L'espace par l'image

Artist Concept: Space Launch System Takes Flight
Artist concept of NASA’s Space Launch System (SLS) 70-metric-ton configuration launching to space. SLS will be the most powerful rocket ever built for deep space missions, including to an asteroid and ultimately to Mars. The first SLS mission -- Exploration Mission 1 -- will launch an uncrewed Orion spacecraft to a stable orbit beyond the moon and bring it back to Earth to demonstrate the integrated system performance of the SLS rocket and Orion spacecraft’s re-entry and landing prior to a crewed flight.

25 Years Ago, Voyager 2 Captures Images of Neptune
NASA's Voyager 2 spacecraft gave humanity its first glimpse of Neptune and its moon Triton in the summer of 1989. This picture of Neptune was produced from the last whole planet images taken through the green and orange filters on the Voyager 2 narrow angle camera. The images were taken on Aug. 20, 1989, at a range of 4.4 million miles from the planet, 4 days and 20 hours before closest approach on Aug. 25. The picture shows the Great Dark Spot and its companion bright smudge; on the west limb the fast moving bright feature called "Scooter" and the little dark spot are visible. These clouds were seen to persist for as long as Voyager's cameras could resolve them. North of these, a bright cloud band similar to the south polar streak may be seen.
In the summer of 2015, another NASA mission to the farthest zone of the solar system, New Horizons, will make a historic first close-up study of Pluto. Although a fast flyby, New Horizons' Pluto encounter on July 14, 2015, will not be a replay of Voyager but more of a sequel and a reboot, with a new and more technologically advanced spacecraft and, more importantly, a new cast of characters. Those characters are Pluto and its family of five known moons, all of which will be seen up close for the first time next summer.
Image Credit: NASA

This artist’s concept shows the immediate aftermath of a large asteroid impact around NGC 2547-ID8, a 35-million-year-old sun-like star. NASA's Spitzer Space Telescope witnessed a giant surge in dust around the star, likely the result of two asteroids colliding.
Image Credit: 
NASA/JPL-Caltech

NASA's Spitzer Space Telescope has spotted an eruption of dust around a young star, possibly the result of a smashup between large asteroids. This type of collision can eventually lead to the formation of planets.
Scientists had been regularly tracking the star, called NGC 2547-ID8, when it surged with a huge amount of fresh dust between August 2012 and January 2013.
"We think two big asteroids crashed into each other, creating a huge cloud of grains the size of very fine sand, which are now smashing themselves into smithereens and slowly leaking away from the star," said lead author and graduate student Huan Meng of the University of Arizona, Tucson.
While dusty aftermaths of suspected asteroid collisions have been observed by Spitzer before, this is the first time scientists have collected data before and after a planetary system smashup. The viewing offers a glimpse into the violent process of making rocky planets like ours.
Rocky planets begin life as dusty material circling around young stars. The material clumps together to form asteroids that ram into each other. Although the asteroids often are destroyed, some grow over time and transform into proto-planets. After about 100 million years, the objects mature into full-grown, terrestrial planets. Our moon is thought to have formed from a giant impact between proto-Earth and a Mars-size object.
In the new study, Spitzer set its heat-seeking infrared eyes on the dusty star NGC 2547-ID8, which is about 35 million years old and lies 1,200 light-years away in the Vela constellation. Previous observations had already recorded variations in the amount of dust around the star, hinting at possible ongoing asteroid collisions. In hope of witnessing an even larger impact, which is a key step in the birth of a terrestrial planet, the astronomers turned to Spitzer to observe the star regularly. Beginning in May 2012, the telescope began watching the star, sometimes daily.
A dramatic change in the star came during a time when Spitzer had to point away from NGC 2547-ID8 because our sun was in the way. When Spitzer started observing the star again five months later, the team was shocked by the data they received.
"We not only witnessed what appears to be the wreckage of a huge smashup, but have been able to track how it is changing -- the signal is fading as the cloud destroys itself by grinding its grains down so they escape from the star," said Kate Su of the University of Arizona and co-author on the study. "Spitzer is the best telescope for monitoring stars regularly and precisely for small changes in infrared light over months and even years."
A very thick cloud of dusty debris now orbits the star in the zone where rocky planets form. As the scientists observe the star system, the infrared signal from this cloud varies based on what is visible from Earth. For example, when the elongated cloud is facing us, more of its surface area is exposed and the signal is greater. When the head or the tail of the cloud is in view, less infrared light is observed. By studying the infrared oscillations, the team is gathering first-of-its-kind data on the detailed process and outcome of collisions that create rocky planets like Earth.
"We are watching rocky planet formation happen right in front of us," said George Rieke, a University of Arizona co-author of the new study. "This is a unique chance to study this process in near real-time."
The team is continuing to keep an eye on the star with Spitzer. They will see how long the elevated dust levels persist, which will help them calculate how often such events happen around this and other stars, and they might see another smashup while Spitzer looks on.
The results of this study are posted online Thursday in the journal Science.
NASA's Jet Propulsion Laboratory (JPL) in Pasadena, California, manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate in Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Spacecraft operations are based at Lockheed Martin Space Systems Company in Littleton, Colorado. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA.

