rates and patterns as well as the effects of human behavior on reefs.

Reviving the Reef

Using cranes and large parachutes, the team has already sunk huge concrete structures, each weighing 4.2 tons, into water 19 to 22 feet (6 to 7 meters) deep. Before installation, corals were nursed in special tubes designed to fit in holes drilled into the artificial reef.

In September researchers aided by university students and Israeli schoolchildren glued the tubes across the surfaces of the irregularly shaped modular building blocks.

About 250 of the coral-filled tubes have already been planted on the reef, and more are in the works.

Inner areas of the new human-made reef are barred to prevent the entry of divers and encourage new coral growth and colonization by fish and other marine life.

"Usually when something bad happens to a protected marine area, you can only say, Okay, we lost a part of it," said Nadav Shashar, BGU's marine biologist and project supervisor.

"But here we are actually able to reclaim an area. This used to be a coral reef and it died. But now we can go back and build a new one."

Just two months after initial construction, more than 20 species of fish—along with invertebrates including corals, fan worms, and tunicates—have settled naturally on the reef.

Shashar anticipates the artificial structure will need between five and ten years to evolve into a viable reef ecosystem.

But fish populations will likely fully colonize the project within a year.

When completed, the project will include three reefs in Jordanian waters and two in Israel. But it is not intended to replace natural ecosystems.

Instead, the new reefs provide alternate dive areas and help in the reclamation of specific reefs.

Artificial vs. Natural

There are biological differences between natural and artificial reefs.

Natural reefs contain tiny ecosystems that are dependent on light and nutrients as well as sea current strengths and speeds, Al Horani of Jordan's MSS said.

Artificial reefs do not necessarily provide the physical infrastructures for these micro-ecosystems.

"We are trying to create different types of micro-ecosystems within the structures we are developing," Al Horani said. For instance, some surfaces are exposed to full sunlight, and others are more shaded.

Shashar of Israel's BGU intentionally designed the new reef in a way that does not mimic a natural reef, but rather provides an alternate habitat for rare species.

Similar Pressures

Natural reefs in the U.S.—including the Florida Keys and Hawaii—and the Bahamas are also facing dangerous pressures similar to those of the Gulf of Aqaba reefs.

Bob Leeworthy of the National Oceanic and Atmospheric Administration was not involved in the Gulf of Aqaba project.

He has worked on a Florida Keys artificial reef study that involved the intentional sinking of a decommissioned U.S. naval vessel.

Such projects can help save natural reefs by taking stress off them, he said.

"It was a win-win situation in the sense that total use—including scuba diving, snorkeling, glass-bottom boat rides, and fishing—increased while the use of the surrounding natural reefs declined," Leeworthy said.

Advertising the artificial reef site led to a direct increase in business traffic at local scuba outfitters, he added. Anecdotal information suggests that visitor interest in the artificial site remains steady today.

Both MSS's Al Horani and BGU's Shashar said relations between the Israeli and Jordanian team members are positive.

"We have common goals," Al Horani said.

"Without this kind of collaboration we can't really control the environmental factors that might negatively influence the Gulf of Aqaba."

Lethal Bacteria Turn Deadlier After Space Travel

Bacteria can change into more infectious and deadly organisms after a stint in space, a new experiment suggests.

A science experiment on board space shuttle Atlantis in 2006 included Salmonella typhimurium bacteria, which is often fatal in humans.

When the bacteria—which had been safely isolated from the space crew—returned to Earth, scientists injected them into mice.

They found the space-faring bacteria caused death quicker and more often than Earth-restricted organisms.

The findings are concerning for future astronauts who will embark on longer space missions farther away from Earth-based medical help, experts say.

Genetic Transformations

Cheryl Nickerson is an associate professor of microbiology at Arizona State University's Biodesign Institute and lead author of the study.

Nickerson wanted to see if space's low-gravity environment would affect Salmonella. Usually a culprit in food poisoning, the bacteria can cause vomiting, fever, diarrhea, and abdominal cramps. Most types of Salmonella, which can grow on most foods, are fatal in the elderly or young if left untreated.

