Since scientists know how these kinds of waves -- initiated by a Kelvin-Helmholtz instability if you're being technical -- disperse energy in the water, they can use this information to better understand the corona. This in turn, may help solve an enduring mystery of why the corona is thousands of times hotter than originally expected.

"One of the biggest questions about the solar corona is the heating mechanism," says solar physicist Leon Ofman of NASA’s Goddard Space Flight Center, Greenbelt, Md. and Catholic University, Washington. "The corona is a thousand times hotter than the sun's visible surface, but what heats it up is not well-understood. People have suggested that waves like this might cause turbulence which cause heating, but now we have direct evidence of Kelvin-Helmholtz waves."

Ofman and his Goddard colleague, Barbara Thompson, spotted these waves in images taken on April 8, 2010. These were some of the first images caught on camera by the Solar Dynamics Observatory (SDO), a solar telescope with outstanding resolution that launched on February 11, 2010 and began capturing data on March 24 of that year. The team's results appeared online in Astrophysical Journal Letters on May 19, 2011 and will be published in the journal on June 10.

That these "surfer" waves exist in the sun at all is not necessarily a surprise, since they do appear in so many places in nature including, for example, clouds on Earth and between the bands of Saturn. But observing the sun from almost 93 million miles away means it's not easy to physically see details like this. That's why the resolution available with SDO gets researchers excited.

"The waves we're seeing in these images are so small," says Thompson who in addition to being a co-author on this paper is the deputy project scientist for SDO. "They're only the size of the United States," she laughs.

Kelvin-Helmholtz instabilities occur when two fluids of different densities or different speeds flow by each other. In the case of ocean waves, that's the dense water and the lighter air. As they flow past each other, slight ripples can be quickly amplified into the giant waves loved by surfers. In the case of the solar atmosphere, which is made of a very hot and electrically charged gas called plasma, the two flows come from an expanse of plasma erupting off the sun's surface as it passes by plasma that is not erupting. The difference in flow speeds and densities across this boundary sparks the instability that builds into the waves.

In order to confirm this description, the team developed a computer model to see what takes place in the region. Their model showed that these conditions could indeed lead to giant surfing waves rolling through the corona.

Ofman says that despite the fact that Kelvin-Helmholtz instabilities have been spotted in other places, there was no guarantee they'd be spotted in the sun's corona, which is permeated with magnetic fields. "I wasn't sure that this instability could evolve on the sun, since magnetic fields can have a stabilizing effect," he says. "Now we know that this instability can appear even though the solar plasma is magnetized."

Seeing the big waves suggests they can cascade down to smaller forms of turbulence too. Scientists believe that the friction created by turbulence – the simple rolling of material over and around itself – could help add heating energy to the corona. The analogy is the way froth at the top of a surfing wave provides friction that will heat up the wave. (Surfers of course don't ever notice this, as any extra heat quickly dissipates into the rest of the water.)

Hammering out the exact mechanism for heating the corona will continue to intrigue researchers for some time but, says Thompson, SDO's ability to capture images of the entire sun every 12 seconds with such precise detail will be a great boon. "SDO is not the first solar observatory with high enough visual resolution to be able to see something like this," she says. "But for some reason Kelvin-Helmholtz features are rare. The fact that we spotted something so interesting in some of the first images really shows the strength of SDO."

For more information visit http://www.nasa.gov/mission_pages/sunearth/news/sun-surfing.html

That's why scientists working on, Aquarius, the newest NASA Earth System Science Pathfinder mission aboard the Argentine-built Satelite de Aplicaciones Cientificas (SAC)-D observatory, have devised a plan. They will deploy instruments on floats, research ships, commercial cargo ships, free-drifting platforms, buoys, underwater gliders, and an autonomous underwater vehicle to build a 3-D view of what's happening beneath the ocean surface that affects salinity distribution.

Along with temperature, ocean salinity is a key driver of ocean currents, a critical factor in climate processes, and an indicator of Earth's changing water cycle. Measuring salinity from space has been one of the great technological challenges of satellite ocean studies. But once Aquarius starts delivering its salinity data, with accuracy equal to a pinch of salt in a gallon of water, a new challenge begins.

"The next question is: How do you understand what the satellite sees?" said Yi Chao of NASA's Jet Propulsion Laboratory in Pasadena, Calif. Cho is the Aquarius project scientist. "Without deploying instruments under the ocean's surface, we do not know how to fully interpret the satellite observations of surface salinity."

To help address that question, NASA has a new field experiment: SPURS – Salinity Processes in the Upper Ocean Regional Study. The experiment, which will sample salinity and other key factors, such as ocean temperature and velocity, will take place from spring 2012 to summer 2013 and will include five month-long research ship cruises to the center of the saltiest region in the Atlantic Ocean. In oceanography lingo, it's known as the "Atlantic surface salinity maximum," and it's located about halfway between the southeast U.S. coast and the western coast of North Africa, at about 25 degrees north and 38 degrees west. Many of the methods used for years to take in-ocean measurements of salinity will be put to use, but in a far more concentrated and intensive manner, and, for the first time, they'll be used in combination with Aquarius' satellite salinity readings.

SPURS scientists hope to replicate the study in a contrasting, relatively low-salinity region elsewhere in the ocean in the future.

The scope of the measurements taken during SPURS will give scientists deeper insights into the salinity observations from Aquarius and the physical processes -- temperature changes, currents, turbulence, evaporation, precipitation -- that affect salinity. These are all aspects of the global water cycle, the continuous movement of water through the Earth system by evaporation, condensation, precipitation and runoff. Water cycles from the ocean to the atmosphere and then back to the ocean, either directly or via melting ice caps, rivers or underground aquifers. Scientists see evidence of an accelerating water cycle, driven by climate change. Salinity measurements can indicate how the patterns of freshwater mixing with saltwater are changing due to changes in precipitation, evaporation, and freshwater runoff from rivers and melting ice.

"One of the big questions is how much will the water cycle accelerate because of warming?" said Raymond Schmitt, project scientist for SPURS and an oceanographer at Woods Hole Oceanographic Institution in Woods Hole, Mass. In short, as Earth's lowermost atmospheric layer, the troposphere, warms, its ability to hold water in the form of water vapor increases. This, in turn, increases evaporation over land and the ocean, and quickens the cycle as a whole. As precipitation and evaporation patterns change -- thus changing how freshwater mixes with salty water -- so do salinities.

"We're seeing big changes in ocean salinities that can only be explained by an increase in the water cycle," Schmitt said. "We see this changing salinity, and we want to relate it to the changing water cycle -- but we have to understand what the ocean is doing."

Designing a Multi-platform Experiment at Sea

The ocean makes up 71 percent of Earth's surface area and represents 97 percent of the world's volume of water. Measuring what's happening with salinity everywhere in the ocean at every depth is an impossible task. So the SPURS scientists decided to focus on one representative region and measure that as a proxy. A network of different instruments creates a "bounded" volume of water to study in the SPURS experiment.

SPURS precisely identifies a specific 3-D portion of the Atlantic Ocean, and sets out to measure key ocean processes there as thoroughly as possible. Starting at the surface, commercial cargo ships carrying basic salinity gauges and deploying disposable thermometers will criss-cross the target region on their regular trade routes. Ocean scientists have partnered with commercial ships to do this for years. SPURS will also take advantage of the existing Argo network of profiling floats that measure temperature and salinity at the surface and below. The floats dive as deep as 1.2 miles (2 kilometers), while returning to the surface every 10 days to transmit their measurements via satellite. The international scientific collaboration began in the late 1990s and now maintains more than 3,000 floats worldwide.

