Tracking the Origins of Speedy Space Particles

NASA's Time History of Events and Macroscale Interaction during Substorms (THEMIS) spacecraft combined with computer models have helped track the origin of the energetic particles in Earth's magnetic atmosphere that appear during a kind of space weather called a substorm. Understanding the source of such particles and how they are shuttled through Earth's atmosphere is crucial to better understanding the Sun's complex space weather system and thus protect satellites or even humans in space.

The results show that these speedy electrons gain extra energy from changing magnetic fields far from the origin of the substorm that causes them. THEMIS, which consists of five orbiting satellites, helped provide these insights when three of the spacecraft traveled through a large substorm on February 15, 2008. This allowed scientists to track changes in particle energy over a large distance. The observations were consistent with numerical models showing an increase in energy due to changing magnetic fields, a process known as betatron acceleration.

"The origin of fast electrons in substorms has been a puzzle," says Maha Ashour-Abdalla, the lead author of a Nature Physics paper that appeared online on January 30, 2011 on the subject and a physicist at the University of California, Los Angeles. "It hasn't been clear until now if they got their burst of speed in the middle of the storm, or from some place further away."

Substorms originate opposite the sun on Earth's "night side," at a point about a third of the distance to the moon. At this point in space, energy and particles from the solar wind store up over time. This is also a point where the more orderly field lines near Earth -- where they look like two giant ears on either side of the globe, a shape known as a dipole since the lines bow down to touch Earth at the two poles – can distort into long lines and sometimes pull apart and "reconnect." During reconnection, the stored energy is released in explosions that send particles out in all directions. But reconnection is a magnetic phenomenon and scientists don't know the exact mechanism that creates speeding particles from that phenomenon.

"For thirty years, one of the questions about the magnetic environment around Earth has been, 'how do magnetic fields give rise to moving, energetic particles?'" says NASA scientist Melvyn Goldstein, chief of the Geospace Physics Laboratory at NASA’s Goddard Space Flight Center in Greenbelt, Md., and another author on the paper. "We need to know such things to help plan the next generation of reconnection research instruments such as the Magnetospheric MultiScale mission (MMS) due to launch in 2014. MMS needs to look in the right place and for the correct signatures of particle energization."

In the early 1980s, scientists hypothesized that the quick, high-energy particles might get their speed from rapidly changing magnetic fields. Changing magnetic fields can cause electrons to zoom along a corkscrew path by the betatron effect.

Indeed, electrons moving toward Earth from a substorm will naturally cross a host of changing magnetic fields as those long, stretched field lines far away from Earth relax back to the more familiar dipole field lines closer to Earth, a process called dipolarization. Betatron acceleration causes the particles to gain energy and speed much farther away from the initial reconnection site. But in the absence of observations that could simultaneously measure data near the reconnection site and closer to Earth, the hypothesis was hard to prove or contradict.

THEMIS, however, was specifically designed to study the formation of substorms. It launched with five spacecraft, which can be spread out over some 44,000 miles – a perfect tool for examining different areas of Earth's magnetic environment at the same time. Near midnight, on February 15, 2008, three of the satellites moving through Earth's magnetic tail, about 36,000 miles from Earth, traveled through a large substorm.

"I looked at the THEMIS data for that substorm," says Ashour-Abdalla, "and saw there was a direct correlation of the increased particle energy at the origin with the region of dipolarization nearer to Earth."

To examine the data, Ashour-Abdalla and a team of researchers from UCLA, Nanchang University in China, NASA Goddard Space Flight Center, and the University of Maryland, Baltimore, used their expertise with computer modeling to simulate the complex dynamics that occur in space. The team began with spacecraft data from an ESA mission called Cluster that was in the solar wind at the time of the substorm. Using these observations of the solar environment, they modeled large scale electric and magnetic fields in space around Earth. Then they modeled the future fate of the various particles observed.

When the team looked at their models they saw that electrons near the reconnection sites didn't gain much energy. But as they looked closer to Earth, where the THEMIS satellites were located, their model showed particles that had some ten times as much energy – just as THEMIS had in fact observed.

