Active Mercury

	04.30.2009
April 30, 2009: A NASA spacecraft gliding over the surface of Mercury has revealed that the planet's atmosphere, magnetosphere, and its geological past display greater levels of activity than scientists first suspected. The probe also discovered a large impact basin named "Rembrandt" measuring about 430 miles in diameter. These new findings and more are reported in four papers published in the May 1 issue of Science magazine. The data come from the Mercury Surface, Space Environment, Geochemistry, and Ranging spacecraft--MESSENGER for short. On Oct. 6, 2008, MESSENGER flew by Mercury for the second time, capturing more than 1,200 high-resolution and color images of the planet. Right: The Rembrandt impact basin discovered by MESSENGER during its second flyby of Mercury in October 2008. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Smithsonian Institution/Carnegie Institution of Washington. [more] "This second Mercury flyby provided a number of new findings," said Sean Solomon, the probe's principal investigator from the Carnegie Institution of Washington. "One of the biggest surprises was how strongly [Mercury's magnetosphere] had changed from what we saw during the first flyby in January 2008." Sign up for EXPRESS SCIENCE NEWS delivery The magnetosphere is a region of space around Mercury enveloped by the planet's magnetic field. Gusty solar wind buffeting the global bubble of magnetism can potentially trigger magnetic storms and other space weather-related phenomena. "During the first flyby, MESSENGER measured relatively calm dipole-like magnetic fields close to the planet. Scientists didn't detect any dynamic features other than some Kelvin-Helmholtz waves," said James Slavin of NASA's Goddard Space Flight Center. Slavin is a mission co-investigator and lead author of one of the papers. "But the second flyby was a totally different situation," he says. MESSENGER observed a highly dynamic magnetosphere with "magnetic reconnection" events taking place at a rate 10 times greater than what is observed at Earth during its most active intervals. "The high rate of solar wind energy input was evident in the great amplitude of the plasma waves and the large magnetic structures measured by the spacecraft's magnetometer throughout the encounter." Above: An artist's concept of Mercury's surprisingly active magnetosphere. Credits: Image produced by NASA/Goddard Space Flight Center/Johns Hopkins University Applied Physics Laboratory//Carnegie Institution of Washington. Image reproduced courtesy of Science/AAAS. [more] Another exciting result is the discovery of a previously unknown large impact basin. The Rembrandt basin is more than 700 kilometers (430 miles) in diameter and if formed on the east coast of the United States would span the distance between Washington, D.C., and Boston. Rembrandt formed about 3.9 billion years ago, near the end of the period of heavy bombardment of the inner Solar System, suggests MESSENGER Participating Scientist Thomas Watters, lead author of another of the papers. Rembrandt is significant, not only because it is big, but also because it is giving researchers a peek beneath the surface of Mercury that other basins have not. "This is the first time we've seen terrain exposed on the floor of an impact basin on Mercury that is preserved from when it formed," explains Watters. "Landforms such as those revealed on the floor of Rembrandt are usually completely buried by volcanic flows." Half of Mercury was unknown until a little more than a year ago. Globes of the planet were blank on one side. Spacecraft images have since revealed 90 percent of the planet's surface at high resolution. This near-global coverage is showing, for the first time, how Mercury's crust was formed. Right: In this interpretive map of Mercury's surface, shades of yellow denote smooth plains of mainly volcanic origin. This type of terrain covers approximately 40% of the planet. The white (empty) slice is the portion of Mercury not yet photographed. Credit: NASA/Johns Hopkins University Applied Physics Laboratory/Arizona State University/Carnegie Institution of Washington. [more] "After mapping the surface, we see that approximately 40 percent is covered by smooth plains," said Brett Denevi of Arizona State University in Tempe, a team member and lead author of a paper. "Many of these smooth plains are interpreted to be of volcanic origin, and they are globally distributed. Much of Mercury's crust may have formed through repeated volcanic eruptions in a manner more similar to the crust of Mars than to that of the moon." Another finding of the flyby is the first detection of magnesium in Mercury's exosphere. The exosphere is an ultrathin atmosphere where the molecules are so far apart they are more likely to collide with the surface than with each other. Material in the exosphere comes mainly from the surface of Mercury itself, knocked aloft by solar radiation, solar wind bombardment and meteoroid vaporization: The probe's Mercury Atmospheric and Surface Composition Spectrometer instrument detected the magnesium. Finding magnesium was not surprising to scientists, but the abundance was unexpected. The instrument also measured other exospheric constituents including calcium and sodium. Researchers believe that big day-to-day changes in Mercury's thin atmosphere may be caused by the variable shielding of Mercury's active magnetosphere. "This is an example of the kind of individual discoveries that the science team will piece together to give us a new picture of how the planet formed and evolved," said William McClintock of the Laboratory for Atmospheric and Space Physics at the University of Colorado at Boulder. McClintock is co-investigator and lead author of one of the four papers. "The third Mercury flyby [coming up on Sept. 29th] is our final dress rehearsal for the main performance of our mission, the insertion of the probe into orbit around Mercury in March 2011," said Solomon. "The orbital phase will be like staging two flybys per day and will provide continuous collection of information about the planet and its environment for one year." "Mercury has been coy in revealing its secrets slowly so far, but in less than two years the innermost planet will become a close friend." Source:NASA