It is the multiple additions beyond these existing measurements that will make SPURS more complex than a typical study of ocean processes. Multiple buoys will take basic meteorological measurements at the surface. But cables running to anchors on the ocean bottom will stretch down as deep as 2.5 miles (4 kilometers) below the surface, while instruments deployed on the cables at different depths will take salinity, temperature and velocity readings. SPURS will also draw on data from NOAA's existing PIRATA (Prediction and Research Array Moored in the Atlantic) network, which uses similar buoys moored to the ocean floor.

In addition, about 75 free-floating surface drifters, outfitted with GPS, temperature and salinity instruments, will be deployed in a radius of several hundred kilometers. Beneath the surface, NASA will deploy teams of two kinds of "gliders" -- torpedo-like autonomous devices that use slight changes in buoyancy and wings to dive up and down and propel themselves forward, collecting data with instruments onboard.

One class of smaller gliders, called "Slocum gliders," which operate in shallower water, will be deployed for 20 to 30 days during each research cruise. Multiple "Seagliders" will also be deployed for six to nine months at a time. These gliders travel in a wider circumference and dive to greater depths.

Finally, from on board during each of the five one-month ship cruises to the site, scientists will operate a CTD profiler (CTD stands for Conductivity, Temperature and Depth) and a battery-powered, propeller-driven autonomous underwater vehicle that they'll be able to control remotely.

"Salinity has never been measured to the level of detail that SPURS is planning," Chao said.

The questions Chao, Schmitt and others hope to begin to answer with SPURS range from the smallest to the largest scale. For one, what are the physical processes that determine the location and magnitude of the high-salinity region in the Atlantic being studied? What is the salinity balance on monthly and seasonal time scales, plus regional and larger spatial scales?

Larger questions include how the ocean will respond to temperature and freshwater changes likely to come with a warming climate. How will the meridional overturning circulation -- the "global ocean conveyor belt," which has such a dominant effect on the planet's climate -- change?

"We can see in the patterns of salinity change that something big is going on with the water cycle," Schmitt said. "Eighty percent of the water cycle happens over the ocean. We need to document and understand how the ocean is responding."

For more information visit http://www.jpl.nasa.gov/news/news.cfm?release=2011-172

"We refer to Jupiter's path as the Grand Tack, because the big theme in this work is Jupiter migrating toward the sun and then stopping, turning around, and migrating back outward," says the paper's first author, Kevin Walsh of the Southwest Research Institute in Boulder, Colo. "This change in direction is like the course that a sailboat takes when it tacks around a buoy."

According to the new model, Jupiter formed in a region of space about three-and-a-half times as far from the sun as Earth is (3.5 astronomical units). Because a huge amount of gas still swirled around the sun back then, the giant planet got caught in the currents of flowing gas and started to get pulled toward the sun. Jupiter spiraled slowly inward until it settled at a distance of about 1.5 astronomical units—about where Mars is now. (Mars was not there yet.)

"We theorize that Jupiter stopped migrating toward the sun because of Saturn," says Avi Mandell, a planetary scientist at NASA Goddard and a co-author on the paper. The other co-authors are Alessandro Morbidelli at the Observatoire de la Cote d'Azur in Nice, France; Sean Raymond at the Observatoire de Bordeaux in France; and David O'Brien at the Planetary Science Institute in Tucson, Ariz.

Like Jupiter, Saturn got drawn toward the sun shortly after it formed, and the model holds that once the two massive planets came close enough to each other, their fates became permanently linked. Gradually, all the gas in between the two planets got expelled, bringing their sun-bound death spiral to a halt and eventually reversing the direction of their motion. The two planets journeyed outward together until Jupiter reached its current position at 5.2 astronomical units and Saturn came to rest at about 7 astronomical units. (Later, other forces pushed Saturn out to 9.5 astronomical units, where it is today.)

The effects of these movements, which took hundreds of thousands to millions of years, were extraordinary.

Jupiter's Do-Si-Do

"Jupiter migrating in and then all the way back out again can solve the long-standing mystery of why the asteroid belt is made up of both dry, rocky objects and icy objects," Mandell says.

Astronomers think that the asteroid belt exists because Jupiter's gravity prevented the rocky material there from coming together to form a planet; instead, the zone remained a loose collection of objects. Some scientists previously considered the possibility that Jupiter could have moved close to the sun at some point, but this presented a major problem: Jupiter was expected to scatter the material in the asteroid belt so much that the belt would no longer exist.

"For a long time, that idea limited what we imagined Jupiter could have done," Walsh notes.

Rather than having Jupiter destroy the asteroid belt as it moved toward the sun, the Grand Tack model has Jupiter perturbing the objects and pushing the whole zone farther out. "Jupiter's migration process was slow," explains Mandell, "so when it neared the asteroid belt, it was not a violent collision but more of a do-si-do, with Jupiter deflecting the objects and essentially switching places with the asteroid belt."

In the same way, as Jupiter moved away from the sun, the planet nudged the asteroid belt back inward and into its familiar location between the modern orbits of Mars and Jupiter. And because Jupiter traveled much farther out than it had been before, it reached the region of space where icy objects are found. The massive planet deflected some of these icy objects toward the sun and into the asteroid belt.

"The end result is that the asteroid belt has rocky objects from the inner solar system and icy objects from the outer solar system," says Walsh. "Our model puts the right material in the right places, for what we see in the asteroid belt today."

Poor Little Mars

The time that Jupiter spent in the inner solar system had another major effect: its presence made Mars smaller than it otherwise would have been. "Why Mars is so small has been the unsolvable problem in the formation of our solar system," says Mandell. "It was the team's initial motivation for developing a new model of the formation of the solar system."

Because Mars formed farther out than Venus and Earth, it had more raw materials to draw on and should be larger than Venus and Earth. Instead, it's smaller. "For planetary scientists, this never made sense," Mandell adds.

But if, as the Grand Tack model suggests, Jupiter spent some time parked in the inner solar system, it would have scattered some material available for making planets. Much of the material past about 1 astronomical unit would have been dispersed, leaving poor Mars out at 1.5 astronomical units with slim pickings. Earth and Venus, however, would have formed in the region richest in planet-making material.

"With the Grand Tack model, we actually set out to explain the formation of a small Mars, and in doing so, we had to account for the asteroid belt," says Walsh. "To our surprise, the model's explanation of the asteroid belt became one of the nicest results and helps us understand that region better than we did before."

Another bonus is that the new model puts Jupiter, Saturn, and the other giant planets in positions that fit very well with the "Nice model," a relatively new theory that explains the movements of these large planets later in the solar system's history.

The Grand Tack also makes our solar system very much like the other planetary systems that have been found so far. In many of those cases, enormous gas-giant planets called "hot Jupiters" sit extremely close to their host stars, much closer than Mercury is to the sun. For planetary scientists, this newfound likeness is comforting.

"Knowing that our own planets moved around a lot in the past makes our solar system much more like our neighbors than we previously thought," says Walsh. "We're not an outlier anymore."

For more information visit http://www.nasa.gov/topics/solarsystem/features/young-jupiter.html

The oracles of modern climate science are the computer models used to forecast climate change. These models, which rely on a myriad of data from many sources, are effective in predicting many climate variables, such as global temperatures. Yet data for some pieces of the climate puzzle have been scarce, including the concentration of dissolved sea salt at the surface of the world's ocean, commonly called ocean surface salinity, subjecting the models to varying margins of error. This salinity is a key indicator of how Earth's freshwater moves between the ocean, land and atmosphere.

