Sunday, July 27, 2014

Where are the Best Windows Into Europa's Interior?

Where are the Best Windows Into Europa's Interior?:

Energy From Above Affecting Surface of Europa
This graphic of Jupiter's moon Europa maps a relationship between the amount of energy deposited onto the moon from charged-particle bombardment and the chemical contents of ice deposits on the surface in five areas of the moon (labeled A through E). Credit: NASA/JPL-Caltech/Univ. of Ariz./JHUAPL/Univ. of Colo.
› Full image and caption

April 12, 2013

The surface of Jupiter's moon Europa exposes material churned up from inside the moon and also material resulting from matter and energy coming from above. If you want to learn about the deep saltwater ocean beneath this unusual world's icy shell -- as many people do who are interested in possible extraterrestrial life -- you might target your investigation of the surface somewhere that has more of the up-from-below stuff and less of the down-from-above stuff.


New analysis of observations made more than a decade ago by NASA's Galileo mission to Jupiter helps identify those places.


"We have found the regions where charged electrons and ions striking the surface would have done the most, and the least, chemical processing of materials emplaced at the surface from the interior ocean," said J. Brad Dalton of NASA's Jet Propulsion Laboratory, Pasadena, Calif., lead author of the report published recently in the journal Planetary and Space Science. "That tells us where to look for materials representing the most pristine ocean composition, which would be the best places to target with a lander or study with an orbiter."


Europa is about the size of Earth's moon and, like our moon, keeps the same side toward the planet it orbits. Picture a car driving in circles around a mountain with its left-side windows always facing the mountain.


Europa's orbit around Jupiter is filled with charged, energetic particles tied to Jupiter's powerful magnetic field. Besides electrons, these particles include ions of sulfur and oxygen originating from volcanic eruptions on Io, a neighboring moon.


The magnetic field carrying these energetic particles sweeps around Jupiter faster than Europa orbits Jupiter, in the same direction: about 10 hours per circuit for the magnetic field versus about 3.6 days for Europa's orbit. So, instead of our mountain-circling car getting bugs on the front windshield, the bugs are plastered on the back of the car by a "wind" from behind going nearly nine times faster than the car. Europa has a "leading hemisphere" in front and a "trailing hemisphere" in back.


Earlier studies had found more sulfuric acid being produced toward the center of the trailing hemisphere than elsewhere on Europa's surface, interpreted as resulting from chemistry driven by sulfur ions bombarding the icy surface.


Dalton and his co-authors at JPL and at Johns Hopkins University Applied Physics Laboratory, Laurel, Md., examined data from observations by Galileo's near infrared mapping spectrometer of five widely distributed areas of Europa's surface. The spectra of reflected light from frozen material on the surface enabled them to distinguish between relatively pristine water and sulfate hydrates. These included magnesium and sodium sulfate salt hydrates, and hydrated sulfuric acid. They compared the distributions of these substances with models of how the influxes of energetic electrons and of sulfur and oxygen ions are distributed around the surface of Europa.


The concentration of frozen sulfuric acid on the surface varies greatly, they found. It ranges from undetectable levels near the center of the leading hemisphere, to more than half of the surface materials near the center of the heavily bombarded trailing hemisphere. The concentration was closely related to the amount of electrons and sulfur ions striking the surface.


"The close correlation of electron and ion fluxes with the sulfuric acid hydrate concentrations indicates that the surface chemistry is affected by these charged particles," says Dalton. "If you are interested in the composition and habitability of the interior ocean, the best places to study would be the parts of the leading hemisphere we have identified as receiving the fewest electrons and having the lowest sulfuric acid concentrations."


Surface deposits in these areas are most likely to preserve the original chemical compounds that erupted from the interior. Dalton suggests that any future spacecraft missions to Europa should target these deposits for study from orbit, or even attempt to land there.


Dalton said, "The darkest material, on the trailing hemisphere, is probably the result of externally-driven chemical processing, with little of the original oceanic material intact. While investigating the products of surface chemistry driven by charged particles is still interesting from a scientific standpoint, there is a strong push within the community to characterize the contents of the ocean and determine whether it could support life. These kinds of places just might be the windows that allow us to do that."


The study was funded by NASA's Outer Planets Research Program. NASA's Galileo mission, launched in 1989, orbited Jupiter, investigating the planet and its diverse moons from 1995 to 2003. JPL, a division of the California Institute of Technology in Pasadena, managed Galileo for NASA's Science Mission Directorate, Washington.

Guy Webster 818-354-6278

Jet Propulsion Laboratory, Pasadena, Calif.

guy.webster@jpl.nasa.gov


2013-134
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Comet to Make Close Flyby of Red Planet in October 2014

Comet to Make Close Flyby of Red Planet in October 2014:

This computer graphic depicts the orbit of comet 2013 A1 (Siding Spring) through the inner solar system.
This computer graphic depicts the orbit of comet 2013 A1 (Siding Spring) through the inner solar system.
Image credit: NASA/JPL-Caltech
› Larger image

March 05, 2013

Comet 2013 A1 (Siding Spring) will make a very close approach to Mars in October 2014.


The latest trajectory of comet 2013 A1 (Siding Spring) generated by the Near-Earth Object Program Office at NASA's Jet Propulsion Laboratory in Pasadena, Calif., indicates the comet will pass within 186,000 miles (300,000 kilometers) of Mars and there is a strong possibility that it might pass much closer. The NEO Program Office's current estimate based on observations through March 1, 2013, has it passing about 31,000 miles (50,000 kilometers) from the Red Planet's surface. That distance is about two-and-a-half times that of the orbit of outermost moon, Deimos.


