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2-Year Study of Polar Changes Set to Begin
By ANDREW C. REVKIN, The New York Times, February 26, 2007
Scientists from more than 60 countries are preparing to fan out around the North and South Poles in an ambitious two-year effort to understand the vital, shifting dynamics of ice, oceans and life at the ends of the earth.
With a budget of about $350 million spread over more than 120 projects, researchers will camp on drifting Arctic Ocean sea ice and trek to largely uncharted Antarctic mountains.
They will use gliding underwater robots, giant icebreaking ships, satellites and other technologies to explore polar climate, biology, geology and ocean chemistry, and they will undertake physics and astronomy studies that can be done only at the poles.
A central goal of the effort — called the International Polar Year despite its two-year timetable — is to clarify the role of greenhouse gases and global warming in the rapid changes that are already occurring at both poles.
In the Arctic, sea ice in summer has been in an accelerating retreat. In parts of Antarctica that are warming, coastal ice shelves and inland ice sheets have been disintegrating and surging seaward in ways that could hint at a faster rise in global sea levels in coming decades.
But at both poles, scientists say, questions still outnumber answers.
The project will formally begin Thursday. Opening ceremonies will be held today in Washington, London and Strasbourg, France.
This is just the fourth such integrated Arctic and Antarctic science effort since 1881. The last such project, which included broader studies of the oceans and earth, ended in 1958.
John H. Marburger III, the science adviser to President Bush, said the United States had a vital interest in studies at both poles.
“The North Pole is in our backyard,” he said in an e-mail message. “The U.S. has huge geopolitical interests in the Arctic region, and we need to understand the changes that are taking place there. Many other countries have direct economic interests in the Arctic, and all are served by joining forces in I.P.Y. research. Additionally the rapidly diminishing ice in the Arctic is creating new opportunities for transport and marine resource development.
“The South Pole is on a major continent, still poorly understood,” Dr. Marburger added. “With the exception of the Arctic Ocean, all the oceans of the Earth communicate in the Antarctic region, which makes it a significant factor in processes of global change, particularly as influenced by ocean currents. It offers remarkable opportunities for astronomy, and is already the site of a sophisticated neutrino detector utilizing the deep and stable ice deposits near the pole.
“Antarctic marine organisms are an integral part of the increasingly vulnerable marine wildlife environment, and play a significant role in the world food chain.”
Other studies will examine the impact of pollution, retreating sea ice, thawing tundra and other fast-changing conditions on native communities ringing the Arctic Ocean.
Some projects are utilitarian, like fresh surveys of ocean-bottom terrain and studies sifting for hints of oil and gas or other natural resources.
But the most pressing questions being pursued relate to warming caused by the atmospheric buildup of heat-trapping gases like carbon dioxide. Experts involved with the polar year say the earth’s coldest places are likely to be especially affected.
“The poles are going to lead the way in climate change,” said Ted Scambos, a researcher at the National Snow and Ice Data Center in Boulder, Colo. “To know what we’re in for in the next 10 years, in sea level or in climate, we need to look at the poles now. They are the amplifiers of the small warming that greenhouse gases cause.”
Particularly urgent, many experts said, is the need to improve understanding of the complicated forces that might cause warming ice sheets in Greenland and parts of Antarctica to flow more quickly into the sea.
Greenland’s vast ice cap is twice the size of California, and it holds as much water as the Gulf of Mexico. If it all melted, sea levels from Boston to Bangladesh would rise more than 20 feet, experts say.
The latest report on sea level trends by the United Nations Intergovernmental Panel on Climate Change said such melting could take a millennium or more. But because of a lack of long-term measurements and poor understanding of the physics of ice, that analysis largely excluded hints of an accelerating flow of ice and meltwater from Greenland into the seas.
“The change of phase from snow and ice to water is the biggest tipping point in the earth’s system, and so although the International Polar Year covers a huge range of science, for me the big issue is climate change and the impact that it’s having here,” said Chris Rapley, the director of the British Antarctic Survey, in a message from Antarctica.
“Over the next two years, I’m looking forward to major progress on key issues,” he said. “The trillion-dollar question from the point of view of sea-level rise: how much, how quickly?”
The climatic equations are complicated. Over the two years — researchers want to study both regions through complete summer and winter cycles — teams will examine the effects of shifting solar activity, greenhouse gases and the synthetic chemicals that harm the ozone layer, which have an outsize impact at the poles.
