Sun-Earth Relationship

The Sun is our nearest star. Nuclear reactions deep inside the Sun create the light and heat we need for our survival. Scientists think the Sun was born about five billion years ago. Although the Sun is consuming four million tonnes of hydrogen fuel every second, it is so large that it should continue to shine for another five billion years. By that time, it will have swollen into a red giant, causing the oceans to boil away and destroying all life on our planet.

The Sun's activity varies over an 11-year period. The number of sunspots and flares, and the radiation output, change over time. The most recent peak in its cycle of activity occurred in mid-2000 with a second peak at the end of 2001. Scientists are hoping that the two missions in ESA's Solar-Terrestrial Programme, SOHO and Cluster, will be able to tell them more about how the Sun works and how it affects the Earth. While SOHO studies explosions on the Sun and detects solar storms heading our way, Cluster will measure the effects of this activity on near-Earth space as the incoming energetic particles subject the magnetosphere to a buffeting.

The Sun as seen by SOHO on 14 September 1997 in extreme ultraviolet light.
The solar prominence, bottom left, has a temperature of some 70 000 °C.
The solar corona is hotter than a million degrees Celsius

Facts about the Sun

Distance From Earth	149 600 000 km
Diameter	1 392 000 km (= 109 Earth diameters)
Rotation Period at Equator	24.6 days
Surface Temperature	5500 oC
Core Temperature	15 million oC
Mass (Earth = 1)	333 000
Volume (Earth = 1)	1 300 000
Gravity (Earth = 1)	27.94

How the Sun affects our planet

The Sun affects our world in many ways. A continuous stream of atomic particles - the solar wind - pours out into space from the Sun at speeds ranging from 300 to 1000 kilometres per second (1800 times faster than Concorde!). Sometimes, explosions on the Sun send millions of tonnes of gas towards the Earth. These clouds of high energy particles can cross the 150 million kilometre gulf between the Sun and Earth in a few days. The most energetic particles of all, created by solar flares, can reach Earth in just 30 minutes.

An aurora: a product of charged particles radiated by the Sun interacting with the Earth's atmosphere	A solar Coronal Mass Ejection (CME) event as recorded by SOHO on 2 June 1998

When charged particles from the Sun enter Earth's upper atmosphere, they create shimmering curtains of coloured light, known as auroras, in the polar night sky. Other effects can be much more serious:

• Solar storms affect Earth's ionosphere, causing disruption of short wave radio communications, navigation systems on ships and aircraft, and military radar systems
  
• Surges in long electricity transmission lines may cause power and widespread blackouts, as happened in Quebec, Canada, in March 1989 when 6 million people were left without electricity due to a huge solar-induced magnetic storm
  
• Damage to microchips and electrical discharges may cause satellites to stop operating, causing disruption of, for example, telephone, TV and data communication services
  
• Radiation levels can become hazardous to astronauts and occupants of high flying aircraft
  
• High energy particles hitting Earth's upper atmosphere can destroy the ozone layer, which protects us from harmful ultraviolet radiation
  
• Solar storms have even been blamed for increased corrosion in oil pipelines
  
• Solar energy output varies over the 11-year sunspot cycle. This may cause climate changes, which can affect vegetation growth and food supplies
  

source : http://sci.esa.int

Looking for Other Earths Heats Up

The ESA's COROT mission is the most advanced Earth-finder around, and could hit the jackpot by 2010.

by bStephen Ornes

So you want to go looking for other Earth-like planets and the universe is big. How do you start? Where do you look? “You select areas where you have a lot of solar-type stars,” says Malcolm Fridlund, a project scientist for the European Space Agency (ESA). “They’re most likely to have planets like our solar system’s.” Fridlund helped design COROT (for convection, rotation, and planetary transits), ESA’s early entry in the race to find rocky, Earth-like planets outside our solar system.