Scientists generated the trajectory for comet Siding Spring based on the data obtained by observations since October 2012. Further refinement to its orbit is expected as more observational data is obtained. At present, Mars lies within the range of possible paths for the comet and the possibility of an impact cannot be excluded. However, since the impact probability is currently less than one in 600, future observations are expected to provide data that will completely rule out a Mars impact.


During the close Mars approach the comet will likely achieve a total visual magnitude of zero or brighter, as seen from Mars-based assets. From Earth, the comet is not expected to reach naked eye brightness, but it may become bright enough (about magnitude 8) that it could be viewed from the southern hemisphere in mid-September 2014, using binoculars, or small telescopes.


Scientists at the Near-Earth Object Program Office estimate that comet Siding Spring has been on a more than a million-year journey, arriving from our solar system's distant Oort cloud. The comet could be complete with the volatile gases that short period comets often lack due to their frequent returns to the sun's neighborhood.


Rob McNaught discovered comet 2013 A1 Siding Spring on Jan. 3, 2013, at Siding Spring Observatory in Australia. A study of germane archival observations has unearthed more images of the comet, extending the observation interval back to Oct. 4, 2012.


NASA detects, tracks and characterizes asteroids and comets passing close to Earth using both ground- and space-based telescopes. The Near-Earth Object Observations Program, commonly called "Spaceguard," discovers these objects, characterizes a subset of them, and plots their orbits to determine if any could be potentially hazardous to our planet.


JPL manages the Near-Earth Object Program Office for NASA's Science Mission Directorate in Washington. JPL is a division of the California Institute of Technology in Pasadena.


More information about asteroids and near-Earth objects is at: http://www.jpl.nasa.gov/asteroidwatch . More information about asteroid radar research is at: http://echo.jpl.nasa.gov/ . More information about the Deep Space Network is at: http://deepspace.jpl.nasa.gov/dsn .

DC Agle 818-393-9011

Jet Propulsion Laboratory, Pasadena, Calif.

agle@jpl.nasa.gov


Dwayne Brown 202-358-1726

NASA Headquarters, Washington

dwayne.c.brown@nasa.gov


2013-081
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How to Target an Asteroid

How to Target an Asteroid:

Tempel Alive with Light
This spectacular image of comet Tempel 1 was taken 67 seconds after it obliterated Deep Impact's impactor spacecraft. Image credit:
NASA/JPL-Caltech/UMD
› Full image and caption

April 16, 2013

Like many of his colleagues at NASA's Jet Propulsion Laboratory, Pasadena, Calif., Shyam Bhaskaran is working a lot with asteroids these days. And also like many of his colleagues, the deep space navigator devotes a great deal of time to crafting, and contemplating, computer-generated 3-D models of these intriguing nomads of the solar system.


But while many of his coworkers are calculating asteroids' past, present and future locations in the cosmos, zapping them with the world's most massive radar dishes, or considering how to rendezvous and perhaps even gently nudge an asteroid into lunar orbit, Bhaskaran thinks about how to collide with one.


"If you want to see below the surface of an asteroid, there's no better way than smacking it hard," said Bhaskaran. "But it's not that easy. Hitting an asteroid with a spacecraft traveling at hypervelocity is like shooting an arrow at a target on a speeding race car."


The term hypervelocity usually refers to something traveling at very high speed -- two miles per second (6,700 mph / 11,000 kilometers per hour) or above. Bhaskaran's hypothetical impacts tend to be well above.


"Most of the hypervelocity impact scenarios that I simulate have spacecraft/asteroid closure rates of around eight miles a second, 30,000 miles per hour [about 48,000 kilometers per hour]," said Bhaskaran.


In the majority of our solar system, where yield signs and "right of way" statutes have yet to find widespread support, hypervelocity impacts between objects happen all the time. But all that primordial violence usually goes unnoticed here on Earth, and almost never receives scientific scrutiny.


"High-speed impacts on asteroids can tell you so many things that we want to know about asteroids," said Steve Chesley, a near-Earth object scientist at JPL. "They can tell you about their composition and their structural integrity -- which is how they hold themselves together. These are things that are not only vital for scientific research on the origins of the solar system, but also for mission designers working on ways to potentially move asteroids, either for exploitation purposes or because they may be hazardous to Earth."


Hypervelocity impacts by spacecraft are not just a hypothetical exercise. Scientists have taken the opportunity to analyze data from used spacecraft and rocket stages that have impacted the moon and other celestial bodies since the Apollo program. On July 4, 2005, NASA's Deep Impact spacecraft successfully collided its dynamic impactor with comet 9P/Tempel 1 -- it was the first hypervelocity impact of a primitive solar system body.


Bhaskaran, who was a navigator on Deep Impact, would be the first to tell you that not all hypervelocity impacts are created equal. "Impacting an asteroid presents slightly different challenges than impacting a comet," said Bhaskaran. "Comets can have jets firing material into space, which can upset your imaging and guidance systems, while potential asteroid targets can be as small as 50 meters [164 feeet] and have their own mini-moons orbiting them. Since they're small and dim, they can be harder to spot."


Along with the size of the celestial body being targeted, Bhaskaran also has to take into account its orbit, targeting errors, how hard an impact the scientists want, and even the shape.


"Asteroids hardly ever resemble perfect spheroids," said Bhaskaran. "What you've got floating around out there are a bunch of massive objects that look like peanuts, potatoes, diamonds, boomerangs and even dog bones -- and if the spacecraft's guidance system can't figure out where it needs to go, you can hit the wrong part of the asteroid, or much worse, miss it entirely."