Space Shuttle Atlantis Launches on Final Mission to Hubble

May 11, 2009: Space shuttle Atlantis with its seven-member crew launched at 2:01 p.m. EDT on Monday, May 11, from NASA's Kennedy Space Center on the final Hubble Space Telescope servicing mission. Atlantis' 11-day mission will include five spacewalks to refurbish Hubble with state-of-the-art science instruments designed to improve the telescope's discovery capabilities by up to 70 times while extending its lifetime through at least 2014. Shortly before liftoff, Commander Scott Altman thanked the teams that helped make the launch possible. "At last our launch has come along," said Altman. "...Getting to this point has been challenging, but the whole team, everyone, has pulled together to take us into space." Above: Space shuttle Atlantis lifts off Launch Pad 39A at NASA's Kennedy Space Center in Florida, beginning the STS-125 mission to service the Hubble Space Telescope. Photo credit: NASA Television Altman is joined on STS-125 by Pilot Gregory C. Johnson and Mission Specialists Megan McArthur, John Grunsfeld, Mike Massimino, Andrew Feustel and Michael Good. McArthur will serve as the flight engineer and lead for robotic arm operations while the remaining mission specialists pair up for the hands-on spacewalk work after Hubble is captured and secured in the payload bay. Altman, Grunsfeld and Massimino are space shuttle and Hubble mission veterans. Johnson, Feustel and Good are first-time space fliers. Sign up for EXPRESS SCIENCE NEWS delivery The STS-125 mission is the 126th shuttle flight, the 30th for Atlantis and the second of five planned in 2009. Hubble was delivered to space on April 24, 1990, on an earlier mission: STS-31. STS-125 is referred to as Servicing Mission 4, although it is technically the fifth servicing flight to the telescope. "Hubble has a long history of providing outstanding science and beautiful pictures," said Ed Weiler, associate administrator for NASA's Science Mission Directorate. "If the servicing mission is successful, it will give us a telescope that will continue to astound both scientists and the public for many years to come." Among Hubble's greatest discoveries is the age of the universe (13.7 billion years); the finding that virtually all major galaxies have black holes at their center; the discovery that the process of planetary formation is relatively common; the first ever organic molecule in the atmosphere of a planet orbiting another star; and evidence that the expansion of the universe is accelerating -- caused by an unknown force that makes up approximately 72 percent of the matter-energy content of the universe. Source:NASA

Wake up and smell the coffee -- on the Moon!

	05.15.2009
May 15, 2009: Have you ever wondered how you'd make your morning cup of java if you lived on another planet, or perhaps the moon? That steaming beverage would be a must on a cold lunar morning. But with rare sunlight, no coal or wood to burn, and no flowing water for hydro-electrical power, how would you make that cup of coffee, much less cook breakfast, heat your abode, and power the life support equipment and tools you needed to live and work up there? NASA, planning for a future lunar outpost, has been asking those same questions lately. There's more than one way to generate power on the moon. Fission Surface Power is one of the options NASA is considering. If this method is chosen, an engine invented in the early 1800s by Scottish brothers Robert and James Stirling could help make it work. Right: An artist's concept of a Fission Surface Power system in operation on the lunar surface. [Editor's note: If you have questions about this technology, please contact Marshall Space Flight Center Public Affairs at 256 544 0034.] The Stirlings were so proud of their creation that they made it their namesake – and with good reason. Over the years the Stirling engine -- the reliable, efficient "little engine that could" -- has earned a sterling reputation here on Earth, and it may one day prove its worth on the moon. "Inhabitants of a lunar outpost will need a safe and effective way to generate light and heat and electricity," says Mike Houts of NASA's Marshall Space Flight Center. "The tried and true Stirling engine fits the bill. It's not only reliable and efficient, but also versatile and clean." NASA is partnering with the Department of Energy to develop Fission Surface Power technology to produce heat and feed it into a Stirling engine, which, in turn, would convert heat energy into electricity for use by moon explorers. It's not certain that this kind of power system will be adopted by NASA, but it does have some very appealing qualities. Houts explains: "A key advantage to this power system is that it wouldn't need sunlight to operate. An FSP system could be used to provide power any time, any place, on the surface of moon or Mars. It could be used at the poles and away from the poles, it could weather a cold lunar night, and it would do well in places like deep craters that are always shaded. Not even a swirling, sunlight obscuring, Martian dust storm could stop it." Above: A Fission Surface Power system reference concept. Click on the image for more details. Credit: Mike Houts/NASA. NASA's engine would only need to produce 40 kW or less power – just enough for a lunar outpost. "This power level is high by space standards but extremely low by Earthly standards," says Houts. "It's about 1/20,000th of what a typical Earthly reactor puts out. We'd only need a tiny reactor on the moon – the fueled portion would be only about 10 inches wide by 1½ feet long." It would provide more power with less mass than other power systems. The whole assembly, radiator on top of Stirling engine on top of reactor, could be stowed in a fraction of the lunar lander. Before developing the final system, Houts and his team are testing with non-nuclear power for proof of concept. "We're conducting tests in a thermal vacuum to learn about operating and controlling the system on the moon," says Houts. "We're using resistance heaters to simulate nuclear heat. Electrical resistance produces heat." After the test system proves the viability of the concept, the team could be directed to build the "real thing," drawing heavily on US and international terrestrial reactor experience. Above: An artist's concept of a Fission Surface Power System embedded in lunar regolith. "It would be built from stainless steel and fueled by uranium dioxide. This combination has been used in terrestrial reactors throughout the world, so scientists and engineers are well-versed in its operation." The unit would not be active at launch, but would be "turned on" once in place on the lunar surface, where it would be surrounded by shielding to prevent any hazard from the radiation emitted. "It would be very safe," says Houts. "And the beauty of the system is that it would be practically self-regulating." Here's how it would work: Inside the reactor is a bundle of small tubes filled with uranium. Outside the reactor are control drums -- one side of each drum reflects neutrons and the other side absorbs them, providing a way to control the rate that neutrons escaping the reactor core are reflected back in. To start up the unit, the absorbent side of each control drum is turned out, away from the reactor core, so the reflective material faces in and sends escaping neutrons back in to the core. The resulting increase in available neutrons enables a self-sustaining chain reaction, which produces heat. A coolant (sodium potassium mixture)* flows through the passage-ways between the tubes, picks up the thermal heat produced by the reacting uranium, and transfers the heat to the Stirling engine. The Stirling engine then does its magic** to generate electricity. Meanwhile the coolant, which has "downloaded" some of its cargo (heat) to the Stirling engine, circulates back through the reactor core, where it picks up heat and is ready to repeat the entire cycle. The system would use only a miniscule amount of fuel -- 1 kg of uranium every 15 years – and still have enough reactivity to run for decades. "We give it a life expectancy of 8 years, though, because something else would falter before the fuel would run out." After shutdown, radiation emitted by the system would decrease rapidly. A replacement system could easily be installed at the same site. After all, coffee may be in high demand up there! Source: NASA