Launched late last year, COROT is collecting information about distant planets as well as measuring cosmic stellar vibrations, which provide clues to the interiors of distant stars. In late April, the satellite is scheduled to execute a slow, steady about-face to look the center of the Milky Way straight in the eye and scan the dense crowds of stars there for terrestrial planets. “COROT is like a fisherman who has a giant net and catches fish from time to time,” says Laurent Kerjean, who runs COROT’s system tests.

Over 150 days this summer, COROT will capture data from an area of sky roughly equal to the size of the constellation Orion. Then it will turn and continue its hunt in the opposite direction. By the end of COROT’s mission, which could last up to three years, investigators expect to have searched for rocky planets around 50,000 to 60,000 stars, providing the first good stats on the abundance of such worlds.

COROT is the first—and at $175 million, the cheapest—planet-seeking mission to get off the ground. NASA’s first Earth seeker, the Kepler mission, is scheduled for liftoff in 2009, and both NASA and ESA have scheduled more sophisticated missions for the next two decades. “We don’t know how common Earth-like planets are in our big universe. They could be extremely rare,” Fridlund says. On the other hand, “if COROT picks up rocky planets, then that means that Earth-like planets are common in the galaxy and that the conditions under which life could arise might not be that rare.”

The satellite contains a 10.6 inch telescope
and an array of spectroscopic detectors to
seek out rocky, Earth-like planets with the
potential for habitability beyond our solar
system.

(Courtesy of ESA)

Satellites map subtle variations in Earth’s gravitational field (3 of 3)

Grace in Space

A pair of satellites map subtle variations in Earth’s gravitational field, revealing secret craters, undersea mountains, and the impact of climate change.

by Sam Flamsteed

GRACE’s data are open to any scientist on the planet. “That,” says Byron Tapley, “led to a whole range of people outside the standard community who used GRACE results to do things that weren’t possible before.” In January 2005, for example, Ohio State University geophysicist Ralph von Frese and his colleagues noticed a concentration of higher-than-average-density material in the rock about a mile under the surface of the East Antarctic ice sheet. Mass concentrations like this often accumulate when giant impacts from space pound the crust. When the crust rebounds, it carries higher-density mantle materials up toward the surface and holds them there. Comparing the GRACE data with radar imagery of the icebound bedrock, von Frese found it was centered perfectly inside a ring some 300 miles wide—just what you’d expect from an impactor 30 or so miles across. “It just jumped out at us,” he says.

An asteroid that big would be about four to five times the diameter of the object that killed off the dinosaurs 65 million years ago. This crater is much older, arguably dating back to a time, some 250 million years ago, when something—perhaps a projectile from outer space—wiped out the majority of the species on Earth, including most reptiles, sponges, corals, starfish, clams, sea scorpions, and fish, thereby clearing the evolutionary decks for dinosaurs to become dominant. That was the greatest mass extinction in history, and thanks to GRACE, paleontologists and evolutionary biologists now have an idea of how it may have happened.

But GRACE’s greatest contribution comes from the fact that it remeasures the geoid every month or so. That enabled geologists to make before-and-after assessments of how the seafloor rearranged itself in the Sumatra-Andaman earthquake of December 26, 2004, which triggered the awful Indian Ocean tsunami. “When a major quake happens on land,” Watkins says, “you can go out and look at the changes. With GRACE, we can now look thousands of feet underwater as well.”

A gravity map of the world: Larger lumps and
red shading indicate regions of greatest
mass, and hence gravitational pull.

The satellites can also reveal movement of water itself, in ways never possible before. “It’s very cool, because water can go underground, it can move around the ocean, it can change from ice to liquid and runoff, but it can’t hide its mass from us,” says Watkins. Imagine, he says, a gigantic hockey puck made of water. “It could be in the form of an ice sheet, or an aquifer, or a piece of ocean. GRACE has the sensitivity to pick up a puck about a centimeter thick and 400 kilometers [half an inch and 250 miles] across.” All the water on Earth can be divided into hockey pucks, he says, and GRACE takes note of how they move around every 30 days.

