The galaxy, which is known as Markarian 739 or NGC 3758, lies 425 million light-years away toward the constellation Leo. Only about 11,000 light-years separate the two cores, each of which contains a black hole gorging on infalling gas.

The study will appear in a forthcoming issue of The Astrophysical Journal Letters.

"At the hearts of most large galaxies, including our own Milky Way, lies a supermassive black hole weighing millions of times the sun's mass," said Michael Koss, the study's lead author at NASA's Goddard Space Flight Center in Greenbelt, Md., and the University of Maryland in College Park (UMCP). "Some of them radiate billions of times as much energy as the sun."

Astronomers refer to galaxy centers exhibiting such intense emission as active galactic nuclei (AGN). Yet as common as monster black holes are, only about one percent of them are currently powerful AGN. Binary AGN are rarer still: Markarian 739 is only the second identified within half a billion light-years.

Many scientists think that disruptive events like galaxy collisions trigger AGN to switch on by sending large amounts of gas toward the black hole. As the gas spirals inward, it becomes extremely hot and radiates huge amounts of energy.

Since 2004, the Burst Alert Telescope (BAT) aboard Swift has been mapping high-energy X-ray sources all around the sky. The survey is sensitive to AGN up to 650 million light-years away and has uncovered dozens of previously unrecognized systems. Follow-up studies by Koss and colleagues published in 2010 reveal that about a quarter of the Swift BAT AGN were either interacting or in close pairs, with perhaps 60 percent of them poised to merge in another billion years.

"If two galaxies collide and each possesses a supermassive black hole, there should be times when both black holes switch on as AGN," said coauthor Richard Mushotzky, professor of astronomy at UMCP. "We weren't seeing many double AGN, so we turned to Chandra for help."

Swift's BAT instrument is scanning one-tenth of the sky at any given moment, its X-ray survey growing more sensitive every year as its exposure increases. Where Swift's BAT provided a wide-angle view, the X-ray telescope aboard the Chandra X-ray Observatory acted like a zoom lens and resolved details a hundred times smaller.

For decades, astronomers have known that the eastern nucleus of Markarian 739 contains a black hole that is actively accreting matter and generating prodigious energy. The Chandra study shows that its western neighbor is too. This makes the galaxy one of the nearest and clearest cases of a binary AGN.

The distance separating the two black holes is about a third of the distance separating the solar system from the center of our own galaxy. The dual AGN of Markarian 739 is the second-closest known, both in terms of distance from one another and distance from Earth. However, another galaxy known as NGC 6240 holds both records.

How did the second AGN remain hidden for so long? "Markarian 739 West shows no evidence of being an AGN in visible, ultraviolet and radio observations," said coauthor Sylvain Veilleux, a professor of astronomy at UMCP. "This highlights the critical importance of high-resolution observations at high X-ray energies in locating binary AGN."

The research team also includes Ezequiel Treister and David Sanders at the University of Hawaii’s Institute for Astronomy in Honolulu, Kevin Schawinski at Yale University in New Haven, Conn., and Ranjan Vasudevan, Neal Miller and Margaret Trippe at the University of Maryland, College Park.

Swift, launched in November 2004, is managed by Goddard. It was built and is being operated in collaboration with Penn State University, the Los Alamos National Laboratory in New Mexico, and General Dynamics in Falls Church, Va.; the University of Leicester and Mullard Space Sciences Laboratory in the United Kingdom; Brera Observatory and the Italian Space Agency in Italy; plus additional partners in Germany and Japan.

The Marshall Space Flight Center manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory controls Chandra's science and flight operations from Cambridge, Mass.

For more information visit http://www.nasa.gov/mission_pages/swift/bursts/monster-black-holes.html

The STEREO spacecraft reached opposition (180° separation) on February 6 but part of the sun was inaccessible to their combined view until June 1. This image represents the first day when the entire far side could be seen.