Flying Through an Aurora
European Space Agency astronaut Alexander Gerst posted this photograph taken from the International Space Station to social media on Aug. 29, 2014, writing, "words can't describe how it feels flying through an #aurora. I wouldn't even know where to begin…."
Crewmembers on the space station photograph the Earth from their unique point of view located 200 miles above the surface. Photographs record how the planet is changing over time, from human-caused changes like urban growth and reservoir construction, to natural dynamic events such as hurricanes, floods and volcanic eruptions. Crewmembers have been photographing Earth from space since the early Mercury missions beginning in 1961. The continuous images taken from the space station ensure this record remains unbroken.
On Tuesday, Sept. 9 aboard the space station, cosmonaut Max Suraev of Roscosmos takes the helm when Expedition 40 Commander Steve Swanson hands over control during a Change of Command Ceremony at 5:15 p.m. EDT. Suraev will lead Expedition 41 and stay in orbit until November with Gerst and NASA astronaut Reid Wiseman. Soyuz Commander Alexander Skvortsov, Swanson and Flight Engineer Oleg Artemyev will complete their mission Wednesday, Sept. 10 at 7:01 p.m. when they undock in their Soyuz TMA-12M spacecraft from the Poisk docking compartment for a parachute-assisted landing on the steppe of Kazakhstan a little less than 3.5 hours later.
Image Credit: NASA/ESA/Alexander Gerst

Milky Way Viewed From the International Space Station
NASA astronaut Reid Wiseman captured this image from the International Space Station and posted it to social media on Sept. 28, 2014, writing, "The Milky Way steals the show from Sahara sands that make the Earth glow orange."
Aboard the space station, the six-person Expedition 41 crew is currently preparing for two spacewalks set for Oct. 7 and 15. During the first six-and-a-half-hour spacewalk, slated to begin on Oct. 7 around 8:10 a.m. EDT, Wiseman and European Space Agency astronaut Alexander Gerst will transfer a previously uninstalled pump module from its temporary stowage location to the External Stowage Platform-2. The two spacewalkers also will install the Mobile Transporter Relay Assembly that adds the capability to provide “keep-alive” power to the system that moves the station’s robotic arm between worksites. NASA astronaut Barry Wilmore will join Wiseman for the second Expedition 41 spacewalk on Oct. 15.
Image Credit: NASA/Reid Wiseman

The Odd Trio
The Cassini spacecraft captures a rare family photo of three of Saturn's moons that couldn't be more different from each other! As the largest of the three, Tethys (image center) is round and has a variety of terrains across its surface. Meanwhile, Hyperion (to the upper-left of Tethys) is the "wild one" with a chaotic spin and Prometheus (lower-left) is a tiny moon that busies itself sculpting the F ring.
To learn more about the surface of Tethys (660 miles, or 1,062 kilometers across), see PIA17164. More on the chaotic spin of Hyperion (168 miles, or 270 kilometers across) can be found at PIA07683. And discover more about the role of Prometheus (53 miles, or 86 kilometers across) in shaping the F ring in PIA12786.
This view looks toward the sunlit side of the rings from about 1 degree above the ringplane. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on July 14, 2014.
The view was acquired at a distance of approximately 1.2 million miles (1.9 million kilometers) from Tethys and at a Sun-Tethys-spacecraft, or phase, angle of 22 degrees. Image scale is 7 miles (11 kilometers) per pixel.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.
For more information about the Cassini-Huygens mission visit http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org .
Credit: NASA/JPL-Caltech/Space Science Institute

Wikipedia a écrit:Une supernova est l'ensemble des phénomènes conséquents à l'explosion d'une étoile, qui s'accompagne d'une augmentation brève mais fantastiquement grande de sa luminosité. Vue depuis la Terre, une supernova apparaît donc souvent comme une étoile nouvelle¹, alors qu'elle correspond en réalité à la disparition d'une étoile.

Unprecedented X-ray View of Supernova Remains
The destructive results of a powerful supernova explosion reveal themselves in a delicate tapestry of X-ray light, as seen in this image from NASA’s Chandra X-Ray Observatory and the European Space Agency's XMM-Newton.
The image shows the remains of a supernova that would have been witnessed on Earth about 3,700 years ago. The remnant is called Puppis A, and is around 7,000 light years away and about 10 light years across. This image provides the most complete and detailed X-ray view of Puppis A ever obtained, made by combining a mosaic of different Chandra and XMM-Newton observations. Low-energy X-rays are shown in red, medium-energy X-rays are in green and high energy X-rays are colored blue.
These observations act as a probe of the gas surrounding Puppis A, known as the interstellar medium. The complex appearance of the remnant shows that Puppis A is expanding into an interstellar medium that probably has a knotty structure.
Supernova explosions forge the heavy elements that can provide the raw material from which future generations of stars and planets will form. Studying how supernova remnants expand into the galaxy and interact with other material provides critical clues into our own origins.
A paper describing these results was published in the July 2013 issue of Astronomy and Astrophysics and is available online. The first author is Gloria Dubner from the Instituto de Astronomía y Física del Espacio in Buenos Aires in Argentina.
Image credit: NASA/CXC/IAFE/G.Dubner et al & ESA/XMM-Newton