Other scientists will intensively study the warming of the permafrost and tundra across vast stretches of northern continents for signs that thawing ground, bogs and lakes are giving up emissions of methane and carbon dioxide.
Marine scientists will plumb the Arctic Ocean and productive waters around Antarctica to see how shifts in sea ice and ocean currents affect species from clouds of shrimplike krill to whales, penguins and polar bears.
Most of these subjects have already been a focus of research. But several veteran earth and polar scientists said periodic intensive efforts like the polar years helped them to generate fresh ideas, collect data that individual countries lack the resources to pursue, and refresh the public’s appreciation for the splendor of the world’s least-habitable places.
Walter Munk, 89, an emeritus professor of geophysics at the University of California, San Diego, who helped run the 1957-58 effort (called the International Geophysical Year), said that what was needed most was long-term studies of earth’s poles and oceans.
But he added that the polar year would provide a necessary short-term focus. “Our society is poorly conditioned for sustained efforts,” he said in an e-mail message. “I rather think that without the occasional burst there would have been even less of a sustained effort.”
A quasi-crystalline Penrose pattern at the Darb-i Imam shrine in Isfahan, Iran.
In Medieval Architecture, Signs of Advanced Math
By JOHN NOBLE WILFORD, The New York Times, February 27, 2007
In the beauty and geometric complexity of tile mosaics on walls of medieval Islamic buildings, scientists have recognized patterns suggesting that the designers had made a conceptual breakthrough in mathematics beginning as early as the 13th century.
A new study shows that the Islamic pattern-making process, far more intricate than the laying of one’s bathroom floor, appears to have involved an advanced math of quasi crystals, which was not understood by modern scientists until three decades ago.
The findings, reported in the current issue of the journal Science, are a reminder of the sophistication of art, architecture and science long ago in the Islamic culture. They also challenge the assumption that the designers somehow created these elaborate patterns with only a ruler and a compass. Instead, experts say, they may have had other tools and concepts.
Two years ago, Peter J. Lu, a doctoral student in physics at Harvard University, was transfixed by the geometric pattern on a wall in Uzbekistan. It reminded him of what mathematicians call quasi-crystalline designs. These were demonstrated in the early 1970s by Roger Penrose, a mathematician and cosmologist at the University of Oxford.
Mr. Lu set about examining pictures of other tile mosaics from Afghanistan, Iran, Iraq and Turkey, working with Paul J. Steinhardt, a Princeton cosmologist who is an authority on quasi crystals and had been Mr. Lu’s undergraduate adviser. The research was a bit like trying to figure out the design principle of a jigsaw puzzle, Mr. Lu said in an interview.
In their journal report, Mr. Lu and Dr. Steinhardt concluded that by the 15th century, Islamic designers and artisans had developed techniques “to construct nearly perfect quasi-crystalline Penrose patterns, five centuries before discovery in the West.”
Some of the most complex patterns, called “girih” in Persian, consist of sets of contiguous polygons fitted together with little distortion and no gaps. Running through each polygon (a decagon, pentagon, diamond, bowtie or hexagon) is a decorative line. Mr. Lu found that the interlocking tiles were arranged in predictable ways to create a pattern that never repeats — that is, quasi crystals.
“Again and again, girih tiles provide logical explanations for complicated designs,” Mr. Lu said in a news release from Harvard.
He and Dr. Steinhardt recognized that the artisans in the 13th century had begun creating mosaic patterns in this way. The geometric star-and-polygon girihs, as quasi crystals, can be rotated a certain number of degrees, say one-fifth of a circle, to positions from which other tiles are fitted. As such, this makes possible a pattern that is infinitely big and yet the pattern never repeats itself, unlike the tiles on the typical floor.
This was, the scientists wrote, “an important breakthrough in Islamic mathematics and design.”
Dr. Steinhardt said in an interview that it was not clear how well the Islamic designers understood all the elements they were applying to the construction of these patterns. “I can just say what’s on the walls,” he said.
Mr. Lu said that it would be “incredible if it were all coincidence.”
“At the very least,” he said, “it shows us a culture that we often don’t credit enough was far more advanced than we ever thought before.”