This is consistent with the betatron acceleration model. The electrons gain a small amount of energy from the reconnection and then travel toward Earth, crossing many changing magnetic field lines. These fields produce betatronic acceleration just as Kivelson predicted in the early 1980s, speeding the electrons up substantially.

"This research shows the great science that can be accomplished when modelers, theorists and observationalists join forces," says astrophysicist Larry Kepko, who is a deputy project scientist for the THEMIS mission at Goddard. "THEMIS continues to yield critical insights into the dynamic processes that produce the space weather that affects Earth."

Launched in 2007, THEMIS was NASA's first five-satellite mission launched aboard a single rocket. The unique constellation of satellites provided scientists with data to help resolve the mystery of how Earth's magnetosphere stores and releases energy from the sun by triggering geomagnetic substorms. Two of the satellites have been renamed ARTEMIS and are in the process of moving to a new orbit around the moon. They are due to reach their final lunar orbit in July 2011. The three remaining THEMIS satellites continue to study substorms.

THEMIS is managed by NASA's Goddard Space Flight Center for the agency's Science Mission Directorate. The Space Sciences Laboratory at the University of California, Berkeley, is responsible for project management, space and ground-based instruments, mission integration, mission operations and science. ATK (formerly Swales Aerospace), Beltsville, Md., built the THEMIS probes. THEMIS is an international project conducted in partnership with Germany, France, Austria, and Canada.

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Asteroids Ahoy! Jupiter Scar Likely from Rocky Body

A hurtling asteroid about the size of the Titanic caused the scar that appeared in Jupiter's atmosphere on July 19, 2009, according to two papers published recently in the journal Icarus.

Data from three infrared telescopes enabled scientists to observe the warm atmospheric temperatures and unique chemical conditions associated with the impact debris. By piecing together signatures of the gases and dark debris produced by the impact shockwaves, an international team of scientists was able to deduce that the object was more likely a rocky asteroid than an icy comet. Among the teams were those led by Glenn Orton, an astronomer at NASA's Jet Propulsion Laboratory, Pasadena, Calif., and Leigh Fletcher, researcher at Oxford University, U.K., who started the work while he was a postdoctoral fellow at JPL.

"Both the fact that the impact itself happened at all and the implication that it may well have been an asteroid rather than a comet shows us that the outer solar system is a complex, violent and dynamic place, and that many surprises may be out there waiting for us," said Orton. "There is still a lot to sort out in the outer solar system."

The new conclusion is also consistent with evidence from results from NASA's Hubble Space Telescope indicating the impact debris in 2009 was heavier or denser than debris from comet Shoemaker-Levy 9, the last known object to hurl itself into Jupiter's atmosphere in 1994.

Before this collision, scientists had thought that the only objects that hit Jupiter were icy comets whose unstable orbits took them close enough to Jupiter to be sucked in by the giant planet's gravitational attraction. Those comets are known as Jupiter-family comets. Scientists thought Jupiter had already cleared most other objects, such as asteroids, from its sphere of influence. Besides Shoemaker-Levy, scientists know of only two other impacts in the summer of 2010, which lit up Jupiter's atmosphere.

The July 19, 2009 object likely hit Jupiter between 9 a.m. and 11 a.m. UTC. Amateur astronomer Anthony Wesley from Australia was the first to notice the scar on Jupiter, which appeared as a dark spot in visible wavelengths. The scar appeared at mid-southern latitudes. Wesley tipped off Orton and colleagues, who immediately used existing observing time at NASA's Infrared Telescope Facility in Mauna Kea, Hawaii, the following night and proposed observing time on a host of other ground-based observatories, including the Gemini North Observatory in Hawaii, the Gemini South Telescope in Chile, and the European Southern Observatory's Very Large Telescope in Chile. Data were acquired at regular intervals during the week following the 2009 collision.

The data showed that the impact had warmed Jupiter's lower stratosphere by as much as 3 to 4 Kelvin at about 42 kilometers above its cloudtops. Although 3 to 4 Kelvin does not sound like a lot, it is a significant deposition of energy because it is spread over such an enormous area.