NASA's Mars Curiosity rover has reached the Red Planet's Mount Sharp, a Mount-Rainier-size mountain at the center of the vast Gale Crater and the rover mission's long-term prime destination.
"Curiosity now will begin a new chapter from an already outstanding introduction to the world," said Jim Green, director of NASA's Planetary Science Division at NASA Headquarters in Washington. "After a historic and innovative landing along with its successful science discoveries, the scientific sequel is upon us."
Curiosity’s trek up the mountain will begin with an examination of the mountain's lower slopes. The rover is starting this process at an entry point near an outcrop called Pahrump Hills, rather than continuing on to the previously-planned, further entry point known as Murray Buttes. Both entry points lay along a boundary where the southern base layer of the mountain meets crater-floor deposits washed down from the crater’s northern rim.
"It has been a long but historic journey to this Martian mountain,” said Curiosity Project Scientist John Grotzinger of the California Institute of Technology in Pasadena. “The nature of the terrain at Pahrump Hills and just beyond it is a better place than Murray Buttes to learn about the significance of this contact. The exposures at the contact are better due to greater topographic relief."
After 2 years and nearly 9 kilometers of driving, NASA’s Mars Curiosity has arrived at the base of Mount Sharp.
The decision to head uphill sooner, instead of continuing to Murray Buttes, also draws from improved understanding of the region’s geography provided by the rover’s examinations of several outcrops during the past year. Curiosity currently is positioned at the base of the mountain along a pale, distinctive geological feature called the Murray Formation. Compared to neighboring

NASA Spacecraft Provides New Information About Sun’s Atmosphere
NASA's Interface Region Imaging Spectrograph (IRIS) has provided scientists with five new findings into how the sun’s atmosphere, or corona, is heated far hotter than its surface, what causes the sun’s constant outflow of particles called the solar wind, and what mechanisms accelerate particles that power solar flares.
The new information will help researchers better understand how our nearest star transfers energy through its atmosphere and track the dynamic solar activity that can impact technological infrastructure in space and on Earth. Details of the findings appear in the current edition of Science.
 "These findings reveal a region of the sun more complicated than previously thought," said Jeff Newmark, interim director for the Heliophysics Division at NASA Headquarters in Washington. "Combining IRIS data with observations from other Heliophysics missions is enabling breakthroughs in our understanding of the sun and its interactions with the solar system."
The first result identified heat pockets of 200,000 degrees Fahrenheit, lower in the solar atmosphere than ever observed by previous spacecraft. Scientists refer to the pockets as solar heat bombs because of the amount of energy they release in such a short time. Identifying such sources of unexpected heat can offer deeper understanding of the heating mechanisms throughout the solar atmosphere.
For its second finding, IRIS observed numerous, small, low lying loops of solar material in the interface region for the first time. The unprecedented resolution provided by IRIS will enable scientists to better understand how the solar atmosphere is energized.
A surprise to researchers was the third finding of IRIS observations showing structures resembling mini-tornadoes occurring in solar active regions for the first time. These tornadoes move at speeds as fast as 12 miles per second and are scattered throughout the chromosphere, or the layer of the sun in the interface region just above the surface.  These tornados provide a mechanism for transferring energy to power the million-degree temperatures in the corona.
Another finding uncovers evidence of high-speed jets at the root of the solar wind.  The jets are fountains of plasma that shoot out of coronal holes, areas of less dense material in the solar atmosphere and are typically thought to be a source of the solar wind.
The final result highlights the effects of nanoflares throughout the corona. Large solar flares are initiated by a mechanism called magnetic reconnection, whereby magnetic field lines cross and explosively realign. These often send particles out into space at nearly the speed of light. Nanoflares are smaller versions that have long been thought to drive coronal heating. IRIS observations show high energy particles generated by individual nanoflare events impacting the chromosphere for the first time.      
"This research really delivers on the promise of IRIS, which has been looking at a region of the sun with a level of detail that has never been done before," said De Pontieu, IRIS science lead at Lockheed Martin in Palo Alto, California. "The results focus on a lot of things that have been puzzling for a long time and they also offer some complete surprises."
IRIS is a Small Explorer mission managed by NASA’s Goddard Space Flight Center, in Greenbelt, Maryland for the agency’s Science Mission Directorate at NASA Headquarters. NASA's Ames Research Center in Moffett Field, California, provides mission operations and ground data systems. The Norwegian Space Centre is providing regular downlinks of science data. Lockheed Martin designed the IRIS observatory and manages the mission for NASA. The Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, built the telescope. Montana State University in Bozeman designed the spectrograph. Other contributors for this mission include the University of Oslo and Stanford University in Stanford, California.
For more information about IRIS, visit:

http://www.nasa.gov/iris

NASA’s Hubble Finds Extremely Distant Galaxy through Cosmic Magnifying Glass
Peering through a giant cosmic magnifying glass, NASA’s Hubble Space Telescope has spotted a tiny, faint galaxy -- one of the farthest galaxies ever seen. The diminutive object is estimated to be more than 13 billion light-years away.
This galaxy offers a peek back to the very early formative years of the universe and may just be the tip of the iceberg.
“This galaxy is an example of what is suspected to be an abundant, underlying population of extremely small, faint objects that existed about 500 million years after the big bang, the beginning of the universe,” explained study leader Adi Zitrin of the California Institute of Technology in Pasadena, California. “The discovery is telling us galaxies as faint as this one exist, and we should continue looking for them and even fainter objects, so that we can understand how galaxies and the universe have evolved over time.”
The galaxy was detected by the Frontier Fields program, an ambitious three-year effort that teams Hubble with NASA’s other great observatories -- the Spitzer Space Telescope and Chandra X-ray Observatory -- to probe the early universe by studying large galaxy clusters. These clusters are so massive their gravity deflects light passing through them, magnifying, brightening, and distorting background objects in a phenomenon called gravitational lensing. These powerful lenses allow astronomers to find many dim, distant structures that otherwise might be too faint to see.
The discovery was made using the lensing power of the mammoth galaxy cluster Abell 2744, nicknamed Pandora’s Cluster, which produced three magnified images of the same, faint galaxy. Each magnified image makes the galaxy appear 10 times larger and brighter than it would look without the zooming qualities of the cluster.
The galaxy measures merely 850 light-years across -- 500 times smaller than our Milky Way galaxy-- and is estimated to have a mass of only 40 million suns. The Milky Way, in comparison, has a stellar mass of a few hundred billion suns. And the galaxy forms about one star every three years, whereas the Milky Way galaxy forms roughly one star per year. However, given its small size and low mass, Zitrin said the tiny galaxy actually is rapidly evolving and efficiently forming stars.
The astronomers believe galaxies such as this one are probably small clumps of matter that started to form stars and shine, but do not yet have a defined structure. It is possible Hubble is only detecting one bright clump magnified due to the lensing. This would explain why the object is smaller than typical field galaxies of that time.
Zitrin’s team spotted the galaxy’s gravitationally multiplied images using near-infrared and visible-light photos of the galaxy cluster taken by Hubble’s Wide Field Camera 3 and Advanced Camera for Surveys. But they needed to measure how far away it was from Earth.
Usually, astronomers can determine an object’s distance based on how far its light has been stretched as the universe slowly expands. Astronomers can precisely measure this effect through spectroscopy, which characterizes an object’s light. But the gravitationally-lensed galaxy and other objects found at this early time period are too far away and too dim for spectroscopy, so astronomers use an object’s color to estimate its distance. The universe’s expansion reddens an object’s color in predictable ways, which scientists can measure.
Zitrin’s team performed the color-analysis technique and took advantage of the multiple images produced by the gravitational lens to independently confirm the group’s distance estimate. The astronomers measured the angular separation between the three magnified images of the galaxy in the Hubble photos. The greater the angular separation due to lensing, the farther away the object is from Earth.
To test this concept, the astronomers compared the three magnified images with the locations of several other closer, multiply-imaged background objects captured in Hubble images of Pandora’s cluster. The angular distance between the magnified images of the closer galaxies was smaller.
“These measurements imply that, given the large angular separation between the three images of our background galaxy, the object must lie very far away,” Zitrin explained. “It also matches the distance estimate we calculated, based on the color-analysis technique. So we are about 95 percent confident this object is at a remote distance, at redshift 10, a measure of the stretching of space since the big bang. The lensing takes away any doubt that this might be a heavily reddened, nearby object masquerading as a far more distant object.”
Astronomers have long debated whether such early galaxies could have provided enough radiation to warm the hydrogen that cooled soon after the big bang. This process, called reionization, is thought to have occurred 200 million to 1 billion years after the birth of the universe. Reionization made the universe transparent to light, allowing astronomers to look far back into time without running into a “fog” of cold hydrogen.
The team’s results appeared in the September online edition of The Astrophysical Journal Letters.
The Hubble Space Telescope is a project of international cooperation between NASA and the European Space Agency. NASA's Goddard Space Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore conducts Hubble science operations. STScI is operated for NASA by the Association of Universities for Research in Astronomy, Inc., in Washington.
For images and more information about Hubble, visit:

http://www.nasa.gov/hubble

Mimas (S I Mimas) est un satellite naturel de Saturne, découvert en 1789 par William Herschel. Il tire son nom de Mimas, un Géant de la mythologie grecque.
Mimas est le satellite sphéroïde, parmi six autres, le plus proche de Saturne mais aussi le plus petit. Son diamètre varie de 382 à 418 km. Les 7 autres petits satellites connus situés entre son orbite et la surface de la planète géante ont tous un diamètre inférieur à 200 km, autrement dit d'une masse trop faible pour assurer une forme sphérique de cohésion. La faible densité de Mimas (1,17) laisse à penser qu'il est principalement constitué de glace d'eau avec une petite proportion de roches.
Sa masse fut calculée par Hermann Struve grâce à l'effet de résonance avec Téthys, qui induit des oscillations dans les longitudes de ces deux satellites. Le rapport de celles-ci est proportionnel au rapport des masses.

Crescent Mimas
A thin sliver of Mimas is illuminated, the long shadows showing off its many craters, indicators of the moon's violent history.
The most famous evidence of a collision on Mimas (246 miles, or 396 kilometers across) is the crater Herschel that gives Mimas its Death Star-like appearance. See PIA12568 for more on Herschel.
This view looks toward the anti-Saturn hemisphere of Mimas. North on Mimas is up and rotated 40 degrees to the right. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on May 20, 2013.
The view was acquired at a distance of approximately 100,000 miles (200,000 kilometers) from Mimas and at a Sun-Mimas-spacecraft, or phase, angle of 130 degrees. Image scale is 4,000 feet (1 kilometer) per pixel.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.
For more information about the Cassini-Huygens mission visit http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org .
Credit: NASA/JPL-Caltech/Space Science Institute

Rosetta Comet Fires Its Jets
The four images that make up this montage of comet 67P/Churyumov–Gerasimenko were taken on Sept. 26, 2014 by the European Space Agency’s Rosetta spacecraft. At the time, Rosetta was about 16 miles (26 kilometers), from the center of the comet.
In the montage, a region of jet activity can be seen at the neck of the comet. These jets, originating from several discrete locations, are a product of ices sublimating and gases escaping from inside the nucleus.  
The overlapping and slightly dissimilar angles of the four images that compose the montage are a result of the combined effect of the comet rotating between the first and last images taken in the sequence (about 10 degrees over 20 minutes), and the spacecraft movement during that same time.
Launched in March 2004, Rosetta was reactivated in January 2014 after a record 957 days in hibernation. Composed of an orbiter and lander, Rosetta's objectives since arriving at comet 67P/Churyumov-Gerasimenko earlier this month are to study the celestial object up close in unprecedented detail, prepare for landing a probe on the comet's nucleus in November, and after the landing track the comet's changes through 2015, as it sweeps past the sun.
Comets are time capsules containing primitive material left over from the epoch when the sun and its planets formed. Rosetta's lander will obtain the first images taken from a comet's surface and will provide comprehensive analysis of the comet's possible primordial composition by drilling into the surface. Rosetta also will be the first spacecraft to witness at close proximity how a comet changes as it is subjected to the increasing intensity of the sun's radiation. Observations will help scientists learn more about the origin and evolution of our solar system and the role comets may have played in seeding Earth with water, and perhaps even life.
Rosetta is an ESA mission with contributions from its member states and NASA. Rosetta's Philae lander is provided by a consortium led by the German Aerospace Center, Cologne; Max Planck Institute for Solar System Research, Gottingen; National Center of Space Studies of France (CNES), Paris; and the Italian Space Agency, Rome. NASA's Jet Propulsion Laboratory in Pasadena, California, a division of the California Institute of Technology, manages the U.S. participation in the Rosetta mission for NASA's Science Mission Directorate in Washington.
For more information on the U.S. instruments aboard Rosetta, visit:
http://rosetta.jpl.nasa.gov
More information about Rosetta is available at:
http://www.esa.int/rosetta
Image Credit: ESA/Rosetta/NAVCAM

Like a drop of dew hanging on a leaf, Tethys appears to be stuck to the A and F rings from this perspective.
Tethys (660 miles, or 1,062 kilometers across), like the ring particles, is composed primarily of ice. The gap in the A ring through which Tethys is visible is the Keeler gap, which is kept clear by the small moon Daphnis (not visible here).
This view looks toward the Saturn-facing hemisphere of Tethys. North on Tethys is up and rotated 43 degrees to the right. The image was taken in visible light with the Cassini spacecraft narrow-angle camera on July 14, 2014.
The view was acquired at a distance of approximately 1.1 million miles (1.8 million kilometers) from Tethys and at a Sun-Tethys-spacecraft, or phase, angle of 22 degrees. Image scale is 7 miles (11 kilometers) per pixel.
The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. The Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington, D.C. The Cassini orbiter and its two onboard cameras were designed, developed and assembled at JPL. The imaging operations center is based at the Space Science Institute in Boulder, Colo.
For more information about the Cassini-Huygens mission visit http://www.nasa.gov/cassini and http://saturn.jpl.nasa.gov . The Cassini imaging team homepage is at http://ciclops.org .
Credit: NASA/JPL-Caltech/Space Science Institute