From a study of a few hundred examples, Mr. Lu and Dr. Steinhardt determined that the technique was fully developed two centuries later in mosques, palaces, shrines and other buildings. They noted that “a nearly perfect quasi-crystalline Penrose pattern” is found on the Darb-i Imam shrine in Isfahan, Iran, which was built in 1453. The researchers described how the architects there had created overlapping patterns with girih tiles at two sizes to produce nearly perfect quasi-crystalline patterns.
In the report, Mr. Lu and Dr. Steinhardt said the examples they had studied so far “fall just short of being perfect quasi crystals; there may be more interesting examples yet to be discovered.”
In a separate article in Science, some experts in the math of crystals questioned if the findings were an entirely new insight. In particular, Emil Makovicky of the University of Copenhagen in Denmark said the new report failed to give sufficient credit to an analysis he published in 1992 of mosaic patterns on a tomb in Iran.
Mr. Lu and Dr. Steinhardt said they regretted what they called a misunderstanding. They pointed out that the length of their report was strictly enforced by journal editors, but it did include two footnotes to Dr. Makovicky’s research. None of the referees or editors who reviewed the paper, Dr. Steinhardt said, asked for more attention to the previous research.
Although their work had some elements in common with Dr. Makovicky’s, Dr. Steinhardt said in an interview that their research dealt with not one but a “whole sweep of tilings” interpreted through a few hundred examples.
The article quoted two other experts, Dov Levine and Joshua Socolar, physicists at the Israel Institute of Technology in Haifa and Duke University, respectively, as agreeing that Dr. Makovicky deserved more credit. But, the article noted, they said the Lu-Steinhardt research had “generated interesting and testable hypotheses.”
Spacecraft Closes In for a Look at Jupiter, With Pluto Next on the List
By WARREN E. LEARY, The New York Times, February 27, 2007
WASHINGTON, Feb. 26 — The New Horizons spacecraft, launched from Earth by NASA some 13 months ago, is moving in for a close encounter with Jupiter on Wednesday that should let it test its suite of instruments before being flung off toward the distant target of Pluto and its trio of moons.
The half-ton, atomic-powered robot craft is to make more than 700 observations of Jupiter and its four largest moons by June. A period of high-intensity observations began last Saturday and will peak after the craft makes its closest approach to Jupiter on Wednesday, passing 1.4 million miles from the center of the giant planet.
Jupiter’s gravity will accelerate the spacecraft by 9,000 miles per hour, flinging it toward Pluto at 52,000 miles per hour. Even with the speed boost, which knocks off three years of travel time, New Horizons will take eight more years to reach the Pluto system for a close-up look in July 2015, when Pluto will be 3 billion miles from Earth, a distance requiring almost four and a half hours for a radio signal to pass between them.
“Our highest priority is to get the spacecraft safely through the gravity assist and on its way to Pluto,” said Alan Stern of the Southwest Research Institute in Boulder, Colo., the mission’s principal scientist and team leader. “But this is also a big stress test for our primary mission to Pluto. We want to exercise our spacecraft hard enough to turn up any problems and to fully test our procedures.”
New Horizons is powered by a small plutonium-fueled electric generator, and its instruments include three cameras, for visible-light, infrared and ultraviolet images, a space-dust collector and three spectrometers to study the chemical composition and temperatures of the worlds it investigates.
John Spencer, a mission scientist who is also from the Southwest Research Institute, said New Horizons carried more advanced instruments than any of the seven spacecraft that previously visited Jupiter and would be making unique observations. “We will not be repeating what has already been done,” he said.
Scientists plan for the spacecraft to make three-dimensional movies of the turbulent area near Jupiter’s famous Great Red Spot, a centuries-old giant hurricane; examine auroras above the atmosphere in different wavelengths of light; and make the first edge-on observations of the planet’s tenuous ring system in hopes of finding some tiny satellites there, Dr. Spencer said.
The spacecraft will also make a major study of Jupiter’s enormous magnetosphere, a cocoon of charged particles from the Sun that are trapped and channeled around the planet by its magnetic field. In the months after the Jupiter fly-by, plans call for New Horizons to make the first trip down the magnetosphere’s long tail of high-energy particles that extend tens of millions of miles beyond the planet.
Much of the data collected during the Jupiter encounter will be recorded aboard the spacecraft and sent back to Earth days or weeks later, just as New Horizons is scheduled to do when it makes its closest pass by Pluto, its large moon Charon and the smaller satellites Nix and Hydra on July 14, 2015.