The guidance system Bhaskaran is referring to is called "AutoNav," which stands for Autonomous Navigation. To reach out and touch something that could be halfway across the solar system and traveling at hypervelocity requires a fast-thinking and fast-maneuvering spacecraft. It is a problem that even the speed of light cannot cure. "When it comes to these high-speed impact scenarios, the best info you get on where you are and where you need to be comes very late in the game," said Bhaskaran. "That's why the last few hours before impact are so critical. We need to execute some final rocket burns, called Impactor Targeting Maneuvers (ITMs), quickly. With Earth so far away, there is no chance to send new commands in time.


"So, instead, we have AutoNav do the job for us. It is essentially a cyber-astronaut that takes in all the pertinent information, makes its own decisions and performs the actions necessary to make sure we go splat where we want to go splat."


Currently, Bhaskaran is running simulations that make his virtual impactor go splat against the furrowed, organic-rich regolith of asteroid 1999 RQ36. The 1,600-foot-wide (500-meter-wide) space rock is the target of a proposed JPL mission called the Impactor for Surface and Interior Science (ISIS). The impactor spacecraft, which looks a little like a rocket-powered wedding ring, would hitch a free ride into space aboard the rocket carrying NASA's InSight mission to Mars. The impactor's trajectory would then loop around Mars and bear down on RQ36.


"One of the things that helps me sleep at night is that we know a lot about RQ36 because it is the target of another NASA mission called OSIRIS-REx," said Bhaskaran. "But it also provides some challenges because the scientists want us to hit the asteroid at a certain moment in time and at a certain location, so that the OSIRIS-REx spacecraft can be sure to monitor the results from a safe vantage point. It is a challenge but it's also really exciting."


The part of the ISIS mission Bhaskaran is most interested in is what happens after our rocket-festooned, cyber-hero rounds Mars and begins to close the distance with the asteroid at a speed of 8.4 miles per second (49,000 kilometers per hour). Over the next several months, the mission navigators would plan and execute several deep space maneuvers that refine the spacecraft's approach. Then, with only two hours to go, AutoNav would take over to make the final orbital changes.


"AutoNav's imaging system and its orbit determination algorithms will detect the asteroid and compute its location in space relative to the impactor," said Bhaskaran. "Without waiting to hear from us, it will plan for and execute three ITMs at 90 minutes, 30 minutes and then three minutes out. That last rocket firing will occur when the asteroid is only 1,500 miles [2,400 kilometers] away. Three minutes later, if all goes according to plan, the spacecraft hits like a ton of bricks."


While Bhaskaran loves ISIS for the navigation challenge it provides, the proposed mission's principal investigator likes what the out-of-this-world equivalent of the release of nine tons of TNT does to the surface -- and interior -- of an asteroid.


"We expect the crater excavated by the impact of ISIS could be around 100 feet across," said Chesley. "From its catbird seat in orbit around the asteroid, OSIRIS-REx, at its leisure, would not only be able to determine how big a hole there is, but also analyze the material thrown out during the impact."


The data would not only provide information on what makes up the asteroid, but how its orbit reacts to being hit by a NASA spacecraft.


"While the effect of ISIS on the orbit of asteroid 1999 RQ36 will be miniscule, it will be measurable," said Chesley. "Once we know how its orbit changes, no matter how small, we can make better assessments and plans to change some future asteroid's orbit if we ever need to do so. Of course, to get all these great leaps forward in understanding, we have to hit it in the first place."


Which leads us back to Bhaskaran and his hard drive laden full of hypervelocity impact simulations.


"We have confidence that whenever called upon, AutoNav will do its job," said Bhaskaran. "The trick is, we just don't tell AutoNav it's a one-way trip."


Bhaskaran will present his latest findings on guidance for hypervelocity impacts on Tuesday, April 16, at the International Academy of Astronautics' Planetary Defense Conference in Flagstaff, Ariz.


NASA detects, tracks and characterizes asteroids and comets passing relatively close to Earth using both ground- and space-based telescopes. The Near-Earth Object Observations Program, commonly called "Spaceguard," discovers these objects, characterizes a subset of them, and predicts their paths to determine if any could be potentially hazardous to our planet.


JPL manages the Near-Earth Object Program Office for NASA's Science Mission Directorate in Washington. Steve Chesley of JPL is leading the Impactor for Surface and Interior Science (ISIS) mission proposal. JPL is a division of the California Institute of Technology in Pasadena. NASA's Goddard Space Flight Center, Greenbelt, Md., manages the OSIRIS-Rex project.


More information about asteroids and near-Earth objects is at: http://www.jpl.nasa.gov/asteroidwatch , and on Twitter: @asteroidwatch .

DC Agle 818-393-9011

Jet Propulsion Laboratory, Pasadena, Calif.

agle@jpl.nasa.gov


2013-138
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Astronomers Discover Massive Star Factory in Early Universe

Astronomers Discover Massive Star Factory in Early Universe:

Artist's Impression of Starburst Galaxy
This artist's impression shows the "starburst" galaxy HFLS3. The galaxy appears as little more than a faint, red smudge in images from the Herschel space observatory. Image credit: ESA-C. Carreau
› Full image and caption

April 17, 2013

Astronomers, including Matt Bradford, Jamie Bock, Darren Dowell, Hien Nguyen and Jonas Zmuidzinas of NASA's Jet Propulsion Laboratory, Pasadena, Calif., have discovered a dust-filled, massive galaxy churning out stars when the cosmos was a mere 880 million years old. This is the earliest starburst galaxy ever observed.


The discovery, appearing in the April 18 issue of Nature, was made using the European Space Agency's Herschel space observatory, for which JPL helped build two instruments.


The first galaxies were small, then eventually merged together to form the behemoths we see in the present universe. Those smaller galaxies produced stars at a modest rate, and only later --when the universe was a couple of billion years old -- did the vast majority of larger galaxies begin to form and accumulate enough gas and dust to become prolific star factories. Indeed, astronomers have observed that these star factories, called starburst galaxies, became prevalent a couple of billion years after the big bang.