NASA Mission Finds Widespread Evidence of Young Lunar Volcanism
The feature called Maskelyne is one of many newly discovered young volcanic deposits on the Moon. Called irregular mare patches, these areas are thought to be remnants of small basaltic eruptions that occurred much later than the commonly accepted end of lunar volcanism, 1 to 1.5 billion years ago.
Image Credit: 
NASA/GSFC/Arizona State University

ASA’s Lunar Reconnaissance Orbiter (LRO) has provided researchers strong evidence the moon’s volcanic activity slowed gradually instead of stopping abruptly a billion years ago.
Scores of distinctive rock deposits observed by LRO are estimated to be less than 100 million years old. This time period corresponds to Earth’s Cretaceous period, the heyday of dinosaurs. Some areas may be less than 50 million years old. Details of the study are published online in Sunday’s edition of Nature Geoscience.
“This finding is the kind of science that is literally going to make geologists rewrite the textbooks about the moon,” said John Keller, LRO project scientist at NASA’s Goddard Space Flight Center in Greenbelt, Maryland.
The deposits are scattered across the moon’s dark volcanic plains and are characterized by a mixture of smooth, rounded, shallow mounds next to patches of rough, blocky terrain. Because of this combination of textures, the researchers refer to these unusual areas as irregular mare patches.
The features are too small to be seen from Earth, averaging less than a third of a mile (500 meters) across in their largest dimension. One of the largest, a well-studied area called Ina, was imaged from lunar orbit by Apollo 15 astronauts.
Ina appeared to be a one-of-a-kind feature until researchers from Arizona State University in Tempe and Westfälische Wilhelms-Universität Münster in Germany spotted many similar regions in high-resolution images taken by the two Narrow Angle Cameras that are part of the Lunar Reconnaissance Orbiter Camera, or LROC. The team identified a total of 70 irregular mare patches on the near side of the moon.
The large number of these features and their wide distribution strongly suggest that late-stage volcanic activity was not an anomaly but an important part of the moon's geologic history.
The numbers and sizes of the craters within these areas indicate the deposits are relatively recent. Based on a technique that links such crater measurements to the ages of Apollo and Luna samples, three of the irregular mare patches are thought to be less than 100 million years old, and perhaps less than 50 million years old in the case of Ina. The steep slopes leading down from the smooth rock layers to the rough terrain are consistent with the young age estimates.
In contrast, the volcanic plains surrounding these distinctive regions are attributed to volcanic activity that started about 3 1/2 billion years ago and ended roughly 1 billion years ago. At that point, all volcanic activity on the moon was thought to cease.
Several earlier studies suggested that Ina was quite young and might have formed due to localized volcanic activity. However, in the absence of other similar features, Ina was not considered an indication of widespread volcanism.
The findings have major implications for how warm the moon’s interior is thought to be.
“The existence and age of the irregular mare patches tell us that the lunar mantle had to remain hot enough to provide magma for the small-volume eruptions that created these unusual young features,” said Sarah Braden, a recent Arizona State University graduate and the lead author of the study.
The new information is hard to reconcile with what currently is thought about the temperature of the interior of the moon.
“These young volcanic features are prime targets for future exploration, both robotic and human,” said Mark Robinson, LROC principal investigator at Arizona State University.
LRO is managed by Goddard for NASA’s Science Mission Directorate at NASA Headquarters in Washington. LROC, a system of three cameras, was designed and built by Malin Space Science Systems and is operated by Arizona State University.
To access the complete collection of LROC images, visit

http://lroc.sese.asu.edu/

NASA’s Chandra X-ray Observatory Finds Planet That Makes Star Act Deceptively Old
A new study from NASA’s Chandra X-ray Observatory shows that a giant exoplanet, WASP-18b, is making the star that it orbits very closely act much older than it actually is. This artist’s illustration depicts WASP-18b and its star, which are about 330 light years away
Image Credit:  NASA/CXC/M. Weiss 