FEATURE Winter Wonder Rocket Movie

Jan. 15, 2009: How can a rocket engine that generates scalding 5,000 degree steam and a whopping 13,000 lbs of thrust form delicate icicles at the rim of its nozzle?

It's cryogenic. NASA is using the Common Extensible Cryogenic Engine ("CECE" for short) to develop technologies for a next-generation lunar lander. CECE is fueled by a mixture of -297 F liquid oxygen and -423 F liquid hydrogen. The engine components are super-cooled to similar low temperatures--and that's where the icicles come from. As CECE burns its frigid fuels, hot steam and other gases are propelled out the nozzle. The steam is cooled by the cold nozzle, condensing and eventually freezing to form icicles around the rim.

Click on the image to launch a movie of CECE's surprising fire and ice:

Launch the movie!

Above: The Common Extensible Cryogenic Engine in action during a recent test. Image credit: Pratt & Whitney Rocketdyne. [Larger image] [movie]

Using liquid hydrogen and oxygen in rockets will provide major advantages for landing astronauts on the moon. Hydrogen is very light but enables about 40 percent greater performance (force on the rocket per pound of propellant) than other rocket fuels. Therefore, NASA can use this weight savings to bring a bigger spacecraft with a greater payload to the moon than with the same amount of conventional propellants. CECE is a step forward in NASA's efforts to develop reliable, robust technologies to return to the moon – and a winter wonder.

CECE has just completed a third round of intensive testing by Pratt & Whitney Rocketdyne in West Palm Beach, Florida. Get the full story from nasa.gov.