Plunging through Jupiter's atmosphere, the object created a channel of super-heated atmospheric gases and debris. An explosion deep below the clouds – probably releasing at least around 200 trillion trillion ergs of energy, or more than 5 gigatons of TNT -- then launched debris material back along the channel, above the cloud tops, to splash back down into the atmosphere, creating the aerosol particulates and warm temperatures observed in the infrared. The blowback dredged up ammonia gas and other gases from a lower part of the atmosphere known as the troposphere into a higher part of the atmosphere known as the stratosphere.

"Comparisons between the 2009 images and the Shoemaker-Levy 9 results are beginning to show intriguing differences between the kinds of objects that hit Jupiter," Fletcher said. "The dark debris, the heated atmosphere and upwelling of ammonia were similar for this impact and Shoemaker-Levy, but the debris plume in this case didn't reach such high altitudes, didn't heat the high stratosphere, and contained signatures for hydrocarbons, silicates and silicas that weren't seen before. The presence of hydrocarbons, and the absence of carbon monoxide, provide strong evidence for a water-depleted impactor in 2009."

The detection of silica in this mixture of Jovian atmospheric gases, processed bits from the impactor and byproducts of high-energy chemical reactions was significant because abundant silica could only be produced in the impact itself, by a strong rocky body capable of penetrating very deeply into the Jovian atmosphere before exploding, but not by a much weaker comet nucleus. Assuming that the impactor had a rock-like density of around 2.5 grams per cubic centimeter (160 pounds per cubic foot), scientists calculated a likely diameter of 200 to 500 meters (700 to 1,600 feet).

Scientists computed the set of possible orbits that would bring an object into Jupiter in the right range of times and at the right locations. Then they searched the catalog of known asteroids and comets to find the kinds of objects in these orbits. An object named 2005 TS100 – which is probably an asteroid but could be an extinct comet – was one of the closest matches. Although this object was not the actual impactor, it has a very chaotic orbit and made several very close approaches to Jupiter in computer models, demonstrating that an asteroid could have hurtled into Jupiter.

"We weren't expecting to find that an asteroid was the likely culprit in this impact, but we've now learned Jupiter is getting hit by a diversity of objects," said Paul Chodas, a scientist at NASA's Near-Earth Object Program Office at JPL. " Asteroid impacts on Jupiter were thought to be quite rare compared to impacts from the so-called 'Jupiter-family comets,' but now it seems there may be a significant population of asteroids in this category."

Scientists are still working to figure out what that frequency at Jupiter is, but asteroids of this size hit Earth about once every 100,000 years. The next steps in this investigation will be to use detailed simulations of the impact to refine the size and properties of the impactor, and to continue to use imaging at infrared, as well as visible wavelengths, to search for debris from future impacts of this size or smaller.

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

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Runaway Star Plows Through Space

A massive star flung away from its former companion is plowing through space dust. The result is a brilliant bow shock, seen here as a yellow arc in a new image from NASA's Wide-field Infrared Survey Explorer, or WISE.

The star, named Zeta Ophiuchi, is huge, with a mass of about 20 times that of our sun. In this image, in which infrared light has been translated into visible colors we see with our eyes, the star appears as the blue dot inside the bow shock.

Zeta Ophiuchi once orbited around an even heftier star. But when that star exploded in a supernova, Zeta Ophiuchi shot away like a bullet. It's traveling at a whopping 54,000 miles per hour (or 24 kilometers per second), and heading toward the upper left area of the picture.

As the star tears through space, its powerful winds push gas and dust out of its way and into what is called a bow shock. The material in the bow shock is so compressed that it glows with infrared light that WISE can see. The effect is similar to what happens when a boat speeds through water, pushing a wave in front of it.

This bow shock is completely hidden in visible light. Infrared images like this one from WISE are therefore important for shedding new light on the region.

JPL manages and operates WISE for NASA's Science Mission Directorate, Washington. The principal investigator, Edward Wright, is at UCLA. The mission was competitively selected under NASA's Explorers Program managed by NASA's Goddard Space Flight Center, Greenbelt, Md. The science instrument was built by the Space Dynamics Laboratory, Logan, Utah, and the spacecraft was built by Ball Aerospace & Technologies Corp., Boulder, Colo. Science operations and data processing take place at the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena. Caltech manages JPL for NASA.