A planet may be causing the star it orbits to act much older than it actually is, according to new data from NASA’s Chandra X-ray Observatory. This discovery shows how a massive planet can affect the behavior of its parent star.
The star, WASP-18, and its planet, WASP-18b, are located about 330 light-years from Earth. WASP-18b has a mass about 10 times that of Jupiter and completes one orbit around its star in less than 23 hours, placing WASP-18b in the “hot Jupiter” category of exoplanets, or planets outside our solar system.
WASP-18b is the first known example of an orbiting planet that has apparently caused its star, which is roughly the mass of our sun, to display traits of an older star.
“WASP-18b is an extreme exoplanet," said Ignazio Pillitteri of the Istituto Nazionale di Astrofisica (INAF)-Osservatorio Astronomico di Palermo in Italy, who led the study. "It is one of the most massive hot Jupiters known and one of the closest to its host star, and these characteristics lead to unexpected behavior. This planet is causing its host star to act old before its time.”
Pillitteri’s team determined WASP-18 is between 500 million and 2 billion years old, based on theoretical models and other data. While this may sound old, it is considered young by astronomical standards. By comparison, our sun is about 5 billion years old and thought to be about halfway through its lifetime.
Younger stars tend to be more active, exhibiting stronger magnetic fields, larger flares, and more intense X-ray emission than their older counterparts. Magnetic activity, flaring, and X-ray emission are linked to the star’s rotation, which generally declines with age. However, when astronomers took a long look with Chandra at WASP-18 they didn’t detect any X-rays. Using established relations between the magnetic activity and X-ray emission of stars, as well as its actual age, researchers determined WASP-18 is about 100 times less active than it should be.
“We think the planet is aging the star by wreaking havoc on its innards,” said co-author Scott Wolk of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts.
The researchers argue that tidal forces created by the gravitational pull of the massive planet – similar to those the moon has on Earth’s tides, but on a much larger scale – may have disrupted the magnetic field of the star.
The strength of the magnetic field depends on the amount of convection in the star, or how intensely hot gas stirs the interior of the star.
“The planet’s gravity may cause motions of gas in the interior of the star that weaken the convection,” said co-author Salvatore Sciortino also of INAF-Osservatorio Astronomico di Palermo in Italy. “This has a domino effect that results in the magnetic field becoming weaker and the star to age prematurely.”
WASP-18 is particularly susceptible to this effect because its convection zone is narrower than most stars. This makes it more vulnerable to the impact of tidal forces that tug at it.
The effect of tidal forces from the planet may also explain an unusually high amount of lithium found in earlier optical studies of WASP-18. Lithium is usually abundant in younger stars, but over time convection carries lithium to the hot inner regions of a star, where it is destroyed by nuclear reactions. If there is less convection, the lithium does not circulate into the interior of the star as much, allowing more lithium to survive.
These results were published in the July issue of Astronomy and Astrophysics and are available online.
NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.
An interactive image, podcast, and video on these findings are available at:

http://chandra.si.edu

Hinode Captures Images of Partial Solar Eclipse
A partial solar eclipse was visible from much of North America before sundown on Thursday, Oct.23. A partial eclipse occurs when the moon blocks a portion of the sun from view.
The Hinode spacecraft captured images of yesterday’s eclipse as it passed over North America using its X-ray Telescope.  During the eclipse, the new moon eased across the sun from right to left with the Sun shining brilliantly in the background.  And as a stroke of good luck, this solar cycle’s largest active region, which has been the source of several large flares over the past week, was centered on the sun’s disk as the moon transited!
Hinode is in the eighth year of its mission to observe the sun. Previously, Hinode has observed numerous eclipses due to its high-altitude, sun-synchronous orbit.  As viewed from Hinode’s vantage point in space, this eclipse was annular instead of partial, which means that the entire moon moved in front of the sun but did not cover it completely.  In this situation, a ring of the sun encircles the dark disk of the moon.
Led by the Japan Aerospace Exploration Agency (JAXA), the Hinode mission is a collaboration between the space agencies of Japan, the United States, the United Kingdom and Europe. NASA helped in the development, funding and assembly of the spacecraft's three science instruments.
Hinode is part of the Solar Terrestrial Probes (STP) Program within the Heliophysics Division of NASA's Science Mission Directorate in Washington. NASA's Marshall Space Flight Center in Huntsville, Ala., manages the Hinode science operations. The Smithsonian Astrophysical Observatory is the lead U.S. investigator for the X-ray telescope.
Image Credit: NASA/JAXA/SAO

Chandra observations of the Perseus and Virgo galaxy clusters suggest turbulence may be preventing hot gas there from cooling, addressing a long-standing question of galaxy clusters do not form large numbers of stars.
Image Credit: 
NASA/CXC/Stanford/I. Zhuravleva et al