When the bacteria returned to Earth, genetic sequencing showed that 167 genes and 73 proteins had been altered.

One protein, called Hfq, helped control more than a third of the altered genes. Hfq regulates RNA—the code of bacterial life—during stressful events. When activated, the protein previously had been shown to strengthen several types of pathogens.

An technique called scanning electron microscopy also showed some Salmonella were starting to form biofilms, a protective slime layer.

On Earth, biofilms can grow on ship hulls and clog pipes, costing industry billions of dollars. Biofilms also worsen some diseases and reduce the effectiveness of many antibiotics.
Nickerson and colleagues, whose study appears online in today's Proceedings of the National Academies of Sciences, have tested bacteria in a variety of harsh environments.

"In the last few decades, huge leaps of knowledge have been made when we test biology in extremes," she said.

"Situations where it is very hot, very acidic, or low oxygen have taught us an enormous amount about how cells respond to those environments, and from that we've made huge advances in biotech and bioengineering."

All About the Fluids

It's not lower gravity that makes bacteria deadlier in space.

The key environmental change is a mechanical force known as fluid shear, or the motion of fluid around a cell.

In human gastrointestinal tracts, this current slows down or even stops, creating an area of low fluid shear. These environments allow bacterial infections to flourish. Space is also a low-shear environment.

"Fluid shear ... is an environmental signal that had been overlooked for quite a while," Nickerson said.

That's because ground-based techniques can't replicate accurate fluid shear environments.

But in space, scientists can control fluid shear far better than in any Earth-based lab.

Deep Impact

By understanding the role of fluid shear on the evolution of disease-causing bacteria, scientists hope to offer better techniques to fight disease on Earth.

David Niesel, chair of microbiology and immunology at the University of Texas at Galveston, was not involved in the study.

"[The study] is a nice piece of work. It shows an increase in virulence in an animal model and a molecular mechanism that could account for that," he said.

"Anything we learn about how bacteria respond to new environments and their virulence mechanisms may help us understand how these organisms cause disease, and that gives us new opportunities to come up with therapeutics to combat disease on Earth."

Understanding how bacteria alter themselves in space will be especially important for future long-term missions, such as colonization of the Moon or a manned mission to Mars.

"What happens in microgravity at the cellular level is not really well understood," said Steve Maclean, a Canadian astronaut and crew member on the 2006 Atlantis shuttle that housed the experiment.

Since bacteria are always present inside humans, it is impossible to prevent any of the organisms from getting into the space shuttle.

"Given that bacteria survive better and our immune system is functioning at a lower level, does this increase your risk of infection?" Maclean said.

"It's something to think about before we go to Mars."

Dolphin "Chat Line" to Help Deaf Mom's Calf "Talk"

An underwater "chat line" may help stimulate communication development in an unborn dolphin—in ways the calf's mother, which is deaf, cannot.

Castaway, a pregnant Atlantic bottlenose dolphin, has been living at the Marine Mammal Conservancy (MMC) in Key Largo, Florida, since January, when she was found stranded in Vero Beach.

A battery of tests determined that the mother-to-be is profoundly deaf. Deafness can be fatal for dolphins in the wild. The animals rely on echolocation—the sending and receiving of sound waves—to socialize, find prey, and avoid predators.

"Dolphins live in a world of sound," said MMC president Robert Lingenfelser. "The inability to hear makes them blind, in a sense."

Scientists do not know what caused Castaway's deafness, but they doubt that the dolphin has been deaf since birth.

The bottlenose is about 27 years old. Researchers believe it is highly unlikely that she would have survived so long in the wild, even with help from her pod, if the dolphin had been deaf its entire life.

Concerns for Calf

Castaway's deafness could also hinder her ability to teach her calf vital developmental skills.

The first few months of life are the most critical for newborn dolphins to learn survival skills, Lingenfelser says.