Source:NASA

The Red Planet is Not a Dead Planet

	1.15.2009
Jan. 15, 2009: Mars today is a world of cold and lonely deserts, apparently without life of any kind, at least on the surface. Indeed it looks like Mars has been cold and dry for billions of years, with an atmosphere so thin, any liquid water on the surface quickly boils away while the sun's ultraviolet radiation scorches the ground. The situation sounds bleak, but research published today in Science Express reveals new hope for the Red Planet. The first definitive detection of methane in the atmosphere of Mars indicates that Mars is still alive, in either a biologic or geologic sense, according to a team of NASA and university scientists. "Methane is quickly destroyed in the Martian atmosphere in a variety of ways, so our discovery of substantial plumes of methane in the northern hemisphere of Mars in 2003 indicates some ongoing process is releasing the gas," says lead author Michael Mumma of NASA's Goddard Space Flight Center. "At northern mid-summer, methane is released at a rate comparable to that of the massive hydrocarbon seep at Coal Oil Point in Santa Barbara, Calif." Right: An artist's concept of a possible geological source of Martian methane: subsurface water, carbon dioxide and the planet's internal heat combine to release the gas. [animation] Methane -- four atoms of hydrogen bound to a carbon atom -- is the main component of natural gas on Earth. It is of interest to astrobiologists because much of Earth's methane come from living organisms digesting their nutrients. However, life is not required to produce the gas. Other purely geological processes, like oxidation of iron, also release methane. "Right now, we don't have enough information to tell if biology or geology -- or both -- is producing the methane on Mars," said Mumma. "But it does tell us that the planet is still alive, at least in a geologic sense. It's as if Mars is challenging us, saying, hey, find out what this means." Sign up for EXPRESS SCIENCE NEWS delivery If microscopic Martian life is producing the methane, it likely resides far below the surface, where it's still warm enough for liquid water to exist. Liquid water, as well as energy sources and a supply of carbon, are necessary for all known forms of life. "On Earth, microorganisms thrive 2 to 3 kilometers (about 1.2 to 1.9 miles) beneath the Witwatersrand basin of South Africa, where natural radioactivity splits water molecules into molecular hydrogen (H2) and oxygen (O). The organisms use the hydrogen for energy. It might be possible for similar organisms to survive for billions of years below the permafrost layer on Mars, where water is liquid, radiation supplies energy, and carbon dioxide provides carbon," says Mumma. "Gases, like methane, accumulated in such underground zones might be released into the atmosphere if pores or fissures open during the warm seasons, connecting the deep zones to the atmosphere at crater walls or canyons," he says. "Microbes that produced methane from hydrogen and carbon dioxide were one of the earliest forms of life on Earth," notes Carl Pilcher, Director of the NASA Astrobiology Institute which partially supported the research. "If life ever existed on Mars, it's reasonable to think that its metabolism might have involved making methane from Martian atmospheric carbon dioxide." Above: This graphic shows one way methane is destroyed in the Martian atmosphere: the molecules are rapidly broken apart by solar ultraviolet radiation. Because methane doesn't last long in the martian environment, any methane found there must be recently produced. [animation] However, it is possible a geologic process produced the Martian methane, either now or eons ago. On Earth, the conversion of iron oxide (rust) into the serpentine group of minerals creates methane, and on Mars this process could proceed using water, carbon dioxide, and the planet's internal heat. Another possibility is vulcanism: Although there is no evidence of currently active Martian volcanoes, ancient methane trapped in ice "cages" called clathrates might now be released. The team found methane in the atmosphere of Mars by carefully observing the planet over several Mars years (and all Martian seasons) using spectrometers attached to telescopes at NASA's Infrared Telescope Facility, run by the University of Hawaii, and the W. M. Keck telescope, both at Mauna Kea, Hawaii. "We observed and mapped multiple plumes of methane on Mars, one of which released about 19,000 metric tons of methane," says Geronimo Villanueva of the Catholic University of America in Washington, D.C. Villanueva is stationed at NASA Goddard and is co-author of the paper. "The plumes were emitted during the warmer seasons -- spring and summer -- perhaps because the permafrost blocking cracks and fissures vaporized, allowing methane to seep into the Martian air. Curiously, some plumes had water vapor while others did not," he says. Above: Methane plumes found in Mars' atmosphere during the northern summer season. Credit: Trent Schindler/NASA [animation] According to the team, the plumes were seen over areas that show evidence of ancient ground ice or flowing water. For example, plumes appeared over northern hemisphere regions such as east of Arabia Terra, the Nili Fossae region, and the south-east quadrant of Syrtis Major, an ancient volcano 1,200 kilometers (about 745 miles) across. It will take future missions, like NASA's Mars Science Laboratory, to discover the origin of the Martian methane. One way to tell if life is the source of the gas is by measuring isotope ratios. Isotopes are heavier versions of an element; for example, deuterium is a heavier version of hydrogen. In molecules that contain hydrogen, like water and methane, the rare deuterium occasionally replaces a hydrogen atom. Since life prefers to use the lighter isotopes, if the methane has less deuterium than the water released with it on Mars, it's a sign that life is producing the methane. Whatever future research reveals--biology or geology--one thing is already clear: Mars is not so dead, after all. Source: NASA