The newfound galaxy, called HFLS3, seems to defy this model, prodigiously producing stars when our universe was in its infancy. HFLS3 is about as massive as our Milky Way galaxy but produces stars at a rate 2,000 times greater. These stars are forming from interstellar gas remarkably rich in molecules such as carbon monoxide, ammonia and water.


Generating the mass equivalent of 2,900 suns per year, the galaxy is making stars at a rate as high as any galaxy in the universe, prompting the team to call it a "maximum-starburst" galaxy.


While the discovery of this single galaxy isn't enough to overturn current theories of galaxy formation, finding more galaxies like this one could challenge them, the astronomers say.


"This galaxy is just one spectacular example, but it's telling us that extremely vigorous star formation is possible early in the universe," said Bock, who is also a professor of physics at the California Institute of Technology in Pasadena and a coauthor of the paper.


Read the Caltech news release at
http://www.caltech.edu/content/astronomers-discover-massive-star-factory-early-universe . Read the European Space Agency release at: http://www.esa.int/Our_Activities/Space_Science/Herschel/Star_factory_in_the_early_Universe_challenges_galaxy_evolution_theory .


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 Caltech in Pasadena, supports the United States astronomical community. Caltech manages JPL for NASA.


More information is online at http://www.herschel.caltech.edu , http://www.nasa.gov/herschel and http://www.esa.int/SPECIALS/Herschel .

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


2013-139
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Galaxy Goes Green in Burning Stellar Fuel

Galaxy Goes Green in Burning Stellar Fuel:

Galaxy Packs Big Star-Making Punch
The tiny red spot in this image is one of the most efficient star-making galaxies ever observed, converting gas into stars at the maximum possible rate. The galaxy is shown here in an image from NASA's Wide-field Infrared Survey Explorer (WISE), which first spotted the rare galaxy in infrared light. Image credit: NASA/JPL-Caltech/STScI/IRAM
› Full image and caption

April 23, 2013

Astronomers have spotted the "greenest" of galaxies, one that converts fuel into stars with almost 100-percent efficiency.


The findings come from NASA's Wide-field Infrared Survey Explorer (WISE), NASA's Hubble Space Telescope and the IRAM Plateau de Bure interferometer in the French Alps.


"This galaxy is remarkably efficient," said Jim Geach of McGill University in Canada, lead author of a new study appearing in the Astrophysical Journal Letters. "It's converting its gas supply into new stars at the maximum rate thought possible."


Stars are formed out of collapsing clouds of gas in galaxies. In a typical galaxy, like the Milky Way, only a fraction of the total gas supply is actively forming stars, with the bulk of the fuel lying dormant. The gas is distributed widely throughout the galaxy, with most of the new stars being formed within discrete, dense 'knots' in the spiral arms.


In the galaxy, called SDSSJ1506+54, nearly all of the gas has been driven to the central core of the galaxy, where it has ignited in a powerful burst of star formation.


"We are seeing a rare phase of evolution that is the most extreme -- and most efficient -- yet observed," said Geach.


The results will provide a better understanding of how the central star-forming regions of galaxies take shape.


SDSSJ1506+54 jumped out at the researchers when they looked at it using data from WISE's all-sky infrared survey. Infrared light is pouring out of the galaxy, equivalent to more than a thousand billion times the energy of our sun. The galaxy is so distant it has taken the light nearly six billion years to reach us.


"Because WISE scanned the entire sky, it detected rare galaxies like this one that stand out from the rest," said Ned Wright of UCLA, the WISE principal investigator.


Hubble's visible-light observations revealed that the galaxy is extremely compact, with most of its light emanating from a region just a few hundred light-years across. That's a big star-making punch for such a little size.


"While this galaxy is forming stars at a rate hundreds of times faster than our Milky Way galaxy, the sharp vision of Hubble revealed that the majority of the galaxy's starlight is being emitted by a region with a diameter just a few percent that of the Milky Way," said Geach.


The team then used the IRAM Plateau de Bure Interferometer to measure the amount of gas in the galaxy. The ground-based telescope detected millimeter-wave light coming from carbon monoxide, an indicator of the presence of hydrogen gas, which is fuel for stars. Combining the rate of star formation derived with WISE, and the gas mass measured by IRAM, the scientists get a measure of the star-formation efficiency.


In regions of galaxies where new stars are forming, parts of gas clouds are collapsing due to gravity. When the gas is dense enough to squeeze atoms together and ignite nuclear fusion, a star is born. But this process can be halted by other newborn stars, as their winds and radiation blow the gas outward. The point at which this occurs sets the theoretical maximum for star formation. The galaxy SDSSJ1506+54 was found to be making stars right at this point, just before the gas clouds would otherwise be blown apart.


"We see some gas outflowing from this galaxy at millions of miles per hour, and this gas may have been blown away by the powerful radiation from the newly formed stars," said Ryan Hickox, an astrophysicist at Dartmouth College, Hanover, N.H., and a co-author on the study.


Why is SDSSJ1506+54 so unusual? Astronomers say they're catching the galaxy in a short-lived phase of evolution, possibly triggered by the merging of two galaxies into one. The star formation is so prolific that in a few tens of millions of years, the blink of an eye in a galaxy's life, the gas will be used up, and SDSSJ1506+54 will mature into a massive elliptical galaxy.


The scientists also used data from the Sloan Digital Sky Survey, the W.M. Keck Observatory on Mauna Kea, Hawaii, and the MMT Observatory on Mount Hopkins, Arizona.