To date, Castaway has only uttered a few sounds in a low-frequency monotone—a stark contrast to an average dolphin's steady stream of high-frequency chirps, squeaks, and clicks.

"Probably our biggest concern is that the calf will not develop the ability to communicate if the mother is not communicating," said Jill Borger-Richardson, director of research and education at Dolphins Plus, a Key Largo dolphin and marine mammal research and education facility.

Dolphins Plus scientists have consequently recorded several "conversations" of their hearing dolphins. Those recordings are now being played in Castaway's pen via underwater speakers to promote the fetal calf's communication development.

Underwater Chat Line

Once the calf is born, scientists plan to turn off the stereo and give Castaway the opportunity to communicate with her calf on her own.

If Castaway's verbal repertoire does not improve, staff will try opening up a live chat line between the dolphins at MMC and those at Dolphins Plus. Even then, success is not guaranteed.

"At the very least, [these efforts] might help the calf assimilate into its pod when it's moved to a new facility," Borger-Richardson said. "If it's not going to hurt them, we might as well give it a try."

Castaway has a mid-May due date. MMC scientists will monitor the bottlenose and her newborn calf for at least nine months before transporting the pair to another facility.

Given Castaway's deafness and her calf's potential developmental delays, neither dolphin will be released into the wild.

The World Map Master Baby Genius

'Lunar Ark' Proposed in Case of Deadly Impact on Earth

The moon should be developed as a sanctuary for civilization in case of a cataclysmic cosmic impact, according to an international team of experts.

NASA already has blueprints to create a permanent lunar outpost by the 2020s

But that plan should be expanded to include a way to preserve humanity's learning, culture, and technology if Earth is hit by a doomsday asteroid or comet, said Jim Burke of International Space University (ISU) in France.

Burke, once a project manager on some of the earliest American lunar landings, now heads an ISU study on surviving a collision with a near-Earth object.

An impact of the size that wiped out the dinosaurs hasn't happened since long before the rise of humans, he pointed out.

Yet scientists' expanding knowledge of asteroids and craters left throughout the solar system has created a consensus that Earth remains vulnerable to a civilization-crushing collision.

This calls for the creation of a space age Noah's ark, Burke said.

Lunar Ark

Humans are just beginning to send trinkets of technology and culture into space. NASA's recently launched Phoenix Mars Lander, for example, carries a mini-disc inscribed with stories, art, and music about Mars.

The Phoenix lander is a "precursor mission" in a decades-long project to transplant the essentials of humanity onto the moon and eventually Mars.

The International Space University team is now on a more ambitious mission: to start building a "lunar biological and historical archive," initially through robotic landings on the moon.

Laying the foundation for "rebuilding the terrestrial Internet, plus an Earth-moon extension of it, should be a priority," Burke said.

The founders of the group Alliance to Rescue Civilization (ARC) agreed that extending the Internet from the Earth to the moon could help avert a technological dark age following "nuclear war, acts of terrorism, plague, or asteroid collisions."

But the group also advocates creating a moon-based repository of Earth's life, complete with human-staffed facilities to "preserve backups of scientific and cultural achievements and of the species important to our civilization," said ARC's Robert Shapiro, a biochemist at New York University.

"In the event of a global catastrophe, the ARC facilities will be prepared to reintroduce lost technology, art, history, crops, livestock, and, if necessary, even human beings to the Earth," Shapiro said.

ARC hopes to finance the planned moon outpost into a lunar ark of recovery in part through donations from billionaire philanthropists.

"The establishment of an ARC sanctuary would for the first time provide a compelling purpose for the colonization of space."

If the international lunar outpost of the 2020s expands into a colony and then a city, "it is possible that a whole new phase in civilization may develop—the branching of history into one stream on Earth and another on the moon," ISU's Burke added.

This "dual-world expansion" could be within reach by the end of this century, he said.

"Look at the last century, when we went from the Wright brothers to the Apollo missions—along with man's great expansion of his understanding of the cosmos."

