Georg Kaser, a glaciologist at the University of Innsbruck, Austria, who led the research, said: "The glaciers are going to melt and melt until they are all gone. There are not any glaciers getting bigger any more."

Loss of land-based ice is one of the clearest signals of global temperature rise, and the state of glaciers has become a key argument in the debate over climate change. Last year, New Scientist magazine published a letter from the television botanist David Bellamy, a renowned climate sceptic, which claimed that 555 of 625 glaciers measured by the World Glacier Monitoring Service have been growing since 1980. His claim was quickly discredited, but the perception that glaciers are both growing and shrinking remains.

Dr Kaser said that "99.99% of all glaciers" were now shrinking. Increased winter snowfall meant that a few, most notably in New Zealand and Norway, got bigger during the 1990s, he said, but a succession of very warm summers since then had reversed the trend. His team combined different sets of measurements which used stakes and holes drilled into the ice to record the change in mass of more than 300 glaciers since the 1940s. They extrapolated these results to cover thousands of smaller and remote glaciers not directly surveyed.

The results revealed that the world's glaciers and ice caps - defined as all land-based ice except the mighty Greenland and West Antarctic ice sheets - began to shrink far more quickly in 2001. On average, the world's glaciers and ice caps lost enough water between 1961 and 1990 to raise global sea levels by 0.35-0.4 mm each year. For 2001-2004, the figure rose to 0.8-1mm each year.

Writing in the journal Geophysical Research Letters, the scientists say: "Late 20th century glacier wastage is essentially a response to post-1970 global warming." Dr Kaser said: "There is very, very strong evidence that this is down to human-caused changes in the atmosphere."

Emissions of greenhouse gases such as carbon dioxide trap heat in the atmosphere, warming the surface. One of the first impacts of glacier melting is likely to be in South America. In August, a report from 20 UK-based environment and development groups warned that Andean glaciers are melting so fast that some are expected to disappear within 15-25 years.

This would deny major cities water supplies and put populations and food supplies at risk in Colombia, Peru, Chile, Venezuela, Ecuador, Argentina and Bolivia.

Other countries are noticing the effects. Studies show snow and ice cover in the eastern Himalayas has shrunk by about 30% since the 1970s. Melting glaciers have created lakes in the mountains which could burst and cause widespread flooding. Of 150 glaciers that once stood in Glacier National Park in the northern US, only 27 remain. The US Environmental Protection Agency says the biggest are a third the size they were in 1850. Continued warming could melt them completely by 2030.

These ideas are still laboratory dreams. The common thread in these research projects and in product development at many other food companies is nanotechnology, the name for a growing number of techniques for manipulating matter in dimensions as small as single molecules.

Food companies remain wary of pushing the technology--which is named for the nanometer, or a billionth of a meter--too far and too fast for safety-conscious consumers. But they are tantalized by nanotechnology's capacity to create valuable and sometimes novel forms of everyday substances, like food ingredients and packaging materials, simply by reducing them to sizes that once seemed unimaginable.

Most of the hoopla and a lot of the promise for nanotechnology lies in other industries, including electronics, energy and medicine. But the first generation of nanotechnology-based food industry products, including synthetic food colorings, frying oil preservatives and packaging coated with antimicrobial agents, has quietly entered the market.

The commercial uses of the technology now add up to a $410 million sliver of the $3 trillion global food market, according to Cientifica, a British market research firm that specializes in nanotechnology coverage. Cientifica forecasts that nanotechnology's share will grow to $5.8 billion by 2012, as other uses for it are developed.

A challenge for regulators

Mindful of the adverse reaction from some consumers over the introduction of genetically engineered crops, the food industry hopes regulators will come up with supportive guidelines that will also allay consumers' fears. That has put a spotlight on the Food and Drug Administration's first public hearing Tuesday on how it should regulate nanotechnology, with a portion of the agenda specifically about food and food additives. No policy changes are expected this year.

"To their credit, the FDA is trying to get a handle on what's out there," said Michael K. Hansen, senior scientist at Consumers Union, one of 30 groups that have signed up to speak at the meeting.

But coping with nanotechnology will be a daunting challenge for the agency, according to a report last week by a former senior FDA official, whose analysis was sponsored by the Pew Charitable Trusts and the Woodrow Wilson International Center for Scholars, a Washington policy group. Michael R. Taylor, a former deputy commissioner for policy at the agency, said the FDA lacked the resources and, in the case of cosmetics, dietary supplements and food, the full legal authority needed to protect consumers and also foster innovation.

Industry representatives and analysts are worried that nanotechnology will suffer the same fate as genetic engineering, which was quickly embraced as a breakthrough for drug makers but has been fiercely opposed, especially in Europe, when used in crops, fish and livestock.