Enter Aquarius, a new NASA salinity-measurement instrument slated for launch in June 2011 aboard the Satélite de Aplicaciones Científicas (SAC)-D spacecraft built by Argentina's Comisión Nacional de Actividades Espaciales (CONAE). Aquarius' high-tech, salt-seeking sensors will make comprehensive measurements of ocean surface salinity with the precision needed to help researchers better determine how Earth's ocean interacts with the atmosphere to influence climate. It's a mission that promises to be, to quote the old saying, "worth its salt."

Improving Climate Forecasts

"We ultimately want to predict climate change and have greater confidence in our predictions. Climate models are the only effective means we have to do so," said Aquarius Principal Investigator Gary Lagerloef, a scientist at the Seattle-based independent laboratory Earth & Space Research. "But, a climate model's forecast skill is only as good as its ability to accurately represent modern-day observations."

Density-driven ocean circulation, according to Lagerloef, is controlled as much by salinity as by ocean temperature. Sea salt makes up only 3.5 percent of the world's ocean, but its relatively small presence reaps huge consequences.

Salinity influences the very motion of the ocean and the temperature of seawater, because the concentration of sea salt in the ocean's surface mixed layer -- the portion of the ocean that is actively exchanging water and heat with Earth's atmosphere -- is a critical driver of these ocean processes. It's the missing variable in understanding the link between the water cycle and ocean circulation. Specifically, it's an essential metric to modeling precipitation and evaporation.

Accurate ocean surface salinity data are a necessary component to understanding what will happen in the future, but can also open a window to Earth's climate past. When researchers want to create a climate record that spans previous decades -- which helps them identify trends -- it's necessary to collect and integrate data from the last two to three decades to develop a consistent analysis.

"Aquarius, and successor missions based on it, will give us, over time, critical data that will be used by models that study how Earth's ocean and atmosphere interact, to see trends in climate," said Lagerloef. "The advances this mission will enable make this an exciting time in climate research."

Taking Past Measurements with a Grain of Salt

Anyone who's splashed at the beach knows that ocean water is salty. Yet measuring this simple compound in seawater has been a scientific challenge for well over a century.

Until now, researchers had taken ocean salinity measurements from aboard ships, buoys and aircraft – but they'd done so using a wide range of methods across assorted sampling areas and over inconsistent times from one season to another. Because of the sparse and intermittent nature of these salinity observations, researchers have not been able to fine-tune models to obtain a true global picture of how ocean surface salinity is influencing the ocean. Aquarius promises to resolve these deficiencies, seeing changes in ocean surface salinity consistently across space and time and mapping the entire ice-free ocean every seven days for at least three years.

The Age of Aquarius
Research modelers like William Large, an oceanographer at the National Center for Atmospheric Research in Boulder, Colo., will use Aquarius' ocean surface salinity data, along with precipitation and temperature observations, to round out the data needed to refine the numerical climate models he and his colleagues have developed.

"This mission is sure to mark a new era for end users like us," explained Large. "Aquarius puts us on the road to implementing a long-term, three-step plan that could improve our climate models. The first step will be to use Aquarius data to identify if there is a problem with our models -- what deficiencies exist, for example, in parts of the world where observations are sparse.

"Second, the data will help us determine the source of these problems," Large added. "Salinity helps us understand density -- and density, after all, makes ocean waters sink and float, and circulate around Earth.

"Third, Aquarius will help us solve the puzzle of what's going on in the ocean itself -- the ocean processes," he added. "We'll pair an ocean observation experiment with the satellite mission to explore the mixing and convection -- how things like salinity are stirred in the ocean -- to better determine what processes might be actually changing climate. Measuring salinity at the ocean surface will deliver a pioneering baseline of observations for changes seen by the next generation of missions in the coming decades."

"We've done all of the advance work leading up to the launch of Aquarius, so the proof will be in the actual data," said Lagerloef. "Our intent is to put the data out immediately as soon as the satellite begins transmitting. Before the end of the first year, we'll be interpreting exactly what the data are telling us and how they will benefit climate modeling."

For more information visit http://www.jpl.nasa.gov/news/news.cfm?release=2011-169

Imaging experts funded by the Space Shuttle Program and located at NASA's Ames Research Center prepared this image using fusion software to combine six simultaneously captured images they took of the STS-134 launch on May 16, 2011. Each image was taken at a different exposure setting, then composited to balance the brightness of the rocket engine output with the regular daylight levels at which the orbiter can be seen. The processing software digitally removes pure black or pure white pixels from one image and replaces them with the most detailed pixel option from the five other images. This technique can help visualize debris falling during a launch or support research involving intense light sources like rocket engines, plasma experiments and hypersonic vehicle engines.

For more information visit http://www.nasa.gov/topics/shuttle_station/features/sts-134_launch_photo-video.html

The new map, created from ground- and space-based data, shows, for the first time, the distribution of carbon stored in forests across more than 75 tropical countries. Most of that carbon is stored in the extensive forests of Latin America.

"This is a benchmark map that can be used as a basis for comparison in the future when the forest cover and its carbon stock change," said Sassan Saatchi of NASA's Jet Propulsion Laboratory in Pasadena, Calif., who led the research. "The map shows not only the amount of carbon stored in the forest, but also the accuracy of the estimate." The study was published May 30 in the Proceedings of the National Academy of Sciences.

Deforestation and forest degradation contribute 15 to 20 percent of global carbon emissions, and most of that contribution comes from tropical regions. Tropical forests store large amounts of carbon in the wood and roots of their trees. When the trees are cut and decompose or are burned, the carbon is released to the atmosphere.

Previous studies had estimated the carbon stored in forests on local and large scales within a single continent, but there existed no systematic way of looking at all tropical forests. To measure the size of the trees, scientists typically use a ground-based technique, which gives a good estimate of how much carbon they contain. But this technique is limited because the structure of the forest is extremely variable, and the number of ground sites is very limited.

To arrive at a carbon map that spans three continents, the team used data from the Geoscience Laser Altimeter System lidar on NASA's ICESat satellite. The researchers looked at information on the height of treetops from more than 3 million measurements. With the help of corresponding ground data, they calculated the amount of above-ground biomass and thus, the amount of carbon it contained.

The team then extrapolated these data over the varying landscape to produce a seamless map, using NASA imagery from the Moderate Resolution Imaging Spectroradiometer (MODIS) instrument on NASA's Terra spacecraft, the QuikScat scatterometer satellite and the Shuttle Radar Topography Mission.

The map reveals that in the early 2000s, forests in the 75 tropical countries studied contained 247 billion tons of carbon. For perspective, about 10 billion tons of carbon is released annually to the atmosphere from combined fossil fuel burning and land use changes.

The researchers found that forests in Latin America hold 49 percent of the carbon in the world's tropical forests. For example, Brazil's carbon stock alone, at 61 billion tons, almost equals all of the carbon stock in sub-Saharan Africa, at 62 billion tons.

"These patterns of carbon storage, which we really didn't know before, depend on climate, soil, topography and the history of human or natural disturbance of the forests," Saatchi said. "Areas often impacted by disturbance, human or natural, have lower carbon storage."

The carbon numbers, along with information about the uncertainty of the measurements, are important for countries planning to participate in the Reducing Emissions from Deforestation and Degradation (REDD+) program. REDD+ is an international effort to create a financial value for the carbon stored in forests. It offers incentives for countries to preserve their forestland in the interest of reducing carbon emissions and investing in low-carbon paths of development.

The map also provides a better indication of the health and longevity of forests and how they contribute to the global carbon cycle and overall functioning of the Earth system. The next step in Saatchi's research is to compare the carbon map with satellite observations of deforestation to identify source locations of carbon dioxide released to the atmosphere.