Last March, geophysicists Isabella Velicogna and John Wahr at the University of Colorado at Boulder published a paper in Science Express that used GRACE data to show that the ice sheet covering Antarctica has shrunk by an average of 36 cubic miles of ice per year—surprising, given that many climate models predict a thickening of the ice as higher global temperatures lead to more evaporation and precipitation. “It’s very difficult for models to reproduce the physics of glaciers, and this shows that the models aren’t as good as we’d like them to be,” Velicogna says.

(Click here to enlarge.)
Grace captured images of Greenland each month in
2005 from January (top left) through December (bottom
right), revealing a giant loss of ice mass (dark blue and
purple).

Velicogna and her colleagues also measured a dramatic loss of Greenland ice, as much as 38 cubic miles per year between 2002 and 2005—even more troubling, given that an influx of fresh meltwater into the salty North Atlantic could in theory shut off the system of ocean currents that keep Europe relatively warm. (A separate group at the University of Texas published figures extrapolated from GRACE data showing that Greenland lost as much as 57 cubic miles of ice each year between 2002 and 2005; NASA shortly plans to publish data reconciling the two studies.) “It’s a wake-up call,” says Velicogna, “because there is a lot of water that can go from the ice sheets into the ocean. Both ice sheets are significantly losing mass, and that affects sea level. If sea level is going to rise, that will affect a lot of coastal areas.”

This past December an entire session of the American Geophysical Union’s fall meeting was devoted to movement of water in and out of giant watersheds all over the world. Speakers presented eight papers, on topics ranging from the hydrologic impact of the Three Gorges Dam in China to the impact of climate change on Siberian river systems. All the new findings were based entirely on data from GRACE. Notable results included a report from researchers at MIT that Alaska lost an average of 10 and a half cubic miles of ice each year from 2003 to 2005.

Oceanographers, geologists, and climatologists are scrambling to update their models of the planet based on the flood of GRACE data. But these will start to look positively primitive when a new, upgraded version of GRACE comes along in several years. Armed with laser interferometers more sensitive than the microwave type, GRACE scientists will be able to attain much better resolution, and thus to find even subtler gravity variations and more exquisite detail, or “smaller hockey pucks,” in Watkins’s words. Nevil Maskelyne never managed to make his own experiment work, but with GRACE his idea has been vindicated beyond even his wildest imaginings.

Satellites map subtle variations in Earth’s gravitational field (2)

Grace in Space

A pair of satellites map subtle variations in Earth’s gravitational field, revealing secret craters, undersea mountains, and the impact of climate change.

by Sam Flamsteed

Unfortunately, the variation in distance between the two satellites is so small that in the early 1960s it would have been virtually impossible to detect using any technology then available. In 1976 NASA launched a satellite called LAGEOS (Laser Geodynamics Satellite), which began to address the problem, albeit crudely. It carried no instruments at all. In essence, LAGEOS was a two-foot-diameter shiny brass golf ball; by bouncing laser beams off the satellite from different places on the surface of Earth, geologists could measure the precise distances between widely separated places on the planet. They could, for example, see the gradual separation of continents, due to plate tectonics, year by year.

In the early 1990s the TOPEX (Topography Experiment for Ocean Circulation)/Poseidon satellite, a joint American-French mission, shot into orbit armed with radar altimeters to measure the height of the sea surface. “What they’ve basically done,” Watkins says, “is to look at changes in the sea surface over time, on the assumption the geoid itself doesn’t change.” Except that sometimes it does. Along with its measurements of continental drift, LAGEOS also detected a very gradual change in the gravity field over Canada and northern Europe as the crust continues to rebound—10,000 years later—from the weight of the massive glaciers that pinned it down during the last ice age. It also revealed annual variations in local gravity due to the natural storage and depletion of water during rainy and dry seasons in different parts of the world.