Many of the same groups fighting genetic engineering in agriculture have been arguing for regulators to clamp down on nanotechnology, in general, and its use in food and cosmetics, in particular, until more safety testing has been completed.

"I'm amazed at how far it's gone already," said Ronnie Cummins, director of the Organic Consumers Group, an advocate for organic products based in Finland, Minn. "Compared to nanotechnology, I think the threat of genetic engineering is tame."

So far, there have been no confirmed reports of public health or environmental problems related to nanotechnology. But troubling laboratory tests suggest some nanoscale particles may pose novel health risks by, for instance, slipping easily past barriers to the brain that keep larger particles out. Thus, the same attributes that could make the technology valuable for delivering drugs could also make it hazardous.

More important, everyone agrees that there have been few rigorous studies of the actual behavior of the newly engineered nanoscale materials in humans and the environment. Those that have been completed fall far short of duplicating the range of conditions the nanoparticles would encounter in general commerce. And few laboratory studies have focused on the fate of particles that are eaten rather than inhaled or injected.

"Lack of evidence of harm should not be a proxy for reasonable certainty of safety," the Consumers Union said in testimony submitted to the FDA for today's meeting. The language was carefully chosen. "Reasonable certainty of safety" is what food companies must demonstrate to the FDA before they can introduce a new food additive.

The Consumers Union and some other groups are suggesting that the agency automatically classify all new nanoscale food ingredients, including those now classified as safe in larger sizes, as new additives. And they want the same standards extended to cover food supplement companies, some of which have been marketing traditional herbal and mineral therapies in what they say are new nanoscale forms that increase their effectiveness. Some are also calling for mandatory labeling of products with synthetic nanoscale ingredients, no matter how small the quantity.

FDA officials said last week that treating every new nanotechnology product that consumers swallow as a food additive might compromise the agency's mandate to foster innovation and might not be within its authority. Such a move would also be hobbled by the lack of agreement on safety testing standards for the wide range of nanoscale innovations in the pipeline. In addition, the agency lacks the staff to handle that scale of oversight.

"That would be a sea change for us," said Laura Tarantino, director of the FDA's Office of Food Additive Safety.

Simply defining nanotechnology may also be a hurdle. BASF has been widely considered a pioneer for products like its synthetic lycopene, an additive that substitutes for the natural lycopene extracted from tomatoes and other fruits. Lycopene, widely used as a food coloring, is increasingly valued for its reported heart and anticancer benefits. But BASF's particles average 200 to 400 nanometers in diameter, about the same as the natural pigment, and well above the 100-nanometer threshold that many experts consider true nanotechnology.

Unilever has never disclosed the dimensions of its shrunken fat particles. Trevor Gorin, a Unilever spokesman in Britain, said in an e-mail message that reports about the project have been misleading.

Given the uncertainty about the risks of consuming new nano products, many analysts expect near-term investment to focus on novel food processing and packaging technology. That is the niche targeted by Sunny Oh, whose start-up company, OilFresh, based in Sunnyvale, Calif., is marketing a novel device to keep frying oil fresh. OilFresh grinds zeolite, a mineral, into tiny beads averaging 20 nanometers across and coats them with an undisclosed material. Packed into a shelf inside the fryer, the beads interfere with chemical processes that break down the oil or form hydrocarbon clusters, Oh says. As a result, restaurants can use oil longer and transfer heat to food at lower temperatures, although they still need traditional filters to remove food waste from the oil.

An aversion to controversey

Oh said OilFresh will move beyond restaurants into food processing by the end of the month, when it delivers a 1,000-ton version of the device to a "midsized potato chip company" that he said did not want to be identified.

The desire to avoid controversy has made even the largest food companies, like Kraft Foods, leery about discussing their interest in nanotechnology. Kraft, the second-largest food processor after Nestle, was considered the industry's nanotechnology pacesetter in 2000. That is when it announced the founding of an international alliance of academic researchers and experts at government labs to pursue basic research in nanotechnology sponsored by Kraft.

The Nanotek Consortium, as Kraft called the group, produced a number of patents for the company, but Kraft pulled back from its high-profile connection with nanotechnology two years ago. Manuel Marquez, the research chemist Kraft appointed to organize the consortium, moved to Philip Morris USA, a sister subsidiary of Altria that now sponsors the consortium under a new name--the Interdisciplinary Network of Emerging Science and Technologies.

Kraft still sends researchers to industry conferences to make what it calls "generic" presentations about the potential uses of nanotechnology in the food industry. But the company declines to specify its use of or plans for the technology.