For more information visit http://www.jpl.nasa.gov/news/news.cfm?release=2011-165

In addition, R1 (Minor) radio blackouts also occurred due to solar flares on the Sun. NOAA is predicting a continuing possibility of category R1 radio blackouts through June 9, 2011.

What is a coronal hole?

The solar corona is the outer atmosphere of the sun, extending from the solar surface out into space. Coronal holes are large regions in the solar corona that appear darker and are less dense and cooler than surrounding areas. The open structure of their magnetic field allows a constant flow of high-density plasma to stream out of the holes. The high-speed solar wind is known to originate in coronal holes.

There is an increase in the intensity of the solar wind effects on Earth when a coronal hole faces us. During solar minimum, coronal holes are mainly found at the Sun's polar regions. They can be located anywhere on the sun during solar maximum, which is our sun's current cycle. Coronal holes are the sources of many of the disturbances to the ionosphere (and HF communications) and to the geomagnetic field of planet Earth.

For more information visit http://www.nasa.gov/mission_pages/sunearth/news/News060111-geostorm.html

Infrared imagery basically shows temperature signatures. That means that scientists can determine how hot or cold something is by looking at something using infrared light. The Atmospheric Infrared Sounder (AIRS) instrument aboard NASA's Aqua satellite captured infrared imagery when it flew over severe thunderstorms in northwestern Georgia on May 27 at 07:17 UTC (3:17 a.m. EDT).

The infrared image from AIRS revealed a circular shaped area of thunderstorms over northwestern Georgia, with very high thunderstorm cloud-tops. AIRS data measured the cloud top temperatures to be as cold as or colder than -63 Fahrenheit/-52 Celsius. The rule with thunderstorms is that the higher the cloud top, the colder it is and the stronger the thunderstorm. These storms have the potential of dropping as much as 2 inches (50 mm) of rainfall per hour.

The image also showed a somewhat scraggly line of high thunderstorm cloud tops, indicative of the cold front those storms are a part of that stretch from northwestern Georgia up the western side of the Appalachian mountains to northwestern Maine. That line is moving east with the progression of the cold front on May 28.

The National Weather Service's Hydrometeorological Prediction Center in Camp Springs, Md. noted on May 28 "a weakening upper-level closed low over the Ohio valley will lift northeastward into southern Canada by Saturday. Showers and thunderstorms will develop along and ahead of the associated weakening cold front from the eastern gulf coast to the central Appalachians moving eastward to the mid-Atlantic and southward to the southeast."

The area on the AIRS imagery where the very high, cold, strong thunderstorms were located may have experienced a tornado. Chattoga County in northwestern Georgia reported damage from storms that may have been caused by a tornado. Chattooga County is about 80 miles northwest of the city of Atlanta. Today, the National Weather Service is investigating reported damages to determine if a tornado touched down. A small private airport in the county suffered damage to hangars and flipped planes, according to Channel 2, WSB-TV, Atlanta. The damage path began on Lookout Mountain and spread into the valley below, damaging homes, downing trees and power lines. Atlanta was not spared from severe weather from this system either. According to reports from Fox 5 television, Atlanta three people lost their lives from fallen trees. The National Weather Service reported golf-ball to softball-sized hail in Gwinnett and Fannin Counties. Power outages were reported in the Metro Atlanta area and in Dekalb and Clayton counties.

The AIRS instrument is one of several that fly onboard NASA's Aqua Satellite. With its ability to create three-dimensional maps of the atmosphere showing temperature, water vapor, and cloud properties, AIRS provides a unique view of the environment in which storms come to life. For more information about AIRS, visit: http://airs.jpl.nasa.gov/.

For more information visit http://www.nasa.gov/topics/earth/features/georgia-20110527.html

Caption for Phil Campbell, Ala., Image 2: Similar to the radar and satellite composite imagery provided for the Tuscaloosa, Ala. tornado, this image from Phil Campbell, Ala. shows radar reflectivity from the National Weather Service Doppler Radar at Columbus Air Force Base, Miss. at 3:33 p.m. CDT as a strong supercell departed Marion County, Ala. and entered Franklin County, Ala. As in the Tuscaloosa case, the “hook echo” signature is apparent with enhanced radar reflectivity along the damage scar indicated by Advanced Spaceborne Thermal Emission and Reflection Radiometer, or ASTER satellite data, likely corresponding to lofted debris. Damage in the Phil Campbell area was rated as an EF-5 and continued northeast before weakening slightly in the Mount Hope, Ala. area. The damage scar continues southwest into Marion County, Ala., through the community of Hackleburg, Ala. -- not shown -- and further to the northeast as the storm continued into southwestern Lawrence County, Ala.

These images were created by the NASA Short-term Prediction Research and Transition, or SPoRT, Center at Marshall Space Flight Center in Huntsville, Ala., using ASTER data provided courtesy of NASA's Goddard Space Flight Center in Greenbelt, Md.; the United States Geological Survey Land Processes Distributed Active Archive Center in Sioux Falls, S.D., Japan's Earth Remote Sensing Data Analysis Center in Tokyo, Japan; the Ministry of Economy, Trade and Industry, along with the Japan Research Observation System Organization. Final ASTER imagery were produced using resources of the Nebula Cloud Computing Platform, tiled, and displayed within Google Earth. Radar imagery were provided by the NOAA National Climatic Data Center's NEXRAD Archive in Asheville, N.C. Storm survey information was provided by the National Weather Service Forecast Offices in Birmingham and Huntsville, Ala.

For more information visit http://www.nasa.gov/topics/earth/features/alabama_tornadoes.html

This is the first time such crystals have been observed in the dusty clouds of gas that collapse around forming stars. Astronomers are still debating how the crystals got there, but the most likely culprits are jets of gas blasting away from the embryonic star.

"You need temperatures as hot as lava to make these crystals," said Tom Megeath of the University of Toledo in Ohio. He is the principal investigator of the research and the second author of a new study appearing in Astrophysical Journal Letters. "We propose that the crystals were cooked up near the surface of the forming star, then carried up into the surrounding cloud where temperatures are much colder, and ultimately fell down again like glitter."

Spitzer's infrared detectors spotted the crystal rain around a distant, sun-like embryonic star, or protostar, referred to as HOPS-68, in the constellation Orion.

The crystals are in the form of forsterite. They belong to the olivine family of silicate minerals and can be found everywhere from a periodot gemstone to the green sand beaches of Hawaii to remote galaxies. NASA's Stardust and Deep Impact missions both detected the crystals in their close-up studies of comets.

"If you could somehow transport yourself inside this protostar's collapsing gas cloud, it would be very dark," said Charles Poteet, lead author of the new study, also from the University of Toledo. "But the tiny crystals might catch whatever light is present, resulting in a green sparkle against a black, dusty backdrop."

Forsterite crystals were spotted before in the swirling, planet-forming disks that surround young stars. The discovery of the crystals in the outer collapsing cloud of a proto-star is surprising because of the cloud's colder temperatures, about minus 280 degrees Fahrenheit (minus 170 degrees Celsius). This led the team of astronomers to speculate the jets may in fact be transporting the cooked-up crystals to the chilly outer cloud.

The findings might also explain why comets, which form in the frigid outskirts of our solar system, contain the same type of crystals. Comets are born in regions where water is frozen, much colder than the searing temperatures needed to form the crystals, approximately 1,300 degrees Fahrenheit (700 degrees Celsius). The leading theory on how comets acquired the crystals is that materials in our young solar system mingled together in a planet-forming disk. In this scenario, materials that formed near the sun, such as the crystals, eventually migrated out to the outer, cooler regions of the solar system.