Giant Rockets Could Revolutionize Astronomy

	01.14.2009
Jan. 14, 2009: In the game of astronomy, size matters. To get crisp, clear images of things billions of light years away, a telescope needs to be big. "The bigger the better," says astronomer Harley Thronson, who leads advanced concept studies in astronomy at the Goddard Space Flight Center. And he thinks "NASA's new Ares V rocket is going to completely change the rules of the game." Ares V is the rocket that will deliver NASA's next manned lunar lander to the moon as well as all the cargo needed for a lunar base. Its roomy shroud could hold about eight school buses, and the rocket will pack enough power to boost almost 180,000 kg (396,000 lbs -- about 16 or 17 school buses) into low Earth orbit. Ares V can haul six times more mass and three times the volume the space shuttle can. "Imagine the kind of telescope a rocket like that could launch," says Thronson. "It could revolutionize astronomy." Right: The roomy shroud of the Ares V could hold about eight school buses. Credit: NASA Optical engineer Phil Stahl of the Marshall Space Flight Center offers this example: "Ares V could carry an 8-meter diameter monolithic telescope, something that we already have the technology to build. The risk would be relatively low, and there are some big cost advantages in not having to cram a large telescope into a smaller launcher." For comparison, he points out that Hubble is only 2.4 meters wide. An 8-meter monolithic telescope would see things more than three times as sharply as Hubble can. More importantly, in the same amount of observing time, the larger mirror would see objects that are about 11 times fainter than Hubble sees because the 8-meter telescope has 11 times the light collecting area. But Ares V can go yet bigger. It could transport a huge segmented telescope – one with several separate mirror panels that are folded up for transport like the James Webb Space Telescope--but three times the size! Sign up for EXPRESS SCIENCE NEWS delivery The Space Telescope Science Institute's Marc Postman has been planning a 16-meter segmented optical/ultraviolet telescope called ATLAST, short for Advanced Technology Large-Aperture Space Telescope. The science from an aperture its size would be spectacular. "ATLAST would be nearly 2000 times more sensitive than the Hubble Telescope and would provide images about seven times sharper than either Hubble or James Webb," says Postman. "It could help us find the long sought answer to a very compelling question -- 'Is there life elsewhere in the galaxy?'" ATLAST's superior sensitivity would allow astronomers to hugely increase their sample size of stars for observation. Then, discovery of planets hospitable to life could be just around the corner! "With our space-based telescope, we could obtain the spectrum of Earth-mass planets orbiting a huge number of nearby [60 - 70 light years from Earth] stars," says Postman. "We could detect any oxygen and water in the planets' spectral signatures. ATLAST could also precisely determine the birth dates of stars in nearby galaxies, giving us an accurate description of how galaxies assemble their stars." Above: Even the smallest space telescope envisioned for launch onboard the Ares V would dwarf Hubble. Image credit: NASA. This telescope could also probe the link between galaxies and black holes. Scientists know that almost all modern galaxies have supermassive black holes in their centers. "There must be a fundamental relationship between the formation of supermassive black holes and the formation of galaxies," explains Postman, "but we don't understand the nature of that relationship. Do black holes form first and act as seeds for the growth of galaxies around them? Or do galaxies form first and serve as incubators for supermassive black holes? A large UV/optical telescope could answer this question: If our telescope finds ancient galaxies that do not have supermassive black holes in their centers, it will mean galaxies can exist without them." Dan Lester of the University of Texas at Austin envisions another 16-meter telescope, this one for detecting far-infrared wavelengths. "The far-infrared telescope is quite different from, and quite complementary to, the optical telescopes of Stahl and Postman," says Lester. "In the far-infrared part of the spectrum, we generally aren't looking at starlight itself, but at the glow of warm dust and gas that surrounds the stars. In the very early stages of star formation, the proto-star is surrounded by layers of dust that visible light can't penetrate. Our telescope will allow us to see down into the innards of these giant dense clouds that are forming stars deep inside." Observations in the far-infrared are especially challenging. These long wavelengths are hundreds of times larger than visible light, so it's hard to get a clear picture. "A very big telescope is necessary for good clarity at IR wavelengths," notes Lester. Above: An artist's concept of the Single Aperture Far-Infrared Telescope (SAFIR) that could be launched aboard the Ares V. [Larger image] Like the telescopes of Stahl and Postman, Lester's Single Aperture Far-Infrared Telescope ('SAFIR' for short), comes in two flavors for the Ares V: an 8-meter monolithic version and a 16-meter segmented version. Lester realized that, with an Ares V, he could launch an 8-meter telescope that didn't need complicated folding and unfolding. "But on the other hand, if we don't mind adding the complexity and cost of folding and still use an Ares V, we could launch a really mammoth telescope," says Lester. In addition to all the above telescopes, Ares V could boost an 8-meter-class X-ray telescope into space. NASA's highly-successful Chandra X-ray Observatory has a 1 meter diameter mirror, so just imagine what an 8-meter Chandra might reveal! Roger Brissenden of the Chandra X-ray Center is excited about the possibility of a future 8-meter-class X-ray telescope called Gen-X. "Gen-X would be an extraordinarily powerful X-ray observatory that could open up new frontiers in astrophysics," he says. "This telescope will observe the very first black holes, stars and galaxies, born just a few hundred million years after the Big Bang, and help us determine how these evolve with time. Right now, the study of the young universe is almost purely in the realm of theory, but with Gen-X's extreme sensitivity (more than 1000 times that of Chandra) these early objects would be revealed." Indeed, Ares V flings shutters open wide on our view of the cosmos. It shakes off the shackles of mass and volume constraints from science missions and sweeps us into deep space to view "...a hundred things/ You have not dreamed of." "We could get incredible astronomy from this big rocket," says Thronson, a professional dreamer. "I can't wait." Source:NASA

Biggest Full Moon of the Year: Take 2

January 8, 2009: When last month's full Moon rose over Florida, onlooker Raquel Stanton of Cocoa Beach realized that something was up. "The Moon was stunningly gorgeous--and it looked bigger than usual!" she says. "My whole family noticed and watched in awe." Like millions of others around the world, she had witnessed the biggest full Moon of 2008--a "perigee Moon," 14% wider and 30% brighter than lesser Moons she had seen before. "I'll never forget it." Alert: It's about to happen again. This Saturday night, Jan. 10th, another perigee Moon is coming. It's the biggest full Moon of 2009, almost identical to the one that impressed onlookers in Dec. 2008. Above: The perigee full Moon of Dec. 2008. "The moon was very bright and BIG! Just watching it with my telescope was exciting enough, but I had to take this picture for the records," says photographer Ron Hodges of Midland, Texas. Johannes Kepler explained the phenomenon 400 years ago. The Moon's orbit around Earth is not a circle; it is an ellipse, with one side 50,000 km closer to Earth than the other. Astronomers call the point of closest approach "perigee," and that is where the Moon will be this weekend. Perigee full Moons come along once or twice a year. 2008 ended with one and now 2009 is beginning with another. It's the best kind of déjà vu for people who love the magic of a moonlit landscape. January is a snowy month in the northern hemisphere, and the combination of snow + perigee moonlight is simply amazing. When the Moon soars overhead at midnight, the white terrain springs to life with a reflected glow that banishes night, yet is not the same as day. You can read a newspaper, ride a bike, write a letter, and at the same time count the stars overhead. It is an otherworldly experience that really must be sampled first hand. Above: The perigee full of Dec. 2008. "A cold wind was blowing as the Moon set over a neighbor's farm," says photographer Eric Ingmundson of Sparta, Wisconsin. "Next time (Jan. 10th) I plan to use a tripod." Another magic moment happens when the perigee Moon is near the horizon. That is when illusion mixes with reality to produce a truly stunning view. For reasons not fully understood by astronomers or psychologists, low-hanging Moons look unnaturally large when they beam through trees, buildings and other foreground objects. This weekend, why not let the "Moon illusion" amplify a full Moon that's extra-big to begin with? The swollen orb rising in the east at sunset may seem so nearby, you catch yourself reaching out to touch it. You won't be the only one. Even at perigee, the Moon is 360,000 km away, yet the distant beauty beckons to poets, stargazers and NASA with equal force: "Come back," it seems to say, "I'm really not so far away." source:NASA