Plan B?

Kilian Engel, an instructor at the International Space University who is involved in post-doomsday research, said the lunar archive is actually Plan B.

"Plan A involves creating an international network of astronomers to scan space for asteroids and comets that might threaten Earth, a global task force to formulate a strategy to prevent impacts with the planet, and a new generation of spacecraft to carry out these missions," Engel said.

More awareness of the danger posed by asteroids and comets is now spreading across the United States and the world.

In 2005 Congress directed NASA to figure out how to survey space for threatening near-Earth objects, as well as how to develop spacecraft to deflect or shoot them out of space.

Yet NASA receives less than five million U.S. dollars per year to conduct this "Spaceguard Survey," which is aimed at finding near-Earth objects greater than 0.62 mile (a kilometer) in diameter.

NASA has reviewed options that range from building titanic space tugboats to nudge asteroids off a collision course with Earth to crashing "kinectic impactors" into an oncoming comet.

Nuke Option

In March 2007 researchers at NASA's Near-Earth Object Program released a report that said nuclear explosions are ten to a hundred times more effective in diverting killer asteroids than non-nuclear alternatives.

Even so, "30 to 80 percent of potentially hazardous near-Earth objects are in orbits that are beyond the capability of current or planned launch systems," the report said.

And even if NASA eventually develops a nuclear-tipped, anti-asteroid launch vehicle, rocketing hydrogen bombs into space "is prohibited by the Outer Space Treaty of 1967," ISU's Burke said.

That UN-brokered treaty prohibits the deployment of nuclear weapons in Earth orbit, in outer space, or on any other celestial body.

Yet as astronomers across the globe piece together predictions on potential asteroids of mass destruction, UN members could vote to amend the space treaty to prepare a nuclear response to such threats.

Giant Bugs a Thing of the Past, Study Suggests

For the giant insects that roamed Earth 300 million years ago, there was something special in the air.

A higher concentration of oxygen in the atmosphere let dragonflies sometimes grow to the size of hawks, and some millipede-like bugs reached some six feet (two meters) in length, a new study suggests.

Now that the proportion of oxygen has decreased, however, bugs can't grow much larger than they do now, the authors write.

The reason: The bigger an insect, the bigger the proportion of its body devoted to its tracheal system, which functions like a lung but is far less efficient at large sizes.

"[The tracheal system] explains why they are small," said study co-author Jon Harrison, a professor of environmental physiology at Arizona State University. "It takes up all the room."

The study appears this week in the journal Proceedings of the National Academy of Sciences.

Bigger Bodies, Bigger Lungs

Scientists have long puzzled over why bugs once grew to gigantic proportions but are now among Earth's more diminutive creatures.

"There were hundreds of ideas to explain the small size, but none of them could be proven," said lead study author Alexander Kaiser, of Midwestern University's Department of Basic Sciences.

So Kaiser and colleagues decided to test the idea that it was it was an insect's respiratory system that limited its size by studying beetles and fruit flies.

The team looked at beetles by peering through their exoskeletons with new x-ray beam technology at Argonne National Laboratory in Illinois.

This allowed the scientists to see how much room was dedicated to the respiratory system among four species of darkling beetles ranging from 0.1 to 1.3 inches (3.2 to 33 millimeters) in length.

Insects carry oxygen to cells differently from humans. Instead of a single breathing tube, bugs have several pairs of holes known as spiracles along their bodies.

These holes connect to tubes called tracheae, which transport oxygen to cells and remove carbon dioxide.

The x-ray scans revealed that as beetles become larger, tracheae take up proportionally more room in their bodies because they need to be longer and wider to deliver enough oxygen. This, in turn, inhibits growth by crowding other organs.

The tracheae in the larger beetles took up 20 percent more room than in smaller beetles.

The area where the body and legs meet is particularly limiting, because that opening can only get so big, Harrison noted.

In the smallest beetle, tracheae take up 2 percent of the region, compared with 18 percent in the largest.