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WORF First Image Web Feature

A test photo of British Columbia's snow-capped west coast mountains is the first official image taken from the International Space Station's new Window Observational Research Facility, or WORF.

The image was taken to test the functionality of the control computer and camera associated with EarthKAM, an educational outreach project that allows Earth bound middle school students to take pictures of our home planet from the unique perspective of the space station, 220 miles above the Earth's surface. WORF was delivered to the station on the STS-131 mission of space shuttle Discovery in April 2010.

EarthKAM uses a Nikon D2X digital camera, and was set up in the WORF by Expedition 26 NASA flight engineer Cady Coleman on Jan. 17. EarthKAM ground controllers took the test photo. Expedition 26 also includes Commander Scott Kelly of NASA, European Space Agency astronaut Paolo Nespoli, and Russian cosmonauts Oleg Skripochka, Alexander Kaleri and Dmitry Kontratyev.

The test photo, designated ISS EarthKAM Image Winter 2011 #9362, is of an area of British Columbia, Canada, just north of Vancouver Island. The center point of the photo is 51 degrees, 48 minutes north and 127 degrees, 54 minutes west. Visible in the photo are Calvert and Hecate Islands on the Canadian coast and the southern portion of Hunter Island. Also visible are glaciers of the Ha-iltzuk Icefield near the 8,720-foot-tall -- 2,658-meter-tall -- Mount Somolenko. Mount Somolenko is a volcanic peak in southwestern British Columbia, that lies in a circular volcanic depression in the Pacific Ranges of the Coast Mountains called the Silverthrone Caldera.

While this isn't a particularly unique Earth observation image, it is notable that even though it was taken with a wider angle, 50mm lens and covers an area 124 miles/200 kilometers, by 83 miles/134 kilometers, it can be enlarged by more than 400 percent while keeping features in the photo identifiable. This is made possible by the high-quality optics of the Earth-facing window of the Destiny Laboratory, which was launched on Feb. 7, 2001.

The installation of WORF allowed removal of an internal "scratch pane" that has reduced the quality of images taken though the window. WORF also provides a highly stable mounting platform to hold cameras and sensors rock steady at the window, as well as the power, command, data, and cooling connections needed for their operation.

"With the WORF finally in place we can now for the first time make full use of the investment we made in having an optical quality window onboard the station for Earth science and observation," said former astronaut Mario Runco, who was part of the design and development teams for the Destiny window and WORF, and now serves as NASA's lead for Spacecraft Window Optics and Window/WORF Utilization at NASA's Johnson Space Center, Houston.

"We are very excited to have a new camera system that appears to be functional and taking incredible images," said Karen Flammer, who manages EarthKAM operations at the University of California, can Diego. "The first student images were taken by Parkview Montessori in the Jackson-Madison County (Tenn.) School System, and Public School 229 - Dyker in Brooklyn, N.Y., part of the New York City Department of Education.

Parkview teacher Vickie LeCroy's students plan to study landforms, such as islands, mountains and deserts in the image they took of Mexico, and Dyker teacher Camille Fratantoni’s students plan to enrich their studies of earth science and learn more about NASA missions.

In addition to their educational outreach role with EarthKAM, the combination of the window and WORF adds to the station's capabilities as an Earth science remote sensing platform for high-resolution cameras and multi and hyperspectral imagers. Images from space have many applications, such as in the study of climate and meteorology; oceanography; geology and volcanology; coastal, agricultural, ranch and forestry management; and disaster assessments and management.

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The Two-faced Whirlpool Galaxy

These images by NASA's Hubble Space Telescope show off two dramatically different face-on views of the spiral galaxy M51, dubbed the Whirlpool Galaxy.

The image at left, taken in visible light, highlights the attributes of a typical spiral galaxy, including graceful, curving arms, pink star-forming regions, and brilliant blue strands of star clusters.