Laser beams fired at LAGEOS were not sensitive enough to pinpoint variations in orbit smaller than a centimeter or so and were too imprecise to pick out the subtler differences in gravity. For that, a double-satellite mission was needed. Finally, in the mid-1990s, the technology to pull it off became available in two forms. The first was microwave transmitters and receivers small, efficient, and reliable enough to be to mounted on small spacecraft and used to gauge the distance between the satellites. The second: the Global Positioning System (GPS). “If I’m sending a signal from me to you,” says Watkins, “and I want to know the time of flight, it’s crucial that our clocks be perfectly synchronized.” By checking in constantly with whatever GPS satellite is in view at a given time, a pair of gravity satellites can use its single clock rather than trying to synchronize their own.

With the technology finally in place, Watkins, together with ­aerospace engineer Byron Tapley of the University of Texas at Austin and several other scientists and engineers, proposed the GRACE mission. In partnership with the German space agency, NASA sent the dual GRACE satellites into orbit in March 2002. Since then, they have been zipping around Earth in a polar orbit, one satellite about 137 miles ahead of the other. To an observer in space, they would appear to be tracing out the same circle over and over, but since the planet is continuously rotating beneath them, the intrepid satellites orbit over every slice of the surface once every 30 days.

GRACE’s data show that the ice sheet covering Antarctica has lost an average of 36 cubic miles of ice per year

Their instruments measure not the distance between the two satellites but rather the change in distance, and thus the acceleration due to gravity. They do it through interferometry—watching how beams of microwaves interfere with each other. One satellite shoots out a continuous stream of microwaves, which is received by the second satellite and both are sent to the ground. The outgoing and incoming beams are superimposed, creating an interference pattern that varies depending on how close the waves are to being perfectly in phase—that is, how close the waves’ peaks and valleys are lined up. A tiny difference in satellite-to-satellite distance—and thus an increase or decrease in gravitational pull from Earth’s surface—makes a marked difference in the interference pattern. If the satellites are moving together or apart at as little as 150 nanometers per second, the GRACE scientists can see it.

(Click here for a larger version.)

A map of gravity anomalies created by GRACE shows
mountain ranges and other large masses in red—
even those under the sea.

That is not quite the end of the story. Even though 310 miles up is technically outer space, a few air molecules still float around—not enough to make the slightest difference to astronauts on a space shuttle or the space station, which orbit considerably lower, but sufficient to slow the GRACE satellites perceptibly. A clump of air molecules could fool an observer into thinking that something lies below—perhaps a glacier—so each satellite has what’s known as a “proof mass” floating in a chamber inside, untethered to the satellite itself. The proof mass is itself in orbit, so when one of the satellites speeds up or slows down due to gravity variations, the mass does too. But when a satellite slows due to air drag, the proof mass inside, blissfully unaware, keeps moving at its original speed. It doesn’t hit the interior wall of the satellite because onboard electric plates keep it from doing so—but sensitive electronics keep track of the discrepancy so the engineers can subtract it from the real signal.

Satellites map subtle variations in Earth’s gravitational field (1)

Grace in Space

A pair of satellites map subtle variations in Earth’s gravitational field, revealing secret craters, undersea mountains, and the impact of climate change.

by Sam Flamsteed

If the Reverend Nevil Maskelyne came back to life, the 18th-century Astronomer Royal of Great Britain would probably have no trouble grasping the idea behind NASA’s remote sensing GRACE mission. Maskelyne proposed a remarkably similar experiment himself in a presentation to the Royal Society in 1772. “If the attraction of gravity be exerted, as Sir Isaac Newton supposes, not only between the large bodies of the universe, but between the minutest particles of which these bodies are composed . . . it will necessarily follow, that every hill must, by its attraction, alter the direction of gravitation in heavy bodies in its neighbourhood . . . .”