Months after the Jupiter encounter, the $700 million project will go to sleep for much of the cruise period to Pluto. New Horizons will be put into a “hibernation mode” with most of its systems and instruments turned off to reduce wear and tear and to save power. Operators are to wake the spacecraft once a year during the long journey to check its status and correct its flight path.
Christopher Peterson of the Glen Canyon Institute in the Escalante River in Utah. A high-water mark remains, halfway up the rock wall.
That ‘Drought’ in Southwest May Be Normal, Report Says
By CORNELIA DEAN, The New York Times, February 22, 2007
The Colorado River Basin is more prone to drought than had been thought, a panel of experts reported yesterday, and as the climate warms and the population in the region grows, pressure on water supplies will become greater.
The severe droughts the region suffered in the 1990s and early 2000s would not stand out in the record of the last few centuries, the panel said, and the future presents “a sobering prospect for elected officials and water managers.” The panel said residents of the region should prepare for more frequent and more severe dry spells, and “costly, controversial and unavoidable trade-offs” in water use.
The data discussed in the report have been published before in scholarly journals and elsewhere. But Ernest T. Smerdon, a former dean of the College of Engineering and Mines at the University of Arizona, who led the panel, said its members hoped with this publication to pull the findings into a single document that ordinary people could understand.
Severe droughts will recur, Dr. Smerdon said, “and we better be prepared. That is the message.” He spoke at a news conference yesterday in Las Vegas, where the report was made public.
The panel recommended an “action-oriented” study of water use patterns and demands, including drought planning, population projections and possible effects of transferring water to urban areas from agriculture, still the dominant consumer. Dialogue between policy makers and scientists who study water issues should be “a permanent fixture within the basin,” it said.
The panel, organized by the National Research Council, the research arm of the National Academy of Science, noted that the water allocation agreement for the basin, the Colorado River Compact, was negotiated in 1922 based on river flow records dating to the 1890s, when gauging stations were established. The agreement assumed that the annual river flow was 16.4 million acre feet — enough to cover 16.4 million acres to a depth of one foot.
But for some time, the panel said, researchers have known that the early 20th century was unusually wet and that 15 million acre feet was a more accurate estimate of the flow. Recent studies based on tree rings put the figure lower still — as low as 13 million acre feet — and suggest that “drought episodes are a recurrent and integral feature of the region’s climate.”
Because trees grow more when it is wet, scientists use tree ring size as an indicator of water abundance. The report says the federal Bureau of Reclamation and other agencies requested the panel’s review in the wake of the new findings.
Global warming is already making things worse, the experts said. For one thing, warmer weather means less precipitation in the form of snow, which is stored in the region’s mountain snowpack. And the snowpack itself forms later and melts sooner each winter. As a result, the steady reliability of snowpack water storage is compromised. Also, warmer weather itself increases consumer, environmental and agricultural demands for water.
Rainfall patterns are difficult to predict, another panel member, Connie A. Woodhouse, a geographer at the University of Arizona, said at the news conference. But the report said it was probable that the region would experience less precipitation over all in a warmer world.
Cloud-seeding, water desalinization and improved underground water storage have yet to emerge as solutions, the report said, and even conservation, while helpful, “is no panacea,” Dr. Smerdon said.
The report, which is available at www.nationalacademies.org, notes that the basin, 240,000 square miles in Wyoming, Utah, Colorado, New Mexico, Arizona, Nevada, California and Mexico, has seen rapid population growth in recent decades. Until about 30 years ago, the panel wrote, growing demands for water were met through building dams and reservoirs. But today, the report says, “prospects for constructing additional large dams in the Colorado River basin have diminished.”
Instead, “there is going to have to be some kind of reallocation of who gets the water,” said Richard Seager, a climate expert at the Lamont Doherty Earth Observatory, who was not involved in the panel’s report.
Dr. Seager, who studies the drought history of North America, said that it was “silly” to put golf courses in the region’s desert areas and that hotels and other businesses were already installing water-conserving toilets and other fixtures.
But he added, referring to cattle and cotton raising, “Let’s think whether it makes sense to have all this subsidized agriculture in the region, people who aren’t even paying the full cost of the water they do use.”
By ANDREW C. REVKIN, The New York Times, February 26, 2007
Scientists from more than 60 countries are preparing to fan out around the North and South Poles in an ambitious two-year effort to understand the vital, shifting dynamics of ice, oceans and life at the ends of the earth.