In the image at right, most of the starlight has been removed, revealing the Whirlpool's skeletal dust structure, as seen in near-infrared light. This new image is the sharpest view of the dense dust in M51. The narrow lanes of dust revealed by Hubble reflect the galaxy's moniker, the Whirlpool Galaxy, as if they were swirling toward the galaxy's core.

To map the galaxy's dust structure, researchers collected the galaxy's starlight by combining images taken in visible and near-infrared light. The visible-light image captured only some of the light; the rest was obscured by dust. The near-infrared view, however, revealed more starlight because near-infrared light penetrates dust. The researchers then subtracted the total amount of starlight from both images to see the galaxy's dust structure.

The red color in the near-infrared image traces the dust, which is punctuated by hundreds of tiny clumps of stars, each about 65 light-years wide. These stars have never been seen before. The star clusters cannot be seen in visible light because dense dust enshrouds them. The image reveals details as small as 35 light-years across.

Astronomers expected to see large dust clouds, ranging from about 100 light-years to more than 300 light-years wide. Instead, most of the dust is tied up in smooth and diffuse dust lanes. An encounter with another galaxy may have prevented giant clouds from forming.

Probing a galaxy's dust structure serves as an important diagnostic tool for astronomers, providing invaluable information on how the gas and dust collapse to form stars. Although Hubble is providing incisive views of the internal structure of galaxies such as M51, the planned James Webb Space Telescope (JWST) is expected to produce even crisper images.

Researchers constructed the image by combining visible-light exposures from Jan. 18 to 22, 2005, with the Advanced Camera for Surveys (ACS), and near-infrared light pictures taken in December 2005 with the Near Infrared Camera and Multi-Object Spectrometer (NICMOS).

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Gardening in Space with HydroTropi

Plants are fundamental to life on Earth, converting light and carbon dioxide into food and oxygen. Plant growth may be an important part of human survival in exploring space, as well. Gardening in space has been part of the International Space Station from the beginning -- whether peas grown in the Lada greenhouse or experiments in the Biomass Production System. The space station offers unique opportunities to study plant growth and gravity, something that cannot be done on Earth.

The latest experiment that has astronauts putting their green thumbs to the test is Hydrotropism and Auxin-Inducible Gene expression in Roots Grown Under Microgravity Conditions, known as HydroTropi. Operations were conducted October 18-21, 2010, HydroTropi is a Japan Aerospace Exploration Agency (JAXA)-run study that looks at directional root growth. In microgravity, roots grow latterly or sideways, instead of up and down like they do under Earth’s gravitational forces.

Using cucumber plants (scientific name Cucumis sativus), investigators look to determine whether hydrotropic -- plant root orientation due to water—response can control the direction of root growth in microgravity. To perform the HydroTropi experiment, astronauts transport the cucumber seeds from Earth to the space station and then coax them into growth. The seeds, which reside in Hydrotropism chambers, undergo 18 hours of incubation in a Cell Biology Experiment Facility or CBEF. Then the crewmembers activate the seeds with water or a saturated salt solution, followed by a second application of water 4 to 5 hours later. The crew harvests the cucumber seedlings and preserves them using fixation tubes called Kenney Space Center Fixation Tubes or KFTs, which then store in one of the station MELFI freezers to await return to Earth.

The results from HydroTropi, which returns to Earth on STS-133, will help investigators to better understand how plants grow and develop at a molecular level. The experiment will demonstrate a plant’s ability to change growth direction in response to gravity (gravitropism) vs. directional growth in response to water (hydrotropism). By looking at the reaction of the plants to the stimuli and the resulting response of differential auxin -- the compound regulating the growth of plants -- investigators will learn about plants inducible gene expression. In space, investigators hope HydroTropi will show them how to control directional root growth by using the hydrotropism stimulus; this knowledge may also lead to significant advancements in agriculture production on Earth.

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A First Look at Flight in 2025

In late 2010, NASA awarded contracts to three teams — Lockheed Martin, Northrop Grumman, The Boeing Company — to study advanced concept designs for aircraft that could take to the skies in the year 2025.

At the time of the award, the team gave NASA a sneak peek of the particular design they plan to pursue.