That’s exactly what GRACE, the Gravity Recovery and Climate Experiment, detects. Every 94 minutes or so, twin satellites whip once around Earth at an altitude of 310 miles, taking 30 days to cover the planet’s entire surface, then they do it again and again, sensing variations in local gravity. GRACE maps local variations in the force of gravity over Earth’s surface, revealing mountain ranges and ocean trenches as well as underground watersheds and other hidden concentrations of mass. A joint venture by NASA and the DLR (Deutsches Zentrum für Luft- und Raumfahrt, or German Aerospace Center), GRACE looks right past the familiar oceans, continents, and clouds, showing our planet in a fresh light—as a knobby, blobby globe of gravitational ups and downs.

(Click Here to enlarge.)
A gravity map of the world: Larger lumps and
red shading indicate regions of greatest
mass, and hence gravitational pull.

Among other things, GRACE may have found a crater deep under the Antarctic ice that may mark an asteroid impact greater than the one that doomed the dinosaurs, measured the seafloor displacement that triggered the tsunami of 2004, and quantified changes in subsurface water in the Amazon and Congo river basins. “This is really an entirely new kind of remote sensing,” says project scientist Michael Watkins, of NASA’s Jet Propulsion Laboratory. “It’s like when radar or photography was first invented—you start realizing that it can be applied in all sorts of unanticipated ways. We’re still discovering them.”

The notion that Earth’s gravity field could be measured with satellites dates back to the dawn of the space age. In 1958 ground controllers tracking the first American satellite, Explorer 1, noted that its path faithfully traced the planet’s equatorial bulge (created by centrifugal forces generated by the planet’s rotation). By the 1960s rocket scientists realized that smaller, local variations in gravity could have further, unforeseen effects. Missiles carrying nuclear warheads, for example, could be thrown off course if no allowance was made for mountain ranges or valleys.

If Earth were a perfect sphere, perfectly uniform in density and covered to a uniform depth with ocean, the geoid—a word coined by geologists to refer to an imaginary plane located at the average level of the sea’s surface—would be a perfect sphere as well. Since the geoid would be evenly perpendicular to the pull of gravity in all places, that force would always pull you directly toward the precise center of the Earth. But Earth is nowhere near perfect or uniform, which means that gravity doesn’t always point straight down; a mountain range, for example, might divert it slightly to the left.

Understanding the subtleties of Earth’s gravitational field would be useful in many ways. Scientists could learn a lot about the structure of the planet, what it’s made of, and where the crust is thick or thin. A deposit of high-density underground rock, or an undersea mountain, is utterly invisible—yet they, too, skew the geoid away from perfect flatness. Even when the ocean is utterly calm, it isn’t flat. Measurements reveal that some parts of the ocean are a remarkable 390 feet lower than average, and others are 300 feet higher.

(Click here to enlarge.)
Maps of South America, created from GRACE readings
taken in 2003, show how water storage in the Amazon
and Orinoco basins increases and decreases with
seasonal changes in rainfall. Red indicates greater
gravitational force, and hence higher water storage;
blue reveals that less water is present.

While scientists began to appreciate just how useful a map of the geoid could be, engineers were realizing that the most sensible way to measure the variations would be with a pair of satellites, instead of just one. A single orbiter would bob and weave with the gravity field just fine—but monitors would have to measure the ups and downs from the ground continuously by beaming radio waves back and forth. That would require an enormous network of ground stations. Yet two satellites flying far enough apart would experience different gravitational effects, so that only the distance between them must be measured. As the lead satellite approaches a place with more mass than average, it speeds up just a bit from the extra gravitational pull. Shortly thereafter, so does the second. Then, as the higher-mass region falls behind, each satellite is held back a little—again, first the leading, then the trailing satellite. By sending microwaves between the two, it would be possible to calculate that staggered acceleration, and thus infer the change in gravitational pull on Earth’s surface.