With a budget of about $350 million spread over more than 120 projects, researchers will camp on drifting Arctic Ocean sea ice and trek to largely uncharted Antarctic mountains.
They will use gliding underwater robots, giant icebreaking ships, satellites and other technologies to explore polar climate, biology, geology and ocean chemistry, and they will undertake physics and astronomy studies that can be done only at the poles.
A central goal of the effort — called the International Polar Year despite its two-year timetable — is to clarify the role of greenhouse gases and global warming in the rapid changes that are already occurring at both poles.
In the Arctic, sea ice in summer has been in an accelerating retreat. In parts of Antarctica that are warming, coastal ice shelves and inland ice sheets have been disintegrating and surging seaward in ways that could hint at a faster rise in global sea levels in coming decades.
But at both poles, scientists say, questions still outnumber answers.
The project will formally begin Thursday. Opening ceremonies will be held today in Washington, London and Strasbourg, France.
This is just the fourth such integrated Arctic and Antarctic science effort since 1881. The last such project, which included broader studies of the oceans and earth, ended in 1958.
John H. Marburger III, the science adviser to President Bush, said the United States had a vital interest in studies at both poles.
“The North Pole is in our backyard,” he said in an e-mail message. “The U.S. has huge geopolitical interests in the Arctic region, and we need to understand the changes that are taking place there. Many other countries have direct economic interests in the Arctic, and all are served by joining forces in I.P.Y. research. Additionally the rapidly diminishing ice in the Arctic is creating new opportunities for transport and marine resource development.
“The South Pole is on a major continent, still poorly understood,” Dr. Marburger added. “With the exception of the Arctic Ocean, all the oceans of the Earth communicate in the Antarctic region, which makes it a significant factor in processes of global change, particularly as influenced by ocean currents. It offers remarkable opportunities for astronomy, and is already the site of a sophisticated neutrino detector utilizing the deep and stable ice deposits near the pole.
“Antarctic marine organisms are an integral part of the increasingly vulnerable marine wildlife environment, and play a significant role in the world food chain.”
Other studies will examine the impact of pollution, retreating sea ice, thawing tundra and other fast-changing conditions on native communities ringing the Arctic Ocean.
Some projects are utilitarian, like fresh surveys of ocean-bottom terrain and studies sifting for hints of oil and gas or other natural resources.
But the most pressing questions being pursued relate to warming caused by the atmospheric buildup of heat-trapping gases like carbon dioxide. Experts involved with the polar year say the earth’s coldest places are likely to be especially affected.
“The poles are going to lead the way in climate change,” said Ted Scambos, a researcher at the National Snow and Ice Data Center in Boulder, Colo. “To know what we’re in for in the next 10 years, in sea level or in climate, we need to look at the poles now. They are the amplifiers of the small warming that greenhouse gases cause.”
Particularly urgent, many experts said, is the need to improve understanding of the complicated forces that might cause warming ice sheets in Greenland and parts of Antarctica to flow more quickly into the sea.
Greenland’s vast ice cap is twice the size of California, and it holds as much water as the Gulf of Mexico. If it all melted, sea levels from Boston to Bangladesh would rise more than 20 feet, experts say.
The latest report on sea level trends by the United Nations Intergovernmental Panel on Climate Change said such melting could take a millennium or more. But because of a lack of long-term measurements and poor understanding of the physics of ice, that analysis largely excluded hints of an accelerating flow of ice and meltwater from Greenland into the seas.
“The change of phase from snow and ice to water is the biggest tipping point in the earth’s system, and so although the International Polar Year covers a huge range of science, for me the big issue is climate change and the impact that it’s having here,” said Chris Rapley, the director of the British Antarctic Survey, in a message from Antarctica.
“Over the next two years, I’m looking forward to major progress on key issues,” he said. “The trillion-dollar question from the point of view of sea-level rise: how much, how quickly?”
The climatic equations are complicated. Over the two years — researchers want to study both regions through complete summer and winter cycles — teams will examine the effects of shifting solar activity, greenhouse gases and the synthetic chemicals that harm the ozone layer, which have an outsize impact at the poles.
Other scientists will intensively study the warming of the permafrost and tundra across vast stretches of northern continents for signs that thawing ground, bogs and lakes are giving up emissions of methane and carbon dioxide.