Each design looks very different, but all final designs have to meet NASA's goals for less noise, cleaner exhaust and lower fuel consumption. Each aircraft has to be able to do all of those things at the same time, which requires a complex dance of tradeoffs between all of the new advanced technologies that will be on these vehicles.

The proposed aircraft will also have to operate safely in a more modernized air traffic management system.

And each design has to fly up to 85 percent of the speed of sound; cover a range of approximately 7,000 miles; and carry between 50,000 and 100,000 pounds of payload, either passengers or cargo.

For the rest of this year, each team will be exploring, testing, simulating, keeping and discarding innovations and technologies to make their design a winner.

How different will the final designs look from these initial glimpses?

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NASA's Hubble Finds that Puny Stars Pack a Big Punch

A deep survey of more than 200,000 stars in our Milky Way galaxy has unveiled the sometimes petulant behavior of tiny red dwarf stars. These stars, which are smaller than the Sun, can unleash powerful eruptions called flares that may release the energy of more than 100 million atomic bombs.

Red dwarfs are the most abundant stars in our universe and are presumably hosts to numerous planets. However, their erratic behavior could make life unpleasant, if not impossible, for many alien worlds. Flares are sudden eruptions of heated plasma that occur when powerful magnetic field lines in a star's atmosphere "reconnect," snapping like a rubber band and releasing vast amounts of energy. When they occur, flares would blast any planets orbiting the star with ultraviolet light, bursts of X-rays, and a gush of charged particles called a stellar wind.

Studying the light from 215,000 red dwarfs collected in observations by NASA's Hubble Space Telescope, astronomers found 100 stellar flares. The observations, taken over a seven-day period, constitute the largest continuous monitoring of red dwarf stars ever undertaken.

"We know that hyperactive young stars produce flares, but this study shows that even in fairly old stars that are several billion years old, flares are a fact of life," says astronomer Rachel Osten of the Space Telescope Science Institute in Baltimore, Md., leader of the research team. "Life could be rough for any planets orbiting close enough to these flaring stars. Their heated atmospheres could puff up and might get stripped away."

Osten and her team, including Adam Kowalski of the University of Washington in Seattle, found that the red dwarf stars flared about 15 times less frequently than in previous surveys, which observed younger and less massive stars.

The stars in this study were originally part of a search for planets. Hubble monitored the stars continuously for a week in 2006, looking for the signature of planets passing in front of them. The stars were photographed by Hubble's Advanced Camera for Surveys during the extrasolar-planet survey called the Sagittarius Window Eclipsing Extrasolar Planet Search (SWEEPS).

Osten and Kowalski realized that this powerful census contained important information on the stars themselves, and they took advantage of it. They searched the Hubble data, looking for a slight increase in the brightness of red dwarfs, a signature of flares. Some of the stars grew up to 10 percent brighter over a short period of time, which is actually much brighter than flares on our Sun. The average duration of the flares was 15 minutes. A few stars produced multiple flares.

The astronomers found that stars that periodically oscillate in brightness, called variable stars, were more prone to the short-term outbursts.

"We discovered that variable stars are about a thousand times more likely to flare than non-variable stars," Kowalski says. "The variable stars are rotating fast, which may mean they are in rapidly orbiting binary systems. If the stars possess large star spots, dark regions on a star's surface, that will cause the star's light to vary when the spots rotate in and out of view. Star spots are produced when magnetic field lines poke through the surface. So, if there are big spots, there is a large area covered by strong magnetic fields, and we found that those stars had more flares."

Although red dwarfs are smaller than the Sun, they have a deeper convection zone, where cells of hot gas bubble to the surface, like boiling oatmeal," Osten explains. This zone generates the magnetic field and enables red dwarfs to put out such energetic flares.

"The red dwarfs also have magnetic fields that are stronger than the Sun's," Osten continues. "They cover a much larger area than the Sun. Sunspots cover less than 1 percent of the Sun's surface, while red dwarfs can have star spots that cover half of their surfaces."

Kowalski will present the team's results on Jan. 10, 2011, at the American Astronomical Society meeting in Seattle, Wash.