Sixteen Tons of Moondust

	1.07.2009
...I picked up my shovel and I walked to the mine I loaded sixteen tons of number nine coal .... You load sixteen tons, what do you get .... 1 Jan. 7, 2009: If you listen closely, you might hear a NASA project manager singing this song. Lately, Marshall Space Flight Center's Carole McLemore has been working at the end of a sledge hammer opposite a big pile of rocks, so she has good reason to sing the song Tennessee Ernie Ford made famous. "I call it 'choppin' rocks,' " says McLemore, who manages Marshall's Regolith Simulant Team." The guys keep correcting me. 'It's 'bustin' rocks, Carole,' they say." Whether choppin' or bustin', what's this petite woman doing with a sledge hammer in her hands? She's making fake moon dust. "We call it "simulated lunar regolith'," says McLemore. "We need just the right kind of rocks to make this stuff, and we're getting them from the Stillwater Mine in Nye, Montana." Above: Carole McLemore of the NASA Marshall Space Flight Center busts rocks at the Stillwater Mine in Nye, Montana. [Larger image] The Marshall team is working with the US Geological Survey (USGS) to develop a realistic moondust substitute, or simulant, in support of NASA's future lunar exploration. Team members pound on boulder sized rocks to break them into manageable chunks, dump these chunks into buckets, and lug the buckets over to pickup trucks containing reinforced containers to hold the rocks. The pickups carry the rocks down the mountain for loading onto 18 wheelers that transport tons of the material to the USGS in Denver. The USGS makes the simulant by crushing and grinding the rocks and blending in small amounts of natural minerals according to a well-researched "recipe" to approximate the make up of genuine moondust and moon dirt. Sign up for EXPRESS SCIENCE NEWS delivery This is a lot of work, but McLemore believes it's worth the effort: "NASA plans to send humans to the moon to live and work, and the place is filled with gritty dust and powder that sticks to space suits, equipment – to anything and everything," she explains. "It's even inhaled into lungs. So we need high fidelity simulant to work with here on Earth to learn how to work in the real thing up there on the moon. There simply aren't enough Apollo samples of real moondust to do all the research that needs to be done." Simulated regolith can be used as a "guinea pig" to help researchers find ways to make useful things from moon dirt. A favorite example is concrete. Adding, for instance, epoxy to lunar regolith makes a very strong concrete that could be used to build habitats or other structures. Properly baked, a mixture of sulphur and moondust also makes good concrete, and other recipes are sure to be found as the research progresses. On the moon and later on Mars, local resources are going to be crucial to astronauts who can't remain wholly dependent on Earth for supplies. Working with simulated moondust may help researchers figure out how to extract valuable elements and minerals from the real thing. Above: The moon is blanketed in dust--an ever present fact of life for future lunar explorers. Photo credit: NASA/Apollo 17. [Larger image] "For example, moondust and many moon rocks are rich in oxygen," says Christian Schrader, a geologist on the Marshall regolith team. "If we can figure out how to extract it, humans could actually use moondust as a source of breathable air in a future lunar habitat. And the oxygen, along with the hydrogen that exists in the dirt, rocks, and possibly in polar ice, could be used to generate electricity using fuel cells, which make drinkable water as a by-product. Hydrogen and oxygen are also rocket propellant." It seems that the Stillwater Mine has "the right stuff" to use as feedstock in creating the simulant so vital to lunar research. Some of the rocks there are 2.7 billion years old. "There's a huge magma chamber that formed under the ground there," says Schrader. "The magma crystallized over time and formed thick layers of what we call 'anorthosite.' The geology at Stillwater is roughly analogous to how the moon's highland crust crystallized and cooled, so it's a great place for us to go rock collecting." That's why these scientists are heading up the side of a rocky mountain with sledge hammers and pick axes to pound away at big boulders that promise to yield, albeit with great resistance, good rocks for making regolith. "Sometimes arctic winds blow down off the mountains and pummel us while we work," says Schrader. "It can be brutal." But it's all in the name of science. So don't just stand there leaning on your shovel! Start choppin'! Source: NASA

The World We Avoided by Protecting the Ozone Layer

By Michael Carlowicz, with contributions from Rebecca Lindsey.
Design by Robert Simmon. May 13, 2009

The year is 2065. Nearly two-thirds of Earth’s ozone is gone—not just over

the poles, but everywhere. The infamous ozone hole over Antarctica, first

discovered in the 1980s, is a year-round fixture, with a twin over the North

Pole. The ultraviolet (UV) radiation falling on mid-latitude cities like Washington,

D.C., is strong enough to cause sunburn in just five minutes. DNA-mutating UV

radiation is up more than 500 percent, with likely harmful effects on plants, animals,

and human skin cancer rates.