For more information about WISE, visit: http://www.nasa.gov/wise . For more information about Hubble, visit: http://www.nasa.gov/hubble .

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


2013-144
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Herschel Links Water Around Jupiter to Comet Impact

Herschel Links Water Around Jupiter to Comet Impact:

Distribution of Water in Jupiter's Stratosphere
This map shows the distribution of water in the stratosphere of Jupiter as measured with the Herschel space observatory. White and cyan indicate highest concentration of water, and blue indicates lesser amounts. The map has been superimposed over an image of Jupiter taken at visible wavelengths with the NASA/ESA Hubble Space Telescope. Image credit: Water map: ESA/Herschel/T. Cavalié et al.; Jupiter image: NASA/ESA/Reta Beebe (New Mexico State University)
› Full image and caption

April 23, 2013

Astronomers have finally found direct proof that almost all water present in Jupiter's stratosphere, an intermediate atmospheric layer, was delivered by comet Shoemaker-Levy 9, which famously struck the planet in 1994.


The findings, based on new data from the Herschel space observatory, reveal more water in Jupiter's southern hemisphere, where the impacts occurred, than in the north. Herschel is a European Space Agency mission with important NASA participation.


The origin of water in the upper atmospheres of the solar system's giant planets has been debated for almost two decades. Astronomers were quite surprised at the discovery of water in the stratospheres of Jupiter, Saturn, Uranus and Neptune, which dates to observations performed with ESA's Infrared Space Observatory in 1997.


While the source of water in the lower layers of their atmospheres can be explained as internal, the presence of this molecule in their upper atmospheric layers is puzzling due to the scarcity of oxygen there. Its supply must have an external origin. Since then, astronomers have investigated several possible candidates that may have delivered water to these planets, from icy rings and satellites to interplanetary dust particles and cometary impacts.


Data from Herschel's Photodetecting Array Camera and Spectrometer (PACS), with the help of NASA's Infrared Telescope Facility, helped solve the mystery at Jupiter by showing an asymmetry in the distribution of water in its stratosphere, caused by the comet impact. Additional proof for a cometary source for the water came from Hershel's heterodyne instrument for the far infrared (HIFI), which probed the vertical profile of water in the stratosphere. NASA's Jet Propulsion Laboratory in Pasadena, Calif., helped build the HIFI instrument.


"The asymmetry between the two hemispheres suggests that water was delivered during a single event and rules out icy rings or moons as candidate sources," says Thibault Cavalié from the Laboratoire d'Astrophysique de Bordeaux, France, who led the study. "Local sources would provide a steady supply of water, which over time would lead to a hemispherically symmetric distribution in the stratosphere. Depending on whether the chemical species are transported in neutral or ionized form, local sources of water would result in higher concentrations either at the poles or along the equator, but not in a north-south asymmetry."


Read the full ESA news release at: http://www.esa.int/Our_Activities/Space_Science/Herschel/Herschel_links_Jupiter_s_water_to_comet_impact .


Herschel is a European Space Agency mission, with science instruments provided by consortia of European institutes and with important participation by NASA. NASA's Herschel Project Office is based at JPL. 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.


More information is online at http://www.herschel.caltech.edu , http://www.nasa.gov/herschel and http://www.esa.int/SPECIALS/Herschel .

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


2013-145
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NASA Invites the Public to Fly Along with Voyager

NASA Invites the Public to Fly Along with Voyager:

Fly Along with Voyager to Interstellar Space
The public will be able to fly along with NASA's Voyager spacecraft as the twin probes head towards interstellar space, which is the space between stars. As indicated in this artist's concept, a regularly updated gauge using data from the two spacecraft will indicate the levels of particles that originate from far outside our solar system and those that originate from inside our solar bubble. Those are two of the three signs scientists expect to see in interstellar space. The other sign is a change in the direction of the magnetic field. Image credit: NASA/JPL-Caltech
› Larger image

April 24, 2013

A gauge on the Voyager home page, http://voyager.jpl.nasa.gov, tracks levels of two of the three key signs scientists believe will appear when the spacecraft leave our solar neighborhood and enter interstellar space.


When the three signs are verified, scientists will know that one of the Voyagers has hurtled beyond the magnetic bubble the sun blows around itself, which is known as the heliosphere.


The gauge indicates the level of fast-moving charged particles, mainly protons, originating from far outside the heliosphere, and the level of slower-moving charged particles, also mainly protons, from inside the heliosphere. If the level of outside particles jumps dramatically and the level of inside particles drops precipitously, and these two levels hold steady, that means one of the spacecraft is closing in on the edge of interstellar space. These data are updated every six hours.


Scientists then need only see a change in the direction of the magnetic field to confirm that the spacecraft has sailed beyond the breath of the solar wind and finally arrived into the vast cosmic ocean between stars. The direction of the magnetic field, however, requires periodic instrument calibrations and complicated analyses. These analyses typically take a few months to return after the charged particle data are received on Earth.


Voyager 1, the most distant human-made spacecraft, appears to have reached this last region before interstellar space, which scientists have called "the magnetic highway." Inside particles are zooming out and outside particles are zooming in. However, Voyager 1 has not yet seen a change in the direction of the magnetic field, so the consensus among the Voyager team is that it has not yet left the heliosphere.


Voyager 2, the longest-operating spacecraft, but not as distant as Voyager 1, does not yet appear to have reached the magnetic highway, though it has recently seen some modest drops of the inside particle level.


NASA's Eyes on the Solar System program, a Web-based, video-game-like tool to journey with NASA's spacecraft through the solar system, has added a Voyager module that takes viewers along for a ride with Voyager 1 as it explores the outer limits of the heliosphere. Time has been sped up to show one day per second. Rolls and other maneuvers are incorporated into the program, based on actual spacecraft navigation data. The charged particle data are also shown. Visit that module at:
http://1.usa.gov/13uYqGP .