TEMPORAL MAPPING AND ANALYSIS

Title:

TEMPORAL MAPPING AND ANALYSIS

Document Type and Number:

United States Patent 20060276968         Kind Code: A1

Abstract:

A compositing process comprises selecting a spatial data collected over a period of time, creating temporal data cubes from the spatial data, and processing and/or analyzing the data using temporal mapping algebra functions. In some embodiments, the temporal data cube is creating a masked cube using the data cubes, and computing a composite from the masked cube by using temporal mapping algebra.

Link to this page:

http://www.freepatentsonline.com

Astronomers Map Out Planetary Danger Zone

Source : NASA/Jet Propulsion Laboratory  -  ScienceDaily

VariousSoftware-Astronomers have laid down the cosmic equivalent of yellow "caution" tape around super hot stars, marking the zones where cooler stars are in danger of having their developing planets blasted away.

In a new study from NASA's Spitzer Space Telescope, scientists report the first maps of so-called planetary "danger zones." These are areas where winds and radiation from super hot stars can strip other young, cooler stars like our sun of their planet-forming materials. The results show that cooler stars are safe as long as they lie beyond about 1.6 light-years, or nearly 10 trillion miles, of any hot stars. But cooler stars inside the zone are likely to see their potential planets boiled off into space.

An infrared view of the Rosette nebula, with danger zones highlighted. (Credit: NASA/JPL-Caltech/Univ.of Ariz.)

"Stars move around all the time, so if one wanders into the danger zone and stays for too long, it will probably never be able to form planets," said Zoltan Balog of the University of Arizona, Tucson, lead author of the new report, appearing May 20 in the Astrophysical Journal.

The findings are helping astronomers pinpoint the types of environments where planets beyond our solar system, including some that might be hospitable to life, are most likely to form.

Planets are born out of a flat disk of gas and dust, called a protoplanetary disk, that swirls around a young star. They are believed to clump together out of the disk over millions of years, growing in size like dust bunnies as they sweep through the dust.

Previous studies revealed that these protoplanetary disks can be destroyed by the most massive, hottest type of star in the universe, called an O-star, over a period of about a million years. Ultraviolet radiation from an O-star heats and evaporates the dust and gas in the disk, then winds from the star blow the material away. Last year, Balog and his team used Spitzer to capture a stunning picture of this "photoevaporation" process at work.

The team's new study is the first systematic survey for disks in and around the danger zone, or "blast radius" of an O-star. They used Spitzer's heat-seeking infrared eyes to look for disks around 1,000 stars in the Rosette Nebula, a turbulent star-forming region 5,200 light-years away in the constellation Monoceros. The stars range between one-tenth and five times the mass of the sun and are between 2 and 3 million years old. They are all near at least one of the region's massive O-stars.

The observations revealed that, beyond 10 trillion miles of an O-star, about 45 percent of the stars had disks - about the same amount as there were in safer neighborhoods free of O-stars. Within this distance, only 27 percent of the stars had disks, with fewer and fewer disks spotted around stars closest to the O-star. In other words, an O-star's danger zone is a sphere whose damaging effects are worst at the core. For reference, our sun's closest star, a small star called Proxima Centauri, is nearly 30 trillion miles away.

In addition, the new study indicates that a protoplanetary disk will boil off faster in the zone's perilous core. For example, a disk two times closer to an O-star than another disk will evaporate twice as fast. "The edges of the danger zone are sharply defined," said Balog. "It is relatively safe for protoplanetary disks outside it, whereas a disk that gets dragged along by its star to be really close to an O-star could disappear in as fast as a hundred thousand years."

Despite this doomsday scenario, there is a chance some planets could survive a close encounter with an O-star. According to one alternative theory of planet formation, some gas giants like Jupiter might form in less than one million years. If such a planet already existed around a young star whose disk is blown away, the gas giant would stay put while any burgeoning rocky planets like Earth would be forever swept away.