Poteet and his colleagues say this scenario could still be true but speculate that jets might have lifted crystals into the collapsing cloud of gas surrounding our early sun before raining onto the outer regions of our forming solar system. Eventually, the crystals would have been frozen into comets. The Herschel Space Observatory, a European Space Agency-led mission with important NASA contributions, also participated in the study by characterizing the forming star.

"Infrared telescopes such as Spitzer and now Herschel are providing an exciting picture of how all the ingredients of the cosmic stew that makes planetary systems are blended together," said Bill Danchi, senior astrophysicist and program scientist at NASA Headquarters in Washington.

The Spitzer observations were made before it used up its liquid coolant in May 2009 and began its warm mission.

NASA's Jet Propulsion Laboratory in Pasadena, Calif., manages the Spitzer Space Telescope mission for the agency's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

For more information visit http://www.nasa.gov/mission_pages/spitzer/news/spitzer20110526.html

The Webb telescope will experience significant shaking and gravitational forces when it is launched on the large Ariane V rocket. The ISIM structure will house the four main scientific instruments of the telescope.

During the testing process, as the ISIM structure is being spun and shaken, engineers take measurements to compare with their computer models. If there are discrepancies, the engineers hunt for the reasons so they can address them. The huge centrifuge will spin at speeds close to 11 rpm, exposing the ISIM structure to about 10 times the force of gravity.

Webb is the successor to the Hubble Space Telescope and will serve thousands of astronomers worldwide. Webb will study the history of our Universe, ranging from the first luminous glows after the Big Bang, to the formation of planetary systems capable of supporting life on planets like Earth, to the evolution of our own Solar System. The Webb telescope is a joint mission of NASA, the European Space Agency and Canadian Space Agency.

For more information visit http://www.nasa.gov/topics/technology/features/isim-spin-test.html

The lower energy X-rays in this image are red, the medium energy X-rays are green, and the highest energy X-rays are blue. The Chandra survey has a large field of 1.4 square degrees, made of a mosaic of 22 individual Chandra pointings. In total, this image represents 1.2 million seconds -- or nearly two weeks -- of Chandra observing time. A great deal of multi-wavelength data has been used in combination with this new Chandra campaign, including infrared observations from the Spitzer Space Telescope and the Very Large Telescope (VLT).

Several pieces of evidence support the idea that supernova production has already begun in this star-forming region. Firstly, there is an observed deficit of bright X-ray sources in Trumpler 15, suggesting that some of the massive stars in this cluster were already destroyed in supernova explosions. Trumpler 15 is located in the northern part of the image, as shown in a labeled version, and is one of ten star clusters in the Carina complex. Several other well known clusters are shown in the labeled image.

The detection of six possible neutron stars, the dense cores often left behind after stars explode in supernovas, provides additional evidence that supernova activity is ramping up in Carina. Previous observations had only detected one neutron star in Carina. These six neutron star candidates are too faint to be easily picked out in this large-scale image of Carina.

For more information visit http://www.nasa.gov/mission_pages/chandra/multimedia/carina2011.html

Blue stragglers are so named because they seemingly lag behind in the aging process, appearing younger than the population from which they formed. While they have been detected in many distant star clusters, and among nearby stars, they never have been seen inside the core of our galaxy.

It is not clear how blue stragglers form. A common theory is that they emerge from binary pairs. As the more massive star evolves and expands, the smaller star gains material from its companion. This stirs up hydrogen fuel and causes the growing star to undergo nuclear fusion at a faster rate. It burns hotter and bluer, like a massive young star.

The findings support the idea that the Milky Way's central bulge stopped making stars billions of years ago. It now is home to aging sun-like stars and cooler red dwarfs. Giant blue stars that once lived there have long since exploded as supernovae.

The results have been accepted for publication in an upcoming issue of The Astrophysical Journal. Lead author Will Clarkson of Indiana University in Bloomington, will discuss them today at the American Astronomical Society meeting in Boston.

"Although the Milky Way bulge is by far the closest galaxy bulge, several key aspects of its formation and subsequent evolution remain poorly understood," Clarkson said. "Many details of its star-formation history remain controversial. The extent of the blue straggler population detected provides two new constraints for models of the star-formation history of the bulge."

The discovery followed a seven-day survey in 2006 called the Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS). Hubble peered at 180,000 stars in the crowded central bulge of our galaxy, 26,000 light-years away. The survey was intended to find hot Jupiter-class planets that orbit very close to their stars. In doing so, the SWEEPS team also uncovered 42 oddball blue stars with brightness and temperatures typical for stars much younger than ordinary bulge stars.

The observations clearly indicate that if there is a young star population in the bulge, it is very small. It was not detected in the SWEEPS program. Blue stragglers long have been suspected to be living in the bulge, but had not been observed because younger stars in the disk of our galaxy lie along the line-of-sight to the core, confusing and contaminating the view.

Astronomers used Hubble to distinguish the motion of the core population from foreground stars in the Milky Way. Bulge stars orbit the galactic center at a different speed than foreground stars. Plotting their motion required returning to the SWEEPS target region with Hubble two years after the first observations were made. The blue stragglers were identified as moving along with the other stars in the bulge.

"The size of the field of view on the sky is roughly that of the thickness of a human fingernail held at arm's length, and within this region, Hubble sees about a quarter million stars toward the bulge," Clarkson said. "Only the superb image quality and stability of Hubble allowed us to make this measurement in such a crowded field."

From the 42 candidate blue stragglers, the investigators estimate 18 to 37 are likely genuine. The remainder could be a mix of foreground objects and, at most, a small population of genuinely young bulge stars.

"The SWEEPS program was designed to detect transiting planets through small light variations" said Kailash Sahu, the principal investigator of the SWEEPS program. "Therefore the program could easily detect the variability of binary pairs, which was crucial in confirming these are indeed blue stragglers."

Hubble is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Md., manages the telescope. The Space Telescope Science Institute (STScI) conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy in Washington.

For more information visit http://www.nasa.gov/mission_pages/hubble/science/blue-straggler.html

"These jets arise as infalling matter approaches the black hole, but we don't yet know the details of how they form and maintain themselves," said Cornelia Mueller, the study's lead author and a doctoral student at the University of Erlangen-Nuremberg in Germany.

The new image shows a region less than 4.2 light-years across -- less than the distance between our sun and the nearest star. Radio-emitting features as small as 15 light-days can be seen, making this the highest-resolution view of galactic jets ever made. The study will appear in the June issue of Astronomy and Astrophysics and is available online.

Mueller and her team targeted Centaurus A (Cen A), a nearby galaxy with a supermassive black hole weighing 55 million times the sun's mass. Also known as NGC 5128, Cen A is located about 12 million light-years away in the constellation Centaurus and is one of the first celestial radio sources identified with a galaxy.

Seen in radio waves, Cen A is one of the biggest and brightest objects in the sky, nearly 20 times the apparent size of a full moon. This is because the visible galaxy lies nestled between a pair of giant radio-emitting lobes, each nearly a million light-years long.

These lobes are filled with matter streaming from particle jets near the galaxy's central black hole. Astronomers estimate that matter near the base of these jets races outward at about one-third the speed of light.

Using an intercontinental array of nine radio telescopes, researchers for the TANAMI (Tracking Active Galactic Nuclei with Austral Milliarcsecond Interferometry) project were able to effectively zoom into the galaxy's innermost realm.

"Advanced computer techniques allow us to combine data from the individual telescopes to yield images with the sharpness of a single giant telescope, one nearly as large as Earth itself," said Roopesh Ojha at NASA's Goddard Space Flight Center in Greenbelt, Md.

The enormous energy output of galaxies like Cen A comes from gas falling toward a black hole weighing millions of times the sun's mass. Through processes not fully understood, some of this infalling matter is ejected in opposing jets at a substantial fraction of the speed of light. Detailed views of the jet's structure will help astronomers determine how they form.