The Voyager spacecraft were built and continue to be operated by NASA's Jet Propulsion Laboratory, Pasadena, Calif. Caltech manages JPL for NASA. The Voyager missions are a part of NASA's Heliophysics System Observatory, sponsored by the Heliophysics Division of the Science Mission Directorate at NASA Headquarters in Washington.


For more information about the Voyager spacecraft, visit: http://www.nasa.gov/voyager and http://voyager.jpl.nasa.gov .

Jia-Rui C. Cook 818-354-0850

Jet Propulsion Laboratory, Pasadena, Calif.

jccook@jpl.nasa.gov


2013-146
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'Tis the Season -- for Plasma Changes at Saturn

'Tis the Season -- for Plasma Changes at Saturn:

Artist Concept of Particle Population in Saturn's Magnetosphere
This is an artist's concept of the Saturnian plasma sheet based on data from Cassini magnetospheric imaging instrument. It shows Saturn's embedded "ring current," an invisible ring of energetic ions trapped in the planet's magnetic field. Image credit: NASA/JPL/JHUAPL
› Full image and caption

May 02, 2013

Researchers working with data from NASA's Cassini spacecraft have discovered one way the bubble of charged particles around Saturn -- known as the magnetosphere -- changes with the planet's seasons. The finding provides an important clue for solving a riddle about the planet's naturally occurring radio signal. The results might also help scientists better understand variations in Earth's magnetosphere and Van Allen radiation belts, which affect a variety of activities at Earth, ranging from space flight safety to satellite and cell phone communications.


The paper, just published in the Journal of Geophysical Research, is led by Tim Kennelly, an undergraduate physics and astronomy major at the University of Iowa, Iowa City, who is working with Cassini's radio and plasma wave science team.


In data collected by Cassini from July 2004 to December 2011, Kennelly and his colleagues examined "flux tubes," structures composed of hot, electrically charged gas called plasma, which funnel charged particles in towards Saturn. Focusing on the tubes when they initially formed and before they had a chance to dissipate under the influence of the magnetosphere, the scientists found that the occurrence of the tubes correlates with radio wave patterns in the northern and southern hemisphere depending upon the season. This seasonal effect is roughly similar to the way Earth's northern lights appear more frequently in the spring and autumn months.


Radio emissions have been used to measure Jupiter's rotation period reliably, and scientists thought it would also help them determine Saturn's rotation period. To their chagrin, however, the pattern has varied over the visits by different spacecraft and even in radio emissions originating in the northern and southern hemispheres. The new results could help scientists hone in on why these signals vary the way they do.


For more on the finding, go to: http://now.uiowa.edu/2013/03/telling-time-saturn .


The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and the Italian Space Agency. NASA's Jet Propulsion Laboratory in Pasadena, Calif., manages the mission for the agency's Science Mission Directorate in Washington. The radio and plasma wave science team is based at the University of Iowa, Iowa City, where the instrument was built. JPL is a division of the California Institute of Technology, Pasadena.


For more information about the Cassini-Huygens mission, visit http://saturn.jpl.nasa.gov and http://www.nasa.gov/cassini.

Jia-Rui Cook 818-354-0850

Jet Propulsion Laboratory, Pasadena, Calif.

jccook@jpl.nasa.gov


Gary Galluzzo 319-384-0009

University of Iowa, Iowa City

gary-galluzzo@uiowa.edu


2013-153
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Milky Way Black Hole Snacks on Hot Gas

Milky Way Black Hole Snacks on Hot Gas:

This artist's concept illustrates the frenzied activity at the core of our Milky Way galaxy.
This artist's concept illustrates the frenzied activity at the core of our Milky Way galaxy. The galactic center hosts a supermassive black hole in the region known as Sagittarius A*, or Sgr A*, with a mass of about four million times that of our sun. The Herschel space observatory has made detailed observations of surprisingly hot gas that may be orbiting or falling toward the supermassive black hole. Image credits: ESA-C. Carreau
› Full image and caption

May 07, 2013

The Herschel space observatory has made detailed observations of surprisingly hot gas that may be orbiting or falling towards the supermassive black hole lurking at the center of our Milky Way galaxy. Herschel is a European Space Agency mission with important NASA participation.


"The black hole appears to be devouring the gas," said Paul Goldsmith, the U.S. project scientist for Herschel at NASA's Jet Propulsion Laboratory, Pasadena, Calif. "This will teach us about how supermassive black holes grow."


Our galaxy's black hole is located in a region known as Sagittarius A* -- or Sgr A* for short -- which is a nearby source of radio waves. The black hole has a mass about four million times that of our sun and lies roughly 26,000 light-years away from our solar system.


Even at that distance, it is a few hundred times closer to us than any other galaxy with an active black hole at its center, making it the ideal natural laboratory to study the environment around these enigmatic objects. At Herschel's far-infrared wavelengths, scientists can peer through the dust in our galaxy and study the turbulent innermost region of the galaxy in great detail.


The biggest surprise was the hot gas in the innermost central region of the galaxy. At least some of it is 1,832 degrees Fahrenheit (around 1,000 degrees Celsius), much hotter than typical interstellar clouds, which are usually only a few tens of degrees above absolute zero, or minus 460 degrees Fahrenheit (minus 273 degrees Celsius).


The team hypothesizes that emissions from strong shocks in highly magnetized gas in the region may be a significant contributor to the high temperatures. Such shocks can be generated in collisions between gas clouds, or in material flowing at high speeds.