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

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NASA'S Kepler Mission Discovers Its First Rocky Planet

NASA's Kepler mission confirmed the discovery of its first rocky planet, named Kepler-10b. Measuring 1.4 times the size of Earth, it is the smallest planet ever discovered outside our solar system.

The discovery of this so-called exoplanet is based on more than eight months of data collected by the spacecraft from May 2009 to early January 2010.

"All of Kepler's best capabilities have converged to yield the first solid evidence of a rocky planet orbiting a star other than our sun," said Natalie Batalha, Kepler's deputy science team lead at NASA's Ames Research Center in Moffett Field, Calif., and primary author of a paper on the discovery accepted by the Astrophysical Journal. "The Kepler team made a commitment in 2010 about finding the telltale signatures of small planets in the data, and it's beginning to pay off."

Kepler's ultra-precise photometer measures the tiny decrease in a star's brightness that occurs when a planet crosses in front of it. The size of the planet can be derived from these periodic dips in brightness. The distance between the planet and the star is calculated by measuring the time between successive dips as the planet orbits the star.

Kepler is the first NASA mission capable of finding Earth-size planets in or near the habitable zone, the region in a planetary system where liquid water can exist on the planet's surface. However, since it orbits once every 0.84 days, Kepler-10b is more than 20 times closer to its star than Mercury is to our sun and not in the habitable zone.

Kepler-10 was the first star identified that could potentially harbor a small transiting planet, placing it at the top of the list for ground-based observations with the W.M. Keck Observatory 10-meter telescope in Hawaii.

Scientists waiting for a signal to confirm Kepler-10b as a planet were not disappointed. Keck was able to measure tiny changes in the star's spectrum, called Doppler shifts, caused by the telltale tug exerted by the orbiting planet on the star.

"The discovery of Kepler-10b, a bona fide rocky world, is a significant milestone in the search for planets similar to our own," said Douglas Hudgins, Kepler program scientist at NASA Headquarters in Washington. "Although this planet is not in the habitable zone, the exciting find showcases the kinds of discoveries made possible by the mission and the promise of many more to come," he said.

"Our knowledge of the planet is only as good as the knowledge of the star it orbits," said Batalha. Because Kepler-10 is one of the brighter stars being targeted by Kepler, scientists were able to detect high frequency variations in the star's brightness generated by stellar oscillations, or starquakes. "This is the analysis that really allowed us to pin down Kepler-10b's properties.," she added.

"We have a clear signal in the data arising from light waves that travel within the interior of the star," said Hans Keldsen, an astronomer at the Kepler Asteroseismic Science Consortium at Aarhus University in Denmark. Kepler Asteroseismic Science Consortium scientists use the information to better understand the star, just as earthquakes are used to learn about Earth's interior structure. "As a result of this analysis, Kepler-10 is one of the most well characterized planet-hosting stars in the universe next to our sun," Kjeldsen said.

That's good news for the team studying Kepler-10b. Accurate stellar properties yield accurate planet properties. In the case of Kepler-10b, the picture that emerges is of a rocky planet with a mass 4.6 times that of Earth and with an average density of 8.8 grams per cubic centimeter -- similar to that of an iron dumbbell.

"This planet is unequivocally rocky, with a surface you could stand on," commented team member Dimitar Sasselov, of the Harvard-Smithsonian Center for Astrophysics in Cambridge and a Kepler co-investigator.

"All of Kepler’s best capabilities have converged for this discovery," Batalha said, "yielding the first solid evidence of a rocky planet orbiting a star other than our sun."

Ames manages Kepler's ground system development, mission operations and science data analysis. NASA's Jet Propulsion Laboratory in Pasadena, Calif., managed Kepler mission development.

Ball Aerospace and Technologies Corp. in Boulder, Colo., developed the Kepler flight system and supports mission operations with the Laboratory for Atmospheric and Space Physics at the University of Colorado in Boulder. The Space Telescope Science Institute in Baltimore archives, hosts and distributes the Kepler science data.

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

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NASA Image Shows La Niña-Caused Woes Down Under

The current La Nina in the Pacific Ocean, one of the strongest in the past 50 years, continues to exert a powerful influence on weather around the world, affecting rainfall and temperatures in varying ways in different locations.