Some astronomers think our sun was born in a similarly violent neighborhood studded with O-stars before migrating to its present, more spacious home. If so, it was lucky enough to escape a harrowing ride into any danger zones, or our planets, and life as we know it, wouldn't be here today.

Other paper authors include James Muzerolle, Kate Su, George Rieke and Erick Young of the University of Arizona; and Tom Megeath of the University of Toledo, Ohio.

NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, also in Pasadena. Caltech manages JPL for NASA. Spitzer's multiband imaging photometer, which collected the new data, was built by Ball Aerospace Corporation, Boulder, Colo.; the University of Arizona; and Boeing North American, Canoga Park, Calif. Co-author Rieke is the instrument's principal investigator.

Note: This story has been adapted from a news release issued by NASA/Jet Propulsion Laboratory.

New Satellite Coverage In South America To Limit Effects Of Natural Disasters

South Americans, and millions more in the Western Hemisphere, are benefitting from the reposition of NOAA's GOES-10 spacecraft, a move designed to lessen the effects of natural disasters in the region. The satellite's successful shift from a position above the equator in the West, to a new spot in orbit, was recently announced.

"Repositioning GOES-10 provides a constant vigil over atmospheric conditions that trigger severe weather, and I am pleased that the United States can strengthen the quality and quantity of data available to our Latin American partners," said retired Navy Vice Admiral Conrad C. Lautenbacher, Ph.D., undersecretary of commerce for oceans and atmosphere and NOAA administrator.

Shifting GOES-10 is part of the emerging GEOSS in the Americas, a Western Hemisphere initiative designed to advance the Global Earth Observation System of Systems, or GEOSS. Through this endeavor, NOAA is exploring partnerships with countries and scientific organizations in the Americas and Caribbean to share Earth observations and develop and strengthen data networks. Western Hemisphere nations will work together to ensure the satellite data are disseminated and training is available to enable full use of the new information.

"The satellite is functioning well and ready for hurricane season," said Gilberto Câmara, Ph.D., director of Brazil's National Space Research Institute (Instituto Nacional de Pesquisas Espaciais). "In the past, coverage has been interrupted during hurricanes and other severe weather events in the U.S. Now, South Americans will have continuing satellite coverage. We will no longer be left in the dark."

NOAA's GOES satellites orbit Earth's equator at a speed matching the planet's rotation, allowing them to hover over one position. They provide scientists with detailed weather measurements and frequent imagery used to develop short-term forecasts that help protect life and livelihoods. In South America, the new satellite coverage is already having an impact. On March 8, for instance, Argentina was able to trace a low pressure development and then accurately issue a high-rainfall alert that helped save lives in Buenos Aires and other highly-populated areas. The new coverage also is contributing to improved fire detection in the Amazon rainforest of western Brazil.

In addition, GOES-10 is providing South America with images of the Earth's atmosphere system twice as frequently as before. South America now receives coverage nearly as far south as the South Pole, with images every 15 minutes. History has proven that there is a vital need for the advanced warning this additional information may provide. During the1990s in South America, natural disasters caused nearly 70,000 deaths, and more than half were from flooding. Storms, cyclones, hurricanes and mudslides caused another 20 percent of the deaths. In May 2003, the largest flooding in 500 years hit Argentina's north-central region, displacing more than 100,000 people and causing $1 billion in damage.

In the Western Hemisphere, nine countries are working with global partners to build GEOSS, including Argentina, Brazil, Belize, Canada, Chile, Honduras, Mexico, Paraguay and the United States. More countries are expected to begin participating later this year. In the U.S., 15 federal agencies and three White House offices are engaged in developing the U.S. component of GEOSS. The goal of the integrated system of systems is to provide comprehensive, coordinated and sustained Earth observations from thousands of instruments worldwide, transforming the data they collect into a range of societal benefits spanning global public health, energy, agriculture and weather and climate, among others.