FDA officials say companies like Kraft are voluntarily but privately providing them with information about their activities. But many independent analysts say the level of disclosure to date falls far short of what will be needed to create public confidence.

"Most of the information is in companies and very little is published," said Jennifer Kuzma, an associate director of the Center for Science, Technology, and Public Policy at the University of Minnesota, who has been tracking reports of nanotechnology use in food and agriculture.

"Because BMD is strongly linked with fracture risk, and because cola is a popular beverage, this is of considerable public health importance," the authors write in the American Journal of Clinical Nutrition.

Studies in teen girls have tied heavy soft drink consumption to fractures and lower BMD, the researchers note, but it is not clear if this is because they're drinking less milk, or if it is due to any harmful effects of soda itself.

To investigate this question in adults, the researchers measured BMD in the spine and at three points on the hips in 1,413 women and 1,125 men participating in a study of the bone-thinning disease osteoporosis.

While there was no association between soft drinks in general and BMD, the researchers found that women who drank the most cola had significantly less dense bones in their hips. The greater their intake, the thinner the bones, and the relationship was seen for diet, regular, and non-caffeinated colas.

Cola consumption had no effect on BMD in men.

Women who drank more cola did not drink less milk, but they did consume less calcium and had lower intakes of phosphorus in relation to calcium. Cola contains phosphoric acid, the researchers note, which impairs calcium absorption and increases excretion of the mineral. Caffeine has also been linked to osteoporosis, they add.

"No evidence exists that occasional use of carbonated beverages, including cola, is detrimental to bone," they note. "However, unless additional evidence rules out an effect, women who are concerned about osteoporosis may want to avoid the regular use of cola beverages."

"If you can take the active components out, the approach would be much more versatile," say Stephen Britland, who is developing the dressing at the University of Bradford in the UK.

Repair cells

Britland and colleagues established the wound-healing capacity of "maggot juice" by applying extracts of the secretion to layers of cells that mimic skin. When they created artificial, circular "wounds" in the layers, the wounds healed fastest when exposed to the extracts.

They suggest that protease enzymes in the juice enable repair cells to move more swiftly and freely within the wound site. "They all march in unison and fill the hole significantly quicker," says co-team leader, David Pritchard at the University of Nottingham in the UK.

The researchers showed that the holes healed just as quickly whether the juice was applied directly or in a prototype gel which could be developed into a wound dressing.

Britland says delivering precisely the right dose of maggot enzymes is crucial. "Too little and the clinical objectives will not be met, too much could disrupt tissue regeneration," he says. But he adds that suspending the enzymes in the gel allows quantities to be carefully controlled.

A tissue-regenerating dressing incorporating the enzymes is being developed commercially by AGT Sciences in Bradford, UK, a company spun out from the university, but Britland says it will be at least another three years before this is ready to market. The researcher's next step, beginning in November 2006, is to scrutinise in unprecedented detail how maggots heal wounds in real patients.

Journal reference: Biotechnology Progress (DOI: 10.1021/bp0601600)

Renato Solidum, director of the Philippine Institute of Volcanology and Seismology (PHIVOLCS), said several villages in the nearby towns of Irosin and Bulusan were covered by the ash fall.

He said volcanologists were studying whether the volcano was nearing a violent eruption. He added that PHIVOLCS has not yet raised the current alert level, which was at one out of five.

Bulusan volcano has been spewing columns of ash and showing other signs of unrest since March.

The 1,565-metre Bulusan is one of the country's most active volcanoes. It has erupted 15 times, with the most recent recorded in 1994 and 1995.

Jeff and Pam Holmberg are two of those people.

The husband and wife were watching television in their house north of Westcliffe when Jeff looked out the window and saw the fireball soar over the Sangre de Cristo mountain range.

Pam was dozing off after a full day of football watching.

"I started hootin' and hollerin' and she came out of the chair like a shot," Jeff Holmberg said.

He and his wife ran outside in time to see the main fireball break into three or four pieces. Jeff Holmberg scrambled up a ladder to the roof and watched the meteor pieces disappear into the northeast horizon toward Colorado Springs.

"It was a big, bright light with a smoke trail behind it," he said. "It looked like the landing light on a big jet."

The Holmbergs estimated the fireball took 20 seconds to pass from horizon to horizon.

"I was just incredible how close it seemed," Pam Holmberg said. "It was floating across, so bright, it seemed like you could just reach out and touch it."

Eyewitnesses and cameras that capture the whole sky in Colorado, New Mexico and Arizona caught the fireball at 11:16 p.m on Oct. 1, said Chris Peterson, an astronomer and a researcher at the Denver Museum of Nature and Science.