These maps show computer model predictions of the state of the ozone layer in
2064 without (above left) and with (above right) the effects of international
agreements to curb ozone-destroying chemicals in the 1980s and 90s.
(NASA images by the GSFC Scientific Visualization Studio.)

Such is the world we would have inherited if 193 nations had not agreed to ban

ozone-depleting chemicals, according to atmospheric chemists from NASA’s

Goddard Space Flight Center, the Johns Hopkins University, and the Netherlands

Environmental Assessment Agency. Led by Goddard scientist Paul Newman,

the team used a state-of-the-art model to learn “what might have been” if

chlorofluorocarbons (CFCs) and similar chemicals had not been banned

through the 1989 Montreal Protocol, the first-ever international agreement

on regulation of chemical pollutants.

NASA’s Paul Newman led the interdisciplinary team that modeled the
“World Avoided.” His team envisioned what the Earth would have looked
like with high concentrations of ozone-destroying chemicals in the atmosphere.
(Photograph courtesy Paul Newman.)

“Ozone science and monitoring have improved over the past two decades,

and we have moved to a phase where we [scientists] need to be accountable,”

said Newman, who is serving as a co-chair for the latest “state of the science”

assessment report required by the terms of the Montreal Protocol. “We are at

the point where we have to ask: Were we right about ozone? Did the regulations

work? What kind of world was avoided by phasing out ozone-depleting substances?”

Ozone Chemistry

Ozone is Earth’s natural sunscreen, absorbing most of the incoming UV radiation

from the sun and protecting life from DNA-damaging radiation. The gas is naturally

produced and destroyed by sunlight-driven chemical reactions in the stratosphere,

between about 10 and 50 kilometers above the Earth’s surface. Ozone is made

when oxygen molecules (O₂) absorb ultraviolet light and split into individual atoms

(O), which join with other O₂ molecules to make O₃—ozone. Ozone is destroyed

when molecules containing nitrogen, hydrogen, chlorine, or bromine catalyze reactions

that pair a single O atom with ozone (O₃) to make 2 molecules of O₂. It is a system

with a natural balance.

But chlorofluorocarbons—invented in the early 1890s, and first used in the 1930s as

refrigerants and propellants for chemical sprays—upset that balance. While CFCs

are not reactive at Earth’s surface, they become quite destructive when they are

exposed to ultraviolet light in the upper stratosphere. There, CFCs and their

bromine-based counterparts break up into elemental chlorine and bromine that

repeatedly catalyze ozone destruction. Worst of all, such ozone-depleting chemical

can reside for several decades in the atmosphere before breaking down.

In the late 1970s, a springtime “hole” (areas with total ozone below 220 Dobson
Units) developed in the ozone layer above Antarctica. British researchers stationed
on the ice of Halley Bay, Antarctica, discovered the hole with ground-based
measurements (red). NASA satellites corroborated the discovery (blue) and
mapped the extent of the hole. (NASA graph by Robert Simmon, based on data
from the British Antarctic Survey and GSFC Atmospheric Composition Team.)

The chemical phenomenon opened up a springtime hole over Antarctica in the

1980s. Each winter, stratospheric temperatures are cold enough to form clouds,

even though the air is very dry. Chemical reactions on the surfaces of the cloud

particles convert chlorine from a relatively unreactive form into highly reactive

form. The September sunrise over Antarctica triggers ozone-destroying reactions

by these reactive kinds of chlorine, and the ozone concentration over the South

Pole drops from about 300 Dobson Units to as low as 100 Dobson Units.

(See “What is a Dobson Unit?”) By late spring, the rising temperature stops

the ozone destruction cycle. The ozone layer rebounds over summer and fall.

The ozone hole phenomenon opened the eyes of the world to the effects of

human activity on the atmosphere.

What Might Have Been

In the new analysis, Newman and colleagues set out to predict ozone losses

as if nothing had been done to stop them. The team started with the Goddard

Earth Observing System Chemistry-Climate Model, an earth system model

of atmospheric circulation that accounts for variations in solar energy, atmospheric

chemical reactions, temperature changes and winds, and interactions between

the stratosphere, where ozone is found, and the troposphere, the layer of

atmosphere closest to Earth. Their “world avoided” simulation took months of

computer time to process.

The researchers let global emissions of CFCs and similar compounds in the model

world increase by 3 percent per year, the rate at which they were growing before

regulation in the late 1980s. Then they let the simulated world turn from 1975 to 2065.

With continued production of CFCs, ozone levels worldwide would have dropped

to dangerously low levels. (NASA images by the GSFC Scientific Visualization Studio.)