Using that information, Harrison estimated that the maximum beetle size under current oxygen levels would be about six inches (15 centimeters).

That coincides roughly with the largest known living beetle, the Titanic longhorn.

"This paper is really interesting in part because there is still a lot we don't know about how insects breathe," said Scott Kirkton, an assistant professor of biology at Union College in Schenectady, New York, who was not associated with the study.

Something in the Air

During the late Carboniferous period (354 to 290 million years ago), however, oxygen levels were much higher than they are now, partly because coal swamps that leaked the gas into the air were very common.

"Back then, there was 31 to 35 percent oxygen in the air," study lead author Kaiser said. "Now we have about 21 percent."

That meant insects needed smaller quantities of air to meet their oxygen demands, allowing the creatures to grow much larger.

"The tracheal diameter can be narrower and still deliver enough oxygen for a much larger insect," Kaiser said.

The team, though, is still trying to definitely show that this phenomenon explains why Carboniferous insects were so large.

Neither fruit flies nor beetles were around, or even had close relatives, during the Carboniferous, so the team hopes to extend its research to more ancient insects such as dragonflies, Kaiser said.

The scientists have already experimented with fruit flies in a lab at Arizona State, raising them in tanks with different levels of oxygen.

Under higher concentrations of oxygen the fruit flies definitely get bigger, Harrison said.

Life-Forms "Resurrected" After Millennia in Ice

Imagine sticking some bacteria in the freezer and taking them out millions of years later to find that they are still alive.

That would be similar to what happened recently, when scientists brought eight-million-year-old microbes back to life—simply by thawing them.

The ancient bacteria were found frozen in the world's oldest known tracts of ice, the debris-covered glaciers of Antarctica.

"We think that they were pretty much locked in a frozen, inanimate state for that period of time," said lead study author Kay Bidle, a marine microbiologist at Rutgers University in New Brunswick, New Jersey.

It's also possible that some of the microbes were capable of maintaining their metabolism within tiny droplets of water suspended in the ice, Bidle said.

Bidle and colleagues retrieved and revived two samples of bacteria from the glacial ice. The first was a hundred thousand years old, and the second was around eight million years old.

The eight-million-year-old bacteria were alive, but barely.

Their genes were severely damaged from long exposure to cosmic radiation, which is higher at Earth's poles.

The radiation bombarded the bacteria's DNA with high-energy particles, which broke apart the DNA's chemical bonds and hacked it into shorter pieces.

Big Bacterial Thaw

Most of the bacteria in the samples probably blew over from African deserts, said study co-author Paul Falkowski, a biochemist at Rutgers.

Once the bacteria landed on the glacier's snowy surface, they were compressed with the snow to form ice.

"These ices are literally gene banks," he added.

That's because bacteria are able to incorporate foreign DNA into their own genetic makeup in a process called horizontal gene transfer.

This gives bacteria a way to pick up new advantageous traits, which in turn speeds up their evolution.

Falkowski likens the Antarctic ice to a "genetic popsicle."

As glaciers and ice caps melt as a result of the current trend of global warming, vast amounts of bacterial genetic material might be flushed into the ocean.

"You basically have this mechanism by which you're freeing up encased DNA and microbes that may be viable," lead author Bidle said.

Scraps of bacterial DNA might get incorporated into today's marine microbes, or viable bacteria released from the ice might also grow and impact the ecosystem.

"How that's going to play out, we don't know," Bidle said. He and Falkowski plan to focus future work on how current ice melting impacts modern microbes' genetic diversity.

The study appears in this week's journal Proceedings of the National Academy of Sciences.

Meaning for Mars?
The finding also lends hope to the possibility that microbes could lie in a similar suspended state in ancient Martian ice.

But it also nixes the idea that life could hitch a ride on comets between solar systems.

"Each solar system is an island of life," Falkowski said. Microbes on comets would be exposed to lethal doses of cosmic radiation for millions of years during their journey, he said.

"Under those conditions you would be sterilizing comets."