The image is aligned so that solar north is directly up. The seam between the two images is inclined because the plane of Earth’s -- and STEREO's -- orbit, known as the "ecliptic", is inclined with respect to the sun's axis of rotation. The data was collected by STEREO's Extreme Ultraviolet Imagers in the SECCHI instrument suites.

STEREO was built and is operated for NASA by the Applied Physical Laboratory of the Johns Hopkins University; the spacecraft were launched on October 25, 2006 aboard a Delta II. The SECCHI instrument suite is a collaboration led by the Naval Research Laboratory, and the EUVI instruments were built by the Lockheed Martin Solar and Astrophysics Laboratory.

For more information visit http://www.nasa.gov/mission_pages/stereo/news/farside-060111.html

Mission scientists say the probes have just sent back some very big news indeed.

It's bubbly out there.

According to computer models, the bubbles are large, about 100 million miles wide, so it would take the speedy probes weeks to cross just one of them. Voyager 1 entered the "foam-zone" around 2007, and Voyager 2 followed about a year later. At first researchers didn't understand what the Voyagers were sensing--but now they have a good idea.

"The sun's magnetic field extends all the way to the edge of the solar system," explains Opher. "Because the sun spins, its magnetic field becomes twisted and wrinkled, a bit like a ballerina's skirt. Far, far away from the sun, where the Voyagers are now, the folds of the skirt bunch up."

When a magnetic field gets severely folded like this, interesting things can happen. Lines of magnetic force criss-cross, and "reconnect". (Magnetic reconnection is the same energetic process underlying solar flares.) The crowded folds of the skirt reorganize themselves, sometimes explosively, into foamy magnetic bubbles.

"We never expected to find such a foam at the edge of the solar system, but there it is!" says Opher's colleague, University of Maryland physicist Jim Drake.

Theories dating back to the 1950s had predicted a very different scenario: The distant magnetic field of the sun was supposed to curve around in relatively graceful arcs, eventually folding back to rejoin the sun. The actual bubbles appear to be self-contained and substantially disconnected from the broader solar magnetic field.

Energetic particle sensor readings suggest that the Voyagers are occasionally dipping in and out of the foam—so there might be regions where the old ideas still hold. But there is no question that old models alone cannot explain what the Voyagers have found.

Says Drake: "We are still trying to wrap our minds around the implications of these findings."

The structure of the sun's distant magnetic field—foam vs. no-foam—is of acute scientific importance because it defines how we interact with the rest of the galaxy. Researchers call the region where the Voyagers are now "the heliosheath." It is essentially the border crossing between the Solar System and the rest of the Milky Way. Lots of things try to get across—interstellar clouds, knots of galactic magnetism, cosmic rays and so on. Will these intruders encounter a riot of bubbly magnetism (the new view) or graceful lines of magnetic force leading back to the sun (the old view)?

The case of cosmic rays is illustrative. Galactic cosmic rays are subatomic particles accelerated to near-light speed by distant black holes and supernova explosions. When these microscopic cannonballs try to enter the solar system, they have to fight through the sun's magnetic field to reach the inner planets.

"The magnetic bubbles appear to be our first line of defense against cosmic rays," points out Opher. "We haven't figured out yet if this is a good thing or not."

On one hand, the bubbles would seem to be a very porous shield, allowing many cosmic rays through the gaps. On the other hand, cosmic rays could get trapped inside the bubbles, which would make the froth a very good shield indeed.

So far, much of the evidence for the bubbles comes from the Voyager energetic particle and flow measurements. Proof can also be obtained from the Voyager magnetic field observations and some of this data is also very suggestive. However, because the magnetic field is so weak, the data takes much longer to analyze with the appropriate care. Thus, unraveling the magnetic signatures of bubbles in the Voyager data is ongoing.

"We'll probably discover which is correct as the Voyagers proceed deeper into the froth and learn more about its organization," says Opher. "This is just the beginning, and I predict more surprises ahead."

For more information visit http://www.nasa.gov/mission_pages/voyager/heliosphere-surprise.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

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

"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

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 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

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

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

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