By the simulated year 2020, 17 percent of global ozone is destroyed, and an ozone

hole forms each year over the Arctic as well as the Antarctic. By 2040, the ozone

“hole”—concentrations below 220 Dobson Units—is global. The UV index in

mid-latitude cities reaches 15 around noon on a clear summer day (10 is considered

extreme today).

Computer models predict that global average ozone will return to levels above

300 Dobson Units by 2064 (the reference future, blue line). In contrast, sustained

increases in the level of CFCs and other ozone-destroying chemicals would have

reduced global ozone below 100 Dobson Units (world avoided, red line). (Graph

adapted from Newman et al., 2009.)

Global reduction in ozone levels would lead to a huge increase in dangerous

ultraviolet (UV) radiation, with summer noontime UV index values at mid-latitudes

rising to 30—three times the level currently considered extreme. (Graph adapted

from Newman et al., 2009.)

“Our world avoided calculation goes a little beyond what I thought would happen,”
said Richard Stolarski, a member of the NASA team and pioneer of atmospheric
ozone research. (NASA photograph by Robert Simmon.)

Surprising Collapse of Tropical Ozone Layer

In the 2050s, something strange happens: ozone levels in the stratosphere over

the tropics collapse to near zero in a span of six years. According to Goddard

scientist and study co-author Richard Stolarski, who was among the pioneers

of atmospheric ozone chemistry in 1970s, the rapid, near-total ozone destruction

is similar to what happens over Antarctica today.

Seeing a similar process occur over the tropics was surprising, says Stolarski,

“because we hadn’t expected the tropical stratosphere would get cold enough

to form stratospheric clouds.” The dramatic cooling appears to be the result of

two processes. “Ozone absorbs UV energy, which causes the surrounding

atmosphere to warm,” explains Stolarski. “So, by itself, loss of ozone leads

to cooling, which is something we expected to see.”

More surprising, says Stolarski, is that the temperature change intensified the

stratosphere’s large-scale, slow-moving circulation pattern. In that circulation, air

from the lower stratosphere rises into the upper stratosphere at tropical latitudes,

spreads toward the poles, and sinks. As air rises, it cools. As the circulation

strengthened, the amount of cooling increased, allowing stratospheric clouds—

today confined to polar latitudes—to form over the tropics. Runaway ozone

destruction followed.

By the end of the model run in 2065, global ozone drops to less than 110 DU,

a 67 percent drop from the 1970s. Year-round Arctic polar values hover between

50 and 100 (down from 500 in 1960). The intensity of UV radiation at Earth’s

surface doubles; at certain shorter wavelengths, intensity rises by as much as

10,000 times. Skin cancer rates would soar.

“Our world avoided calculation goes a little beyond what I thought would happen,”

said Stolarski. “The quantities may not be absolutely correct, but the basic results

clearly indicate what could have happened to the atmosphere. And models sometimes

show you something you weren’t expecting, like the precipitous drop in the tropics.”

“We simulated a world avoided,” said Newman, “and it’s a world we should be

glad we avoided.”

The Real World

The real world has been somewhat kinder. Production of ozone-depleting substances

was finally halted in 1992, though their abundance is only beginning to decline because

the chemicals can reside in the atmosphere for 50 to 100 years. The peak abundance

of CFCs in the atmosphere occurred around 2000, and has decreased by roughly 4

percent to date.

Ozone-destroying chemicals (“Effective Equivalent Stratospheric Chlorine”) would have
increased steadily (red line) if the Montreal Protocol and later agreements limiting CFCs
and other chemicals had not been adopted (gray lines). Observations (black line) agree
with the modeled results based on the latest restrictions. Ozone-destroying chemicals
should approach pre-industrial levels around 2064. (Graph adapted from Newman et
al., 2009.)

Stratospheric ozone has been depleted by 5 to 6 percent at middle latitudes, but has

somewhat rebounded in recent years. The largest recorded Antarctic ozone hole was

recorded in 2006, with holes of slightly smaller size since then. Newman, Stolarski, and

other colleagues have used their model to simulate how the real world ozone layer will

recover as well. Because of climate change from greenhouse gases, they say, the ozone

layer will probably not look exactly like it did in the 1970s.

The Antarctic ozone hole (blue areas), which first appeared in the early 1980s and
peaked in the 2000s, is expected to shrink markedly by 2064. International agreements
successfully mitigated the threat posed by CFCs and other ozone-destroying chemicals.
(NASA images by the GSFC Scientific Visualization Studio.)

“I didn’t think that the Montreal Protocol would work as well as it has, but I was pretty

naive about the politics,” Stolarski added. “The Montreal Protocol is a remarkable

international agreement that should be studied by those involved with global warming

and the attempts to reach international agreement on that topic.”

1. Reference

2. Newman, P. A., Oman, L. D., Douglass, A. R., Fleming, E. L., Frith, S. M.,
3. Hurwitz, M. M., Kawa, S. R., Jackman, C. H., Krotkov, N. A., Nash, E. R.,
4. Nielsen, J. E., Pawson, S., Stolarski, R. S., and Velders, G. J. M. (2009).
5. What would have happened to the ozone layer if chlorofluorocarbons (CFCs)
   
6. had not been regulated? Atmospheric Chemistry and Physics, 9(6), 2113-2128.

Source:NASA