Using near-infrared observations, other astronomers have spotted a separate, compact cloud of gas amounting to just a few Earth masses spiralling toward the black hole. Located much closer to the black hole than the reservoir of material studied by Herschel in this work, it may finally be gobbled up later this year.


Spacecraft, including NASA's Nuclear Spectroscopic Telescope Array (NuSTAR) and the Chandra X-ray Observatory, will be waiting to spot any X-ray burps as the black hole enjoys its feast.


Read the full ESA news release at http://www.esa.int/Our_Activities/Space_Science/Herschel/Herschel_finds_hot_gas_on_the_menu_for_Milky_Way_s_black_hole .


Herschel is a European Space Agency 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.


More information is online at http://www.herschel.caltech.edu , http://www.nasa.gov/herschel and http://www.esa.int/SPECIALS/Herschel .

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


2013-156
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Sifting Through the Atmospheres of Far-off Worlds

Sifting Through the Atmospheres of Far-off Worlds:

Planetary Family Portrait
This image shows the HR 8799 planets with starlight optically suppressed and data processing conducted to remove residual starlight. The star is at the center of the blackened circle in the image. The four spots indicated with the letters b through e are the planets. This is a composite image using 30 wavelengths of light and was obtained over a period of 1.25 hours on June 14 and 15, 2012. Image courtesy of Project 1640
› Full image and caption

May 09, 2013

Gone are the days of being able to count the number of known planets on your fingers. Today, there are more than 800 confirmed exoplanets -- planets that orbit stars beyond our sun -- and more than 2,700 other candidates. What are these exotic planets made of? Unfortunately, you cannot stack them in a jar like marbles and take a closer look. Instead, researchers are coming up with advanced techniques for probing the planets' makeup.


One breakthrough to come in recent years is direct imaging of exoplanets. Ground-based telescopes have begun taking infrared pictures of the planets posing near their stars in family portraits. But to astronomers, a picture is worth even more than a thousand words if its light can be broken apart into a rainbow of different wavelengths.


Those wishes are coming true as researchers are beginning to install infrared cameras on ground-based telescopes equipped with spectrographs. Spectrographs are instruments that spread an object's light apart, revealing signatures of molecules. Project 1640, partly funded by NASA's Jet Propulsion Laboratory, Pasadena, Calif., recently accomplished this goal using the Palomar Observatory near San Diego.


"In just one hour, we were able to get precise composition information about four planets around one overwhelmingly bright star," said Gautam Vasisht of JPL, co-author of the new study appearing in the Astrophysical Journal. "The star is a hundred thousand times as bright as the planets, so we've developed ways to remove that starlight and isolate the extremely faint light of the planets."


Along with ground-based infrared imaging, other strategies for combing through the atmospheres of giant planets are being actively pursued as well. For example, NASA's Spitzer and Hubble space telescopes monitor planets as they cross in front of their stars, and then disappear behind. NASA's upcoming James Webb Space Telescope will use a comparable strategy to study the atmospheres of planets only slightly larger than Earth.


In the new study, the researchers examined HR 8799, a large star orbited by at least four known giant, red planets. Three of the planets were among the first ever directly imaged around a star, thanks to observations from the Gemini and Keck telescopes on Mauna Kea, Hawaii, in 2008. The fourth planet, the closest to the star and the hardest to see, was revealed in images taken by the Keck telescope in 2010.


That alone was a tremendous feat considering that all planet discoveries up until then had been made through indirect means, for example by looking for the wobble of a star induced by the tug of planets.


Those images weren't enough, however, to reveal any information about the planets' chemical composition. That's where spectrographs are needed -- to expose the "fingerprints" of molecules in a planet's atmosphere. Capturing a distant world's spectrum requires gathering even more planet light, and that means further blocking the glare of the star.


Project 1640 accomplished this with a collection of instruments, which the team installs on the ground-based telescopes each time they go on "observing runs." The instrument suite includes a coronagraph to mask out the starlight; an advanced adaptive optics system, which removes the blur of our moving atmosphere by making millions of tiny adjustments to two deformable telescope mirrors; an imaging spectrograph that records 30 images in a rainbow of infrared colors simultaneously; and a state-of-the-art wave front sensor that further adjusts the mirrors to compensate for scattered starlight.


"It's like taking a single picture of the Empire State Building from an airplane that reveals a bump on the sidewalk next to it that is as high as an ant," said Ben R. Oppenheimer, lead author of the new study and associate curator and chair of the Astrophysics Department at the American Museum of Natural History, N.Y., N.Y.


Their results revealed that all four planets, though nearly the same in temperature, have different compositions. Some, unexpectedly, do not have methane in them, and there may be hints of ammonia or other compounds that would also be surprising. Further theoretical modeling will help to understand the chemistry of these planets.


Meanwhile, the quest to obtain more and better spectra of exoplanets continues. Other researchers have used the Keck telescope and the Large Binocular Telescope near Tucson, Ariz., to study the emission of individual planets in the HR8799 system. In addition to the HR 8799 system, only two others have yielded images of exoplanets. The next step is to find more planets ripe for giving up their chemical secrets. Several ground-based telescopes are being prepared for the hunt, including Keck, Gemini, Palomar and Japan's Subaru Telescope on Mauna Kea, Hawaii.


Ideally, the researchers want to find young planets that still have enough heat left over from their formation, and thus more infrared light for the spectrographs to see. They also want to find planets located far from their stars, and out of the blinding starlight. NASA's infrared Spitzer and Wide-field Infrared Survey Explorer (WISE) missions, and its ultraviolet Galaxy Evolution Explorer, now led by the California Institute of Technology, Pasadena, have helped identify candidate young stars that may host planets meeting these criteria.