NASA’S Chandra Observatory Identifies Impact of Cosmic Chaos on Star Birth
The same phenomenon that causes a bumpy airplane ride, turbulence, may be the solution to a long-standing mystery about stars’ birth, or the absence of it, according to a new study using data from NASA’s Chandra X-ray Observatory.
Galaxy clusters are the largest objects in the universe, held together by gravity.  These behemoths contain hundreds or thousands of individual galaxies that are immersed in gas with temperatures of millions of degrees.
This hot gas, which is the heftiest component of the galaxy clusters aside from unseen dark matter, glows brightly in X-ray light detected by Chandra. Over time, the gas in the centers of these clusters should cool enough that stars form at prodigious rates. However, this is not what astronomers have observed in many galaxy clusters.
“We knew that somehow the gas in clusters is being heated to prevent it cooling and forming stars. The question was exactly how,” said Irina Zhuravleva of Stanford University in Palo Alto, California, who led the study that appears in the latest online issue of the journal Nature. “We think we may have found evidence that the heat is channeled from turbulent motions, which we identify from signatures recorded in X-ray images.”
Prior studies show supermassive black holes, centered in large galaxies in the middle of galaxy clusters, pump vast quantities of energy around them in powerful jets of energetic particles that create cavities in the hot gas. Chandra, and other X-ray telescopes, have detected these giant cavities before.
The latest research by Zhuravleva and her colleagues provides new insight into how energy can be transferred from these cavities to the surrounding gas. The interaction of the cavities with the gas may be generating turbulence, or chaotic motion, which then disperses to keep the gas hot for billions of years.
“Any gas motions from the turbulence will eventually decay, releasing their energy to the gas,” said co-author Eugene Churazov of the Max Planck Institute for Astrophysics in Munich, Germany. “But the gas won’t cool if turbulence is strong enough and generated often enough.”
The evidence for turbulence comes from Chandra data on two enormous galaxy clusters named Perseus and Virgo. By analyzing extended observation data of each cluster, the team was able to measure fluctuations in the density of the gas. This information allowed them to estimate the amount of turbulence in the gas.
“Our work gives us an estimate of how much turbulence is generated in these clusters,” said Alexander Schekochihin of the University of Oxford in the United Kingdom. “From what we’ve determined so far, there’s enough turbulence to balance the cooling of the gas.
These results support the “feedback” model involving supermassive black holes in the centers of galaxy clusters. Gas cools and falls toward the black hole at an accelerating rate, causing the black hole to increase the output of its jets, which produce cavities and drive the turbulence in the gas. This turbulence eventually dissipates and heats the gas.
While a merger between two galaxy clusters may also produce turbulence, the researchers think that outbursts from supermassive black holes are the main source of this cosmic commotion in the dense centers of many clusters.
NASA's Marshall Space Flight Center in Huntsville, Alabama, manages the Chandra program for NASA's Science Mission Directorate in Washington. The Smithsonian Astrophysical Observatory in Cambridge, Massachusetts, controls Chandra's science and flight operations.
An interactive image, podcast, and video about these findings are available at:

Here’s Looking at You: Spooky Shadow Gives Jupiter a Giant Eye
This trick that the planet is looking back at you is actually a Hubble treat: An eerie, close-up view of Jupiter, the biggest planet in our solar system. Hubble was monitoring changes in Jupiter’s immense Great Red Spot (GRS) storm on April 21, 2014, when the shadow of the Jovian moon, Ganymede, swept across the center of the storm. This gave the giant planet the uncanny appearance of having a pupil in the center of a 10,000 mile-diameter “eye.” For a moment, Jupiter “stared” back at Hubble like a one-eyed giant Cyclops

Sunrise From the International Space Station
NASA astronaut Reid Wiseman posted this image of a sunrise, captured from the International Space Station, to social media on Oct. 29, 2014. Wiseman wrote, "Not every day is easy. Yesterday was a tough one. #sunrise"
Wiseman was referring to the loss on Oct. 28 of the Orbital Sciences Corporation Antares rocket and Cygnus spacecraft, moments after launch at NASA's Wallops Flight Facility in Virginia. The Cygnus spacecraft was filled with about 5,000 pounds of supplies slated for the International Space Station, including science experiments, experiment hardware, spare parts, and crew provisions.
The station crew is in no danger of running out of food or other critical supplies.
Image Credit: NASA/Reid Wiseman

NASA's Solar Dynamics Observatory Captures Intense Space Weather
An active region on the sun emitted a mid-level solar flare, peaking at 4:47 a.m. EST on Nov. 5, 2014. This is the second mid-level flare from the same active region, labeled AR 12205, which rotated over the left limb of the sun on Nov. 3. The image was captured by NASA's Solar Dynamics Observatory (SDO) in extreme ultraviolet light that was colorized in red and gold.
Solar flares are powerful bursts of radiation. Harmful radiation from a flare cannot pass through Earth's atmosphere to physically affect humans on the ground, however -- when intense enough -- they can disturb the atmosphere in the layer where GPS and communications signals travel.
This flare is classified as an M7.9-class flare. M-class flares are a tenth the size of the most intense flares, the X-class flares. The number provides more information about its strength. An M2 is twice as intense as an M1, an M3 is three times as intense, etc.

• 9h30 : séparation et début de la descente de Philae ; confirmation à 10h03
  
• 9h45 : ouverture du train d'atterrissage de Philae
  
• 15h30 : début de la retransmission web en vidéos multi-flux
  
• 15h54 : début des prises de vue du site d'atterrissage Agilkia par la caméra ROLIS
  
• 16h34 : contact avec la surface de la comète 67P/Churyumov-Gerasimenko
  
• 17h (+ ou - 15 min) : confirmation de l'atterrissage par le centre de contrôle de Philae
  
• 19h : réception du panorama du paysage autour de Philae