Witnesses also reported hearing the sonic boom, a sound similar to thunder. The sonic boom is heard several minutes after the fireball is seen because it takes the sound that long to travel to earth from more than 20 miles in the air, Peterson said.

The fireball traveled generally southwest to northeast, beginning northeast of Phoenix, cutting across northwest New Mexico and ending east of Colorado Springs.

It was captured by sky cameras at the Guffey School and at Cloudbait Observatory north of Guffey, which Peterson runs, as well as by sky cameras in New Mexico.

Camera data suggests the full flight lasted at least 45 seconds - an eternity for a meteor, Peterson said.

"It was very, very long," he said. "It was going about as slow as a meteor gets. To see a meteor that goes on for more than half a minute is remarkable."

Witnesses and cameras show the meteor breaking into multiple pieces in a long train extending at least 70 miles from southern Colorado to Colorado Springs, Peterson said. He described the breakup pattern as "extremely unusual." Usually meteors fade out, but videos show this one split into a long string of individual fireballs, Peterson said.

Meteorites may have dropped over the central San Luis Valley, in the Sangre de Cristo mountains, across the Wet Mountain Valley and continuing to Ellicott, 20 miles east of Colorado Springs.

Ward, who is from Arizona, is focusing his hunt for space rocks between between Penrose and Ellicott.

He started by talking to people at fire stations, gas stations and convenience stores and asking if anyone had seen or heard anything unusual.

Ward found Jeff Holmberg at the Wet Mountain Fire Protection District, where Homberg volunteers. Holmberg had told his skeptical fellow firefighters about what he'd seen.

"The boys at the fire station just kind of grinned and shook their heads and asked me about aliens and stuff," he said.

A couple of days later, Ward walked in and asked if anyone had seen a possible meteor. Holmberg invited Ward to his house for breakfast and told him his story over biscuits and gravy.

The men climbed on Holmberg's roof. Ward took compass readings and gathered other information he'll use to estimate the fireball's flight path.

Meteorites are typically black, unusual-looking rocks with rounded surfaces, Ward said. They're usually heavier than other rocks the same size and 90 percent are magnetic.

He finds about 80 meteorites a year, some of them hundreds of years old. It's rare and more scientifically significant to find meteorites that have just fallen.

"This was in space a week ago," Ward said. "It's extremely fresh. It's important to get it into a lab as soon as possible so it can be analyzed."

While Ward concentrates on where meteorites might have ended up, Peterson is more interested in where the space rocks came from.

With good reports from several locations, scientists can estimate the orbit of the meteor before it entered Earth's atmosphere. Then, if meteorites are found, they can be tested to provide scientifically valuable information about the parent body, Peterson said.

They can also be valuable to dealers and collectors, who base their worth on factors such as where the meteorite is from and whether there were witnesses to the meteor fall.

A witnessed, fresh fall that turns out to be from the moon or Mars might be worth more than $1 million. Other meteorites have little monetary value.

Rare event

A transit is a relatively rare occurrence. As seen from Earth, only transits of Mercury and Venus are possible. This is the second of 14 transits of Mercury that will occur during the 21st century.

The entire transit from start to finish will be visible in its entirety only from the west coast of North America, (including central and southern Alaska), Hawaii, New Zealand and the east coast of Australia. From Australia and New Zealand the transit will occur on the morning of Nov. 9.

From the United States, those situated to the east of a line running from roughly northern Idaho to westernmost Texas will be able to see the beginning stages of the transit, but sunset will intervene before Mercury can move off the Sun's disk.

What to expect

The tiny disk of Mercury will begin moving on to the Sun at 2:12 p.m. EST (11:12 a.m. PST) and will take about 2 minutes to move completely onto the Sun's disk. The planet will be recognizable along the lower left edge of the Sun as a tiny, black, sharp-edged dot, but having only 1/194 the Sun's diameter.

Just under five hours later, Mercury will reach the Sun's right (west) edge. Mercury will take about 2 minutes to move completely off the disk of the Sun, beginning at 4:08 p.m. PST.

In those eastern regions where the Sun will set before the transit ends, a good observing site should have a low horizon to the south of due west. It is a good precaution to check the Sun's setting point a day or two beforehand, to verify that trees or buildings do not block the view.

Safe equipment needed

Unlike a transit of Venus, a transit of Mercury is not visible with the unaided eye. A telescope must be used, magnifying at least 30-power to bring out the "dark dot" of Mercury in silhouette against the Sun's disk.

Eye safety is always a prime concern when dealing with the Sun. Never look directly at the Sun through a telescope! Rather, you should project the enlarged solar image onto a white card or screen or use proper, approved solar filters.

SPACE.com will provide more observing details and information about the transit on Nov. 3.