The jets strongly interact with surrounding gas, at times possibly changing a galaxy's rate of star formation. Jets play an important but poorly understood role in the formation and evolution of galaxies.

NASA's Fermi Gamma-ray Space Telescope has detected much higher-energy radiation from Cen A's central region. "This radiation is billions of times more energetic than the radio waves we detect, and exactly where it originates remains a mystery," said Matthias Kadler at the University of Wuerzburg in Germany and a collaborator of Ojha. "With TANAMI, we hope to probe the galaxy's innermost depths to find out."

Ojha is funded through a Fermi investigation on multiwavelength studies of Active Galactic Nuclei.

The astronomers credit continuing improvements in the Australian Long Baseline Array (LBA) with TANAMI's enormously increased image quality and resolution. The project augments the LBA with telescopes in South Africa, Chile and Antarctica to explore the brightest galactic jets in the southern sky.

NASA’s Fermi Gamma-ray Space Telescope is an astrophysics and particle physics partnership, developed in collaboration with the U.S. Department of Energy, along with important contributions from academic institutions and partners in France, Germany, Italy, Japan, Sweden and the U.S. The Australia Long Baseline Array is part of the Australia Telescope National Facility, which is funded by the Commonwealth of Australia for operation as a National Facility managed by the Commonwealth Scientific and Industrial Research Organization.

For more information visit http://www.nasa.gov/topics/universe/features/radio-particle-jets.html

The star goes by the inauspicious name of Hubble variable number one, or V1, and resides in the outer regions of the neighboring Andromeda galaxy, or M31. But in the early 1900s, most astronomers considered the Milky Way a single "island universe" of stars, with nothing observable beyond its boundaries. Andromeda was cataloged as just one of many faint, fuzzy patches of light astronomers called "spiral nebulae."

Were these spiral nebulae part of the Milky Way or were they independent island universes lying outside our galaxy? Astronomers didn't know for sure, until Edwin Hubble found a star in Andromeda that brightened and faded in a predictable pattern, like a lighthouse beacon, and identified it as V1, a Cepheid variable. This special type of star had already been proven to be a reliable distance marker within our galaxy.

The star helped Hubble show that Andromeda was beyond our galaxy and settled the debate over the status of the spiral nebulae. The universe became a much bigger place after Hubble's discovery, much to the dismay of astronomer Harlow Shapley, who believed the fuzzy nebulae were part of our Milky Way.

Nearly 90 years later, V1 is in the spotlight again. Astronomers pointed Edwin Hubble's namesake, NASA's Hubble Space Telescope, at the star once again, in a symbolic tribute to the legendary astronomer's milestone observation.

Astronomers with the Space Telescope Science Institute's Hubble Heritage Project partnered with the American Association of Variable Star Observers (AAVSO) to study the star. AAVSO observers followed V1 for six months, producing a plot, or light curve, of the rhythmic rise and fall of the star's light. Based on this light curve, the Hubble Heritage team scheduled telescope time to capture images of the star.

"V1 is the most important star in the history of cosmology," says astronomer Dave Soderblom of the Space Telescope Science Institute (STScI) in Baltimore, Md., who proposed the V1 observations.

"It's a landmark discovery that proved the universe is bigger and chock full of galaxies. I thought it would be nice for the Hubble telescope to look at this special star discovered by Hubble, the man."

But Hubble Heritage team member Max Mutchler of the STScI says that this observation is more than just a ceremonial nod to a famous astronomer.

"This observation is a reminder that Cepheids are still relevant today," he explains. "Astronomers are using them to measure distances to galaxies much farther away than Andromeda. They are the first rung on the cosmic distance ladder."

The Hubble and AAVSO observations of V1 will be presented at a press conference May 23 at the American Astronomical Society meeting in Boston, Mass.

Ten amateur astronomers from around the world, along with AAVSO Director Arne Henden, made 214 observations of V1 between July 2010 and December 2010. They obtained four pulsation cycles, each of which lasts more than 31 days. The AAVSO study allowed the Hubble Heritage team to target Hubble observations that would capture the star at its brightest and dimmest phases.

The observations were still tricky, though. "The star's brightness has a gradual decline followed by a sharp spike upward, so if you're off by a day or two, you could miss it," Mutchler explains.

Using the Wide Field Camera 3, the team made four observations in December 2010 and January 2011.

"The Hubble telescope sees many more and much fainter stars in the field than Edwin Hubble saw, and many of them are some type of variable star," Mutchler says. "Their blinking makes the galaxy seem alive. The stars look like grains of sand, and many of them have never been seen before."

For Soderblom, the Hubble observations culminated more than 25 years of promoting the star. Shortly after Soderblom arrived at the Institute in 1984, he thought it would be fitting to place a memento of Edwin Hubble's aboard the space shuttle Discovery, which would carry the Hubble Space Telescope into space.

"At first, I thought the obvious artifact would be his pipe, but [cosmologist] Allan Sandage [Edwin Hubble's protege] suggested another idea: the photographic glass plate of V1 that Hubble made in 1923," Soderblom recalls.

He made 15 film copies of the original 4-inch-by-5-inch glass plate. Ten of them flew onboard space shuttle Discovery in 1990 on the Hubble deployment mission. Fittingly, two of the remaining five film copies were part of space shuttle Atlantis's cargo in 2009 for NASA's fifth servicing mission to Hubble. One of those copies was carried aboard by astronaut and astronomer John Grunsfeld, now the STScI's deputy director.

Telltale Star Expands the Known Universe

Prior to the discovery of V1 many astronomers thought spiral nebulae, such as Andromeda, were part of our Milky Way galaxy. Others weren't so sure. In fact, astronomers Shapley and Heber Curtis held a public debate in 1920 over the nature of these nebulae. During the debate, Shapley championed his measurement of 300,000 light-years for the size of the Milky Way. Though Shapley overestimated its size, he was correct in asserting that the Milky Way was much larger than the commonly accepted dimensions. He also argued that spiral nebulae were much smaller than the giant Milky Way and therefore must be part of our galaxy. But Curtis disagreed. He thought the Milky Way was smaller than Shapley claimed, leaving room for other island universes beyond our galaxy.

To settle the debate, astronomers had to establish reliable distances to the spiral nebulae. So they searched for stars in the nebulae whose intrinsic brightness they thought they understood. Knowing a star's true brightness allowed astronomers to calculate how far away it was from Earth. But some of the stars they selected were not dependable milepost markers.

For example, Andromeda, the largest of the spiral nebulae, presented ambiguous clues to its distance. Astronomers had observed different types of exploding stars in the nebula. But they didn't fully understand the underlying stellar processes, so they had difficulty using those stars to calculate how far they were from Earth. Distance estimates to Andromeda, therefore, varied from nearby to far away. Which distance was correct? Edwin Hubble was determined to find out.

The astronomer spent several months in 1923 scanning Andromeda with the 100-inch Hooker telescope, the most powerful telescope of that era, at Mount Wilson Observatory in California. Even with the sharp-eyed telescope, Andromeda was a monstrous target, about 5 feet long at the telescope's focal plane. He therefore took many exposures covering dozens of photographic glass plates to capture the whole nebula.

He concentrated on three regions. One of them was deep inside a spiral arm. On the night of Oct. 5, 1923, Hubble began an observing run that lasted until the early hours of Oct. 6. Under poor viewing conditions, the astronomer made a 45-minute exposure that yielded three suspected novae, a class of exploding star. He wrote the letter "N," for nova, next to each of the three objects.