Marine scientists will plumb the Arctic Ocean and productive waters around Antarctica to see how shifts in sea ice and ocean currents affect species from clouds of shrimplike krill to whales, penguins and polar bears.
Most of these subjects have already been a focus of research. But several veteran earth and polar scientists said periodic intensive efforts like the polar years helped them to generate fresh ideas, collect data that individual countries lack the resources to pursue, and refresh the public’s appreciation for the splendor of the world’s least-habitable places.
Walter Munk, 89, an emeritus professor of geophysics at the University of California, San Diego, who helped run the 1957-58 effort (called the International Geophysical Year), said that what was needed most was long-term studies of earth’s poles and oceans.
But he added that the polar year would provide a necessary short-term focus. “Our society is poorly conditioned for sustained efforts,” he said in an e-mail message. “I rather think that without the occasional burst there would have been even less of a sustained effort.”
A quasi-crystalline Penrose pattern at the Darb-i Imam shrine in Isfahan, Iran.
In Medieval Architecture, Signs of Advanced Math
By JOHN NOBLE WILFORD, The New York Times, February 27, 2007
In the beauty and geometric complexity of tile mosaics on walls of medieval Islamic buildings, scientists have recognized patterns suggesting that the designers had made a conceptual breakthrough in mathematics beginning as early as the 13th century.
A new study shows that the Islamic pattern-making process, far more intricate than the laying of one’s bathroom floor, appears to have involved an advanced math of quasi crystals, which was not understood by modern scientists until three decades ago.
The findings, reported in the current issue of the journal Science, are a reminder of the sophistication of art, architecture and science long ago in the Islamic culture. They also challenge the assumption that the designers somehow created these elaborate patterns with only a ruler and a compass. Instead, experts say, they may have had other tools and concepts.
Two years ago, Peter J. Lu, a doctoral student in physics at Harvard University, was transfixed by the geometric pattern on a wall in Uzbekistan. It reminded him of what mathematicians call quasi-crystalline designs. These were demonstrated in the early 1970s by Roger Penrose, a mathematician and cosmologist at the University of Oxford.
Mr. Lu set about examining pictures of other tile mosaics from Afghanistan, Iran, Iraq and Turkey, working with Paul J. Steinhardt, a Princeton cosmologist who is an authority on quasi crystals and had been Mr. Lu’s undergraduate adviser. The research was a bit like trying to figure out the design principle of a jigsaw puzzle, Mr. Lu said in an interview.
In their journal report, Mr. Lu and Dr. Steinhardt concluded that by the 15th century, Islamic designers and artisans had developed techniques “to construct nearly perfect quasi-crystalline Penrose patterns, five centuries before discovery in the West.”
Some of the most complex patterns, called “girih” in Persian, consist of sets of contiguous polygons fitted together with little distortion and no gaps. Running through each polygon (a decagon, pentagon, diamond, bowtie or hexagon) is a decorative line. Mr. Lu found that the interlocking tiles were arranged in predictable ways to create a pattern that never repeats — that is, quasi crystals.
“Again and again, girih tiles provide logical explanations for complicated designs,” Mr. Lu said in a news release from Harvard.
He and Dr. Steinhardt recognized that the artisans in the 13th century had begun creating mosaic patterns in this way. The geometric star-and-polygon girihs, as quasi crystals, can be rotated a certain number of degrees, say one-fifth of a circle, to positions from which other tiles are fitted. As such, this makes possible a pattern that is infinitely big and yet the pattern never repeats itself, unlike the tiles on the typical floor.
This was, the scientists wrote, “an important breakthrough in Islamic mathematics and design.”
Dr. Steinhardt said in an interview that it was not clear how well the Islamic designers understood all the elements they were applying to the construction of these patterns. “I can just say what’s on the walls,” he said.
Mr. Lu said that it would be “incredible if it were all coincidence.”
“At the very least,” he said, “it shows us a culture that we often don’t credit enough was far more advanced than we ever thought before.”
From a study of a few hundred examples, Mr. Lu and Dr. Steinhardt determined that the technique was fully developed two centuries later in mosques, palaces, shrines and other buildings. They noted that “a nearly perfect quasi-crystalline Penrose pattern” is found on the Darb-i Imam shrine in Isfahan, Iran, which was built in 1453. The researchers described how the architects there had created overlapping patterns with girih tiles at two sizes to produce nearly perfect quasi-crystalline patterns.