For Australia, La Nina typically means above-average rains, and the current La Nina is no exception. Heavy rains that began in late December led to the continent's worst flooding in nearly a half century, at its peak inundating an area the size of Germany and France combined. The Associated Press reports about 1,200 homes in 40 communities are underwater and about 11,000 others are damaged, resulting in thousands of evacuations and 10 deaths to date.

On Jan. 7, 2010, the Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER) instrument on NASA's Terra spacecraft captured this image of the inundated city of Rockhampton, Queensland, Australia. With a population of 75,000, Rockhampton is the largest city affected by the current flooding. Torrential rains in northeastern Australia caused the Fitzroy River to overflow its banks and flood much of the city and surrounding agricultural lands. Both the airport and major highways are underwater, isolating the city.

In this natural color rendition, muddy water is brown, and shallow, clearer water is gray. Vegetation is depicted in various shades of green, and buildings and streets are white. The image is located at 23.3 degrees south latitude, 150.5 degrees east longitude, and covers an area of 22 by 28.1 kilometers (13.6 by 17.4 miles).

For more information visit http://www.nasa.gov/topics/earth/features/lanina20110107.html

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Andromeda is So Hot 'n' Cold

This mosaic of the Andromeda spiral galaxy highlights explosive stars in its interior, and cooler, dusty stars forming in its many rings. The image is a combination of observations from the Herschel Space Observatory taken in infrared light (seen in orange hues), and the XMM-Newton telescope captured in X-rays (seen in blues). NASA plays a role in both of these European Space Agency-led missions.

Herschel provides a detailed look at the cool clouds of star birth that line the galaxy's five concentric rings. Massive young stars are heating blankets of dust that surround them, causing them to glow in the longer-wavelength infrared light, known as far-infrared, that Herschel sees.

In contrast, XMM-Newton is capturing what happens at the end of the lives of massive stars. It shows the high-energy X-rays that come from, among other objects, supernova explosions and massive dead stars rotating around companions. These X-ray sources are clustered in the center of the galaxy, where the most massive stars tend to form.

Andromeda is our Milky Way galaxy's nearest large neighbor. It is located about 2.5 million light-years away and holds up to an estimated trillion stars. Our Milky Way is thought to contain about 200 billion to 400 billion stars.

Herschel is a European Space Agency cornerstone mission, with science instruments provided by consortia of European institutes and with important participation by NASA. NASA's Herschel Project Office is based at NASA's Jet Propulsion Laboratory, Pasadena, Calif. JPL contributed mission-enabling technology for two of Herschel's three science instruments. The NASA Herschel Science Center, part of the Infrared Processing and Analysis Center at the California Institute of Technology in Pasadena, supports the United States astronomical community. Caltech manages JPL for NASA.

For more information visit http://www.nasa.gov/mission_pages/herschel/herschel20110105.html

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Rover Will Spend 7th Birthday at Stadium-Size Crater

The High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter captured a Dec. 31, 2010, view of the Mars Exploration Rover Opportunity on the southwestern rim of a football-field-size crater called "Santa Maria."

Opportunity arrived at the western edge of Santa Maria crater in mid-December and will spend about two months investigating rocks there. That investigation will take Opportunity into the beginning of its eighth year on Mars. Opportunity landed in the Meridiani Planum region of Mars on Jan. 25, 2004, Universal Time (Jan. 24, Pacific Time) for a mission originally planned to last for three months.

Opportunity and its twin, Spirit, which passed its seventh anniversary on Mars this week, both have made important discoveries about wet environments on ancient Mars that may have been favorable for supporting microbial life.

NASA's Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the Mars Reconnaissance Orbiter and Mars Exploration Rover projects for NASA's Science Mission Directorate, Washington. Lockheed Martin Space Systems, Denver, built the orbiter. The University of Arizona, Tucson, operates the HiRISE camera, which was built by Ball Aerospace & Technologies Corp., Boulder, Colo.

For more information visit http://www.nasa.gov/mission_pages/MRO/news/mro20110104.html

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