Later, however, Hubble made a startling discovery when he compared the Oct. 5-6 plate with previous exposures of the novae. One of the so-called novae dimmed and brightened over a much shorter time period than seen in a typical nova.

Hubble obtained enough observations of V1 to plot its light curve, determining a period of 31.4 days, indicating the object was a Cepheid variable. The period yielded the star's intrinsic brightness, which Hubble then used to calculate its distance. The star turned out to be 1 million light-years from Earth, more than three times Shapley's calculated diameter of the Milky Way.

Taking out his marking pen, Hubble crossed out the "N" next to the newfound Cepheid variable and wrote "VAR," for variable, followed by an exclamation point.

For several months the astronomer continued gazing at Andromeda, finding another Cepheid variable and several more novae. Then Hubble sent a letter along with a light curve of V1 to Shapley telling him of his discovery. After reading the letter, Shapley was convinced the evidence was genuine. He reportedly told a colleague, "Here is the letter that destroyed my universe."

By the end of 1924 Hubble had found 36 variable stars in Andromeda, 12 of which were Cepheids. Using all the Cepheids, he obtained a distance of 900,000 light-years. Improved measurements now place Andromeda at 2 million light-years away.

"Hubble eliminated any doubt that Andromeda was extragalactic," says Owen Gingerich, professor emeritus of Astronomy and of the History of Science at Harvard-Smithsonian Center for Astrophysics in Cambridge, Mass. "Basically, astronomers didn't know the distance to novae, so they had to make a rough estimate as to where they were and therefore what their absolute luminosity was. But that is on very treacherous ground. When you get a Cepheid that's been reasonably calculated, the period will tell you where it sits on the luminosity curve, and from that you can calculate a distance."

Shapley and astronomer Henry Norris Russell urged Hubble to write a paper for a joint meeting of the American Astronomical Society and American Association for the Advancement of Science at the end of December 1924. Hubble's paper, entitled "Extragalactic Nature of Spiral Nebulae," was delivered in absentia and shared the prize for the best paper. A short article about the award appeared in the Feb. 10, 1925, issue of The New York Times. Gingerich says Hubble's discovery was not big news at the meeting because the astronomer had informed the leading astronomers of his result months earlier.

Edwin Hubble's observations of V1 became the critical first step in uncovering a larger, grander universe. He went on to find many galaxies beyond the Milky Way. Those galaxies, in turn, allowed him to determine that the universe is expanding.

Could Hubble ever have imagined that nearly 100 years later, technological advances would allow amateur astronomers to perform similar observations of V1 with small telescopes in their backyards? Or, could Hubble ever have dreamed that a space-based telescope that bears his name would continue his quest to precisely measure the universe's expansion rate?

The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center manages the telescope. The Space Telescope Science Institute (STScI) conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington, D.C.

The discovery is based on a joint Japan-New Zealand survey that scanned the center of the Milky Way galaxy during 2006 and 2007, revealing evidence for up to 10 free-floating planets roughly the mass of Jupiter. The isolated orbs, also known as orphan planets, are difficult to spot, and had gone undetected until now. The newfound planets are located at an average approximate distance of 10,000 to 20,000 light-years from Earth.

"Although free-floating planets have been predicted, they finally have been detected, holding major implications for planetary formation and evolution models," said Mario Perez, exoplanet program scientist at NASA Headquarters in Washington.

The discovery indicates there are many more free-floating Jupiter-mass planets that can't be seen. The team estimates there are about twice as many of them as stars. In addition, these worlds are thought to be at least as common as planets that orbit stars. This would add up to hundreds of billions of lone planets in our Milky Way galaxy alone.

"Our survey is like a population census," said David Bennett, a NASA and National Science Foundation-funded co-author of the study from the University of Notre Dame in South Bend, Ind. "We sampled a portion of the galaxy, and based on these data, can estimate overall numbers in the galaxy."

The study, led by Takahiro Sumi from Osaka University in Japan, appears in the May 19 issue of the journal Nature.

The survey is not sensitive to planets smaller than Jupiter and Saturn, but theories suggest lower-mass planets like Earth should be ejected from their stars more often. As a result, they are thought to be more common than free-floating Jupiters.

Previous observations spotted a handful of free-floating, planet-like objects within star-forming clusters, with masses three times that of Jupiter. But scientists suspect the gaseous bodies form more like stars than planets. These small, dim orbs, called brown dwarfs, grow from collapsing balls of gas and dust, but lack the mass to ignite their nuclear fuel and shine with starlight. It is thought the smallest brown dwarfs are approximately the size of large planets.

On the other hand, it is likely that some planets are ejected from their early, turbulent solar systems, due to close gravitational encounters with other planets or stars. Without a star to circle, these planets would move through the galaxy as our sun and other stars do, in stable orbits around the galaxy's center. The discovery of 10 free-floating Jupiters supports the ejection scenario, though it's possible both mechanisms are at play.

"If free-floating planets formed like stars, then we would have expected to see only one or two of them in our survey instead of 10," Bennett said. "Our results suggest that planetary systems often become unstable, with planets being kicked out from their places of birth."

The observations cannot rule out the possibility that some of these planets may have very distant orbits around stars, but other research indicates Jupiter-mass planets in such distant orbits are rare.

The survey, the Microlensing Observations in Astrophysics (MOA), is named in part after a giant wingless, extinct bird family from New Zealand called the moa. A 5.9-foot (1.8-meter) telescope at Mount John University Observatory in New Zealand is used to regularly scan the copious stars at the center of our galaxy for gravitational microlensing events. These occur when something, such as a star or planet, passes in front of another, more distant star. The passing body's gravity warps the light of the background star, causing it to magnify and brighten. Heftier passing bodies, like massive stars, will warp the light of the background star to a greater extent, resulting in brightening events that can last weeks. Small planet-size bodies will cause less of a distortion, and brighten a star for only a few days or less.

A second microlensing survey group, the Optical Gravitational Lensing Experiment (OGLE), contributed to this discovery using a 4.2-foot (1.3 meter) telescope in Chile. The OGLE group also observed many of the same events, and their observations independently confirmed the analysis of the MOA group.

NASA's Jet Propulsion Laboratory, Pasadena,Calif., manages NASA's Exoplanet Exploration program office. JPL is a division of the California Institute of Technology in Pasadena.

For more information visit http://www.nasa.gov/topics/universe/features/planet20110518.html

The findings offer new support for the favored theory of how dark energy works -- as a constant force, uniformly affecting the universe and propelling its runaway expansion. They contradict an alternate theory, where gravity, not dark energy, is the force pushing space apart. According to this alternate theory, with which the new survey results are not consistent, Albert Einstein's concept of gravity is wrong, and gravity becomes repulsive instead of attractive when acting at great distances.

"The action of dark energy is as if you threw a ball up in the air, and it kept speeding upward into the sky faster and faster," said Chris Blake of the Swinburne University of Technology in Melbourne, Australia. Blake is lead author of two papers describing the results that appeared in recent issues of the Monthly Notices of the Royal Astronomical Society. "The results tell us that dark energy is a cosmological constant, as Einstein proposed. If gravity were the culprit, then we wouldn't be seeing these constant effects of dark energy throughout time."

Dark energy is thought to dominate our universe, making up about 74 percent of it. Dark matter, a slightly less mysterious substance, accounts for 22 percent. So-called normal matter, anything with atoms, or the stuff that makes up living creatures, planets and stars, is only approximately four percent of the cosmos.

The idea of dark energy was proposed during the previous decade, based on studies of distant exploding stars called supernovae. Supernovae emit constant, measurable light, making them so-called "standard candles," which allows calculation of their distance from Earth. Observations revealed dark energy was flinging the objects out at accelerating speeds.