In the report, Mr. Lu and Dr. Steinhardt said the examples they had studied so far “fall just short of being perfect quasi crystals; there may be more interesting examples yet to be discovered.”
In a separate article in Science, some experts in the math of crystals questioned if the findings were an entirely new insight. In particular, Emil Makovicky of the University of Copenhagen in Denmark said the new report failed to give sufficient credit to an analysis he published in 1992 of mosaic patterns on a tomb in Iran.
Mr. Lu and Dr. Steinhardt said they regretted what they called a misunderstanding. They pointed out that the length of their report was strictly enforced by journal editors, but it did include two footnotes to Dr. Makovicky’s research. None of the referees or editors who reviewed the paper, Dr. Steinhardt said, asked for more attention to the previous research.
Although their work had some elements in common with Dr. Makovicky’s, Dr. Steinhardt said in an interview that their research dealt with not one but a “whole sweep of tilings” interpreted through a few hundred examples.
The article quoted two other experts, Dov Levine and Joshua Socolar, physicists at the Israel Institute of Technology in Haifa and Duke University, respectively, as agreeing that Dr. Makovicky deserved more credit. But, the article noted, they said the Lu-Steinhardt research had “generated interesting and testable hypotheses.”
Spacecraft Closes In for a Look at Jupiter, With Pluto Next on the List
By WARREN E. LEARY, The New York Times, February 27, 2007
WASHINGTON, Feb. 26 — The New Horizons spacecraft, launched from Earth by NASA some 13 months ago, is moving in for a close encounter with Jupiter on Wednesday that should let it test its suite of instruments before being flung off toward the distant target of Pluto and its trio of moons.
The half-ton, atomic-powered robot craft is to make more than 700 observations of Jupiter and its four largest moons by June. A period of high-intensity observations began last Saturday and will peak after the craft makes its closest approach to Jupiter on Wednesday, passing 1.4 million miles from the center of the giant planet.
Jupiter’s gravity will accelerate the spacecraft by 9,000 miles per hour, flinging it toward Pluto at 52,000 miles per hour. Even with the speed boost, which knocks off three years of travel time, New Horizons will take eight more years to reach the Pluto system for a close-up look in July 2015, when Pluto will be 3 billion miles from Earth, a distance requiring almost four and a half hours for a radio signal to pass between them.
“Our highest priority is to get the spacecraft safely through the gravity assist and on its way to Pluto,” said Alan Stern of the Southwest Research Institute in Boulder, Colo., the mission’s principal scientist and team leader. “But this is also a big stress test for our primary mission to Pluto. We want to exercise our spacecraft hard enough to turn up any problems and to fully test our procedures.”
New Horizons is powered by a small plutonium-fueled electric generator, and its instruments include three cameras, for visible-light, infrared and ultraviolet images, a space-dust collector and three spectrometers to study the chemical composition and temperatures of the worlds it investigates.
John Spencer, a mission scientist who is also from the Southwest Research Institute, said New Horizons carried more advanced instruments than any of the seven spacecraft that previously visited Jupiter and would be making unique observations. “We will not be repeating what has already been done,” he said.
Scientists plan for the spacecraft to make three-dimensional movies of the turbulent area near Jupiter’s famous Great Red Spot, a centuries-old giant hurricane; examine auroras above the atmosphere in different wavelengths of light; and make the first edge-on observations of the planet’s tenuous ring system in hopes of finding some tiny satellites there, Dr. Spencer said.
The spacecraft will also make a major study of Jupiter’s enormous magnetosphere, a cocoon of charged particles from the Sun that are trapped and channeled around the planet by its magnetic field. In the months after the Jupiter fly-by, plans call for New Horizons to make the first trip down the magnetosphere’s long tail of high-energy particles that extend tens of millions of miles beyond the planet.
Much of the data collected during the Jupiter encounter will be recorded aboard the spacecraft and sent back to Earth days or weeks later, just as New Horizons is scheduled to do when it makes its closest pass by Pluto, its large moon Charon and the smaller satellites Nix and Hydra on July 14, 2015.
Months after the Jupiter encounter, the $700 million project will go to sleep for much of the cruise period to Pluto. New Horizons will be put into a “hibernation mode” with most of its systems and instruments turned off to reduce wear and tear and to save power. Operators are to wake the spacecraft once a year during the long journey to check its status and correct its flight path.
Christopher Peterson of the Glen Canyon Institute in the Escalante River in Utah. A high-water mark remains, halfway up the rock wall.
That ‘Drought’ in Southwest May Be Normal, Report Says
By CORNELIA DEAN, The New York Times, February 22, 2007
The Colorado River Basin is more prone to drought than had been thought, a panel of experts reported yesterday, and as the climate warms and the population in the region grows, pressure on water supplies will become greater.
The severe droughts the region suffered in the 1990s and early 2000s would not stand out in the record of the last few centuries, the panel said, and the future presents “a sobering prospect for elected officials and water managers.” The panel said residents of the region should prepare for more frequent and more severe dry spells, and “costly, controversial and unavoidable trade-offs” in water use.
The data discussed in the report have been published before in scholarly journals and elsewhere. But Ernest T. Smerdon, a former dean of the College of Engineering and Mines at the University of Arizona, who led the panel, said its members hoped with this publication to pull the findings into a single document that ordinary people could understand.
Severe droughts will recur, Dr. Smerdon said, “and we better be prepared. That is the message.” He spoke at a news conference yesterday in Las Vegas, where the report was made public.
The panel recommended an “action-oriented” study of water use patterns and demands, including drought planning, population projections and possible effects of transferring water to urban areas from agriculture, still the dominant consumer. Dialogue between policy makers and scientists who study water issues should be “a permanent fixture within the basin,” it said.
The panel, organized by the National Research Council, the research arm of the National Academy of Science, noted that the water allocation agreement for the basin, the Colorado River Compact, was negotiated in 1922 based on river flow records dating to the 1890s, when gauging stations were established. The agreement assumed that the annual river flow was 16.4 million acre feet — enough to cover 16.4 million acres to a depth of one foot.
But for some time, the panel said, researchers have known that the early 20th century was unusually wet and that 15 million acre feet was a more accurate estimate of the flow. Recent studies based on tree rings put the figure lower still — as low as 13 million acre feet — and suggest that “drought episodes are a recurrent and integral feature of the region’s climate.”
Because trees grow more when it is wet, scientists use tree ring size as an indicator of water abundance. The report says the federal Bureau of Reclamation and other agencies requested the panel’s review in the wake of the new findings.
Global warming is already making things worse, the experts said. For one thing, warmer weather means less precipitation in the form of snow, which is stored in the region’s mountain snowpack. And the snowpack itself forms later and melts sooner each winter. As a result, the steady reliability of snowpack water storage is compromised. Also, warmer weather itself increases consumer, environmental and agricultural demands for water.
Rainfall patterns are difficult to predict, another panel member, Connie A. Woodhouse, a geographer at the University of Arizona, said at the news conference. But the report said it was probable that the region would experience less precipitation over all in a warmer world.
Cloud-seeding, water desalinization and improved underground water storage have yet to emerge as solutions, the report said, and even conservation, while helpful, “is no panacea,” Dr. Smerdon said.
The report, which is available at www.nationalacademies.org, notes that the basin, 240,000 square miles in Wyoming, Utah, Colorado, New Mexico, Arizona, Nevada, California and Mexico, has seen rapid population growth in recent decades. Until about 30 years ago, the panel wrote, growing demands for water were met through building dams and reservoirs. But today, the report says, “prospects for constructing additional large dams in the Colorado River basin have diminished.”
Instead, “there is going to have to be some kind of reallocation of who gets the water,” said Richard Seager, a climate expert at the Lamont Doherty Earth Observatory, who was not involved in the panel’s report.
Dr. Seager, who studies the drought history of North America, said that it was “silly” to put golf courses in the region’s desert areas and that hotels and other businesses were already installing water-conserving toilets and other fixtures.
But he added, referring to cattle and cotton raising, “Let’s think whether it makes sense to have all this subsidized agriculture in the region, people who aren’t even paying the full cost of the water they do use.”
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drought
Date: 2007-02-27 05:41 pm (UTC)Even Moab has a golf course and a water park. And it's growing too. There's two new subdivisions I can see from my house out here in the boonies. I think we actually get very little of our water from the river (which is good considering the huge uranium tailings superfund site right on the banks) but there have been very few studies of what the aquifers are actually like around here. I think the snowpack in the LaSals is only at 60% of normal right now.
no subject
Date: 2007-03-02 06:32 pm (UTC)