Dark energy is in a tug-of-war contest with gravity. In the early universe, gravity took the lead, dominating dark energy. At about 8 billion years after the Big Bang, as space expanded and matter became diluted, gravitational attractions weakened and dark energy gained the upper hand. Billions of years from now, dark energy will be even more dominant. Astronomers predict our universe will be a cosmic wasteland, with galaxies spread apart so far that any intelligent beings living inside them wouldn't be able to see other galaxies.

The new survey provides two separate methods for independently checking the supernovae results. This is the first time astronomers performed these checks across the whole cosmic timespan dominated by dark energy. The team began by assembling the largest three-dimensional map of galaxies in the distant universe, spotted by the Galaxy Evolution Explorer. The ultraviolet-sensing telescope has scanned about three-quarters of the sky, observing hundreds of millions of galaxies.

"The Galaxy Evolution Explorer helped identify bright, young galaxies, which are ideal for this type of study," said Christopher Martin, principal investigator for the mission at the California Institute of Technology in Pasadena. "It provided the scaffolding for this enormous 3-D map."

The astronomers acquired detailed information about the light for each galaxy using the Anglo-Australian Telescope and studied the pattern of distance between them. Sound waves from the very early universe left imprints in the patterns of galaxies, causing pairs of galaxies to be separated by approximately 500 million light-years.

This "standard ruler" was used to determine the distance from the galaxy pairs to Earth -- the closer a galaxy pair is to us, the farther apart the galaxies will appear from each other on the sky. As with the supernovae studies, this distance data were combined with information about the speeds at which the pairs are moving away from us, revealing, yet again, the fabric of space is stretching apart faster and faster.

The team also used the galaxy map to study how clusters of galaxies grow over time like cities, eventually containing many thousands of galaxies. The clusters attract new galaxies through gravity, but dark energy tugs the clusters apart. It slows down the process, allowing scientists to measure dark energy's repulsive force.

"Observations by astronomers over the last 15 years have produced one of the most startling discoveries in physical science; the expansion of the universe, triggered by the Big Bang, is speeding up," said Jon Morse, astrophysics division director at NASA Headquarters in Washington. "Using entirely independent methods, data from the Galaxy Evolution Explorer have helped increase our confidence in the existence of dark energy."

Caltech leads the Galaxy Evolution Explorer mission and is responsible for science operations and data analysis. NASA's Jet Propulsion Laboratory in Pasadena, manages the mission and built the science instrument. The mission was developed under NASA's Explorers Program managed by the Goddard Space Flight Center, Greenbelt, Md. Researchers sponsored by Yonsei University in South Korea and the Centre National d'Etudes Spatiales (CNES) in France collaborated on this mission. Caltech manages JPL for NASA.

For more information visit http://www.nasa.gov/mission_pages/galex/galex20110519.html

Among the new experiments flying will be several experiments, flown by NASA in cooperation with the Italian Space Agency, including one that looks at how the same kind of memory shape foam used in beds on Earth might be useful as a new kind of actuator, or servomechanism that supplies and transmits a measured amount of energy for mechanisms. The U.S.-Italian experiments also will look at cellular biology, radiation, plant growth and aging; how diet may affect night vision, and how an electronic device may be able used for air quality monitoring in spacecraft.

One NASA experiment known as Biology will use, among other items, C. elegans worms that are descendants of worms that survived the STS-107 space shuttle Columbia accident. The Rapid Turn Around engineering proof-of-concept test will use the Light Microscopy Microscope to look at three-dimensional samples of live organisms, tissue samples and fluorescent beads.

A NASA educational payload will deliver several toy Lego kits that can be assembled to form satellites, space shuttles and a scale model of the space station itself to demonstrate scientific concepts, and a Japan Aerospace Exploration Agency experiment called Try Zero-G that will help future astronauts show children the difference between microgravity and Earth gravity.

Research activities on the shuttle and station are integrated to maximize return during station assembly. The shuttle serves as a platform for completing short-duration research, while providing supplies and sample-return for ongoing research on station. For a full list of investigations available on this flight, see the STS-134 Press kit or visit http://www.nasa.gov.

For more information visit http://www.nasa.gov/mission_pages/station/research/news/sts134.html

Engineers at Vandenberg Air Force Base in California are performing final tests before mating Aquarius/SAC-D to its Delta II rocket. The mission is a collaboration between NASA and Argentina's space agency, Comision Nacional de Actividades Espaciales (CONAE), with participation from Brazil, Canada, France and Italy. SAC stands for Satelite de Applicaciones Cientificas. Aquarius was built by NASA's Jet Propulsion Laboratory in Pasadena, Calif., and the agency's Goddard Space Flight Center in Greenbelt, Md.

In addition to Aquarius, the observatory carries seven other instruments that will collect environmental data for a wide range of applications, including studies of natural hazards, air quality, land processes and epidemiology.

The mission will make NASA's first space observations of the concentration of dissolved salt at the ocean surface. Aquarius' observations will reveal how salinity variations influence ocean circulation, trace the path of freshwater around our planet, and help drive Earth's climate. The ocean surface constantly exchanges water and heat with Earth's atmosphere. Approximately 80 percent of the global water cycle that moves freshwater from the ocean to the atmosphere to the land and back to the ocean happens over the ocean.

Salinity plays a key role in these exchanges. By tracking changes in ocean surface salinity, Aquarius will monitor variations in the water cycle caused by evaporation and precipitation over the ocean, river runoff, and the freezing and melting of sea ice.

Salinity also makes seawater denser, causing it to sink, where it becomes part of deep, interconnected ocean currents. This deep ocean "conveyor belt" moves water masses and heat from the tropics to the polar regions, helping to regulate Earth's climate.

"Salinity is the glue that bonds two major components of Earth's complex climate system: ocean circulation and the global water cycle," said Aquarius Principal Investigator Gary Lagerloef of Earth & Space Research in Seattle. "Aquarius will map global variations in salinity in unprecedented detail, leading to new discoveries that will improve our ability to predict future climate."

Aquarius will measure salinity by sensing microwave emissions from the water's surface with a radiometer instrument. These emissions can be used to indicate the saltiness of the surface water, after accounting for other environmental factors. Salinity levels in the open ocean vary by only about five parts per thousand, and small changes are important. Aquarius uses advanced technologies to detect changes in salinity as small as about two parts per 10,000, equivalent to a pinch (about one-eighth of a teaspoon) of salt in a gallon of water.

Aquarius will map the entire open ocean every seven days for at least three years from 408 miles (657 kilometers) above Earth. Its measurements will produce monthly estimates of ocean surface salinity with a spatial resolution of 93 miles (150 kilometers). The data will reveal how salinity changes over time and from one part of the ocean to another.

The Aquarius/SAC-D mission continues NASA and CONAE's 17-year partnership. NASA provided launch vehicles and operations for three SAC satellite missions and science instruments for two.

JPL will manage Aquarius through its commissioning phase and archive mission data. Goddard will manage Aquarius mission operations and process science data. NASA's Launch Services Program at the agency's Kennedy Space Center in Florida is managing the launch.

CONAE is providing the SAC-D spacecraft, an optical camera, a thermal camera in collaboration with Canada, a microwave radiometer,; sensors from various Argentine institutions and the mission operations center there. France and Italy are contributing instruments.

For more information about Aquarius/SAC-D, visit: http://www.nasa.gov/aquarius and http://www.conae.gov.ar/eng/principal.html .

JPL is managed for NASA by the California Institute of Technology in Pasadena.

For more information visit http://www.nasa.gov/mission_pages/aquarius/news/aquarius20110517.html