"We're looking for super-Jupiter planets located faraway from their star," said Vasisht. "As our technique develops, we hope to be able to acquire molecular compositions of smaller, and slightly older, gas planets."


Still lower-mass planets, down to the size of Saturn, will be targets for imaging studies by the James Webb Space Telescope.


"Rocky Earth-like planets are too small and close to their stars for the current technology, or even for James Webb to detect. The feat of cracking the chemical compositions of true Earth analogs will come from a future space mission such as the proposed Terrestrial Planet Finder," said Charles Beichman, a co-author of the P1640 result and executive director of NASA's Exoplanet Science Institute at Caltech.


Though the larger, gas planets are not hospitable to life, the current studies are teaching astronomers how the smaller, rocky ones form.


"The outer giant planets dictate the fate of rocky ones like Earth. Giant planets can migrate in toward a star, and in the process, tug the smaller, rocky planets around or even kick them out of the system. We're looking at hot Jupiters before they migrate in, and hope to understand more about how and when they might influence the destiny of the rocky, inner planets," said Vasisht.


NASA's Exoplanet Science Institute manages time allocation on the Keck telescope for NASA. JPL manages NASA's Exoplanet Exploration program office. Caltech manages JPL for NASA.


A visualization from the American Museum of Natural History showing where the HR 8799 system is in relation to our solar system is online at http://www.youtube.com/watch?v=yDNAk0bwLrU .


More information about exoplanets and NASA's planet-finding program is at http://planetquest.jpl.nasa.gov .

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


2013-057
Posted by Nelio Inacio at 5:38 PM 0 comments
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Cassini Shapes First Global Topographic Map of Titan

Cassini Shapes First Global Topographic Map of Titan:

Global Topographic Map of Titan
These polar maps show the first global, topographic mapping of Saturn's moon Titan, using data from NASA's Cassini mission. To create these maps, scientists employed a mathematical process called splining, which uses smooth curved surfaces to "join" the areas between grids of existing topography profiles obtained by Cassini's radar instrument.Image credit: NASA/JPL-Caltech/ASI/JHUAPL/Cornell/Weizmann
› Full image and caption

May 15, 2013

Scientists have created the first global topographic map of Saturn's moon Titan, giving researchers a valuable tool for learning more about one of the most Earth-like and interesting worlds in the solar system. The map was just published as part of a paper in the journal Icarus.


Titan is Saturn's largest moon - with a radius of about 1,600 miles (2,574 kilometers), it's bigger than planet Mercury - and is the second-largest moon in the solar system. Scientists care about Titan because it's the only moon in the solar system known to have clouds, surface liquids and a mysterious, thick atmosphere. The cold atmosphere is mostly nitrogen, like Earth's, but the organic compound methane on Titan acts the way water vapor does on Earth, forming clouds and falling as rain and carving the surface with rivers. Organic chemicals, derived from methane, are present in Titan's atmosphere, lakes and rivers and may offer clues about the origins of life.


"Titan has so much interesting activity - like flowing liquids and moving sand dunes - but to understand these processes it's useful to know how the terrain slopes," said Ralph Lorenz, a member of the Cassini radar team based at the Johns Hopkins University Applied Physics Laboratory, Laurel, Md., who led the map-design team. "It's especially helpful to those studying hydrology and modeling Titan's climate and weather, who need to know whether there is high ground or low ground driving their models."


Titan's thick haze scatters light in ways that make it very hard for remote cameras to "see" landscape shapes and shadows, the usual approach to measuring topography on planetary bodies. Virtually all the data we have on Titan comes from NASA's Saturn-orbiting Cassini spacecraft, which has flown past the moon nearly 100 times over the past decade. On many of those flybys, Cassini has used a radar imager, which can peer through the haze, and the radar data can be used to estimate the surface height.


"With this new topographic map, one of the most fascinating and dynamic worlds in our solar system now pops out in 3-D," said Steve Wall, the deputy team lead of Cassini's radar team, based at NASA's Jet Propulsion Laboratory in Pasadena, Calif. "On Earth, rivers, volcanoes and even weather are closely related to heights of surfaces - we're now eager to see what we can learn from them on Titan."


There are challenges, however. "Cassini isn't orbiting Titan," Lorenz said. "We have only imaged about half of Titan's surface, and multiple 'looks' or special observations are needed to estimate the surface heights. If you divided Titan into 1-degree by 1-degree [latitude and longitude] squares, only 11 percent of those squares have topography data in them."


Lorenz's team used a mathematical process called splining - effectively using smooth, curved surfaces to "join" the areas between grids of existing data. "You can take a spot where there is no data, look how close it is to the nearest data, and use various approaches of averaging and estimating to calculate your best guess," he said. "If you pick a point, and all the nearby points are high altitude, you'd need a special reason for thinking that point would be lower. We're mathematically papering over the gaps in our coverage."


The estimations fit with current knowledge of the moon - that its polar regions are "lower" than areas around the equator, for example - but connecting those points allows scientists to add new layers to their studies of Titan's surface, especially those modeling how and where Titan's rivers flow, and the seasonal distribution of its methane rainfall. "The movement of sands and the flow of liquids are influenced by slopes, and mountains can trigger cloud formation and therefore rainfall. This global product now gives modelers a convenient description of this key factor in Titan's dynamic climate system," Lorenz said.


The most recent data used to compile the map is from 2012; Lorenz says it could be worth revising when the Cassini mission ends in 2017, when more data will have accumulated, filling some of the gaps in present coverage. "We felt we couldn't wait and should release an interim product," he says. "The community has been hoping to get this for a while. I think it will stimulate a lot of interesting work."


The Cassini-Huygens mission is a cooperative project of NASA, the European Space Agency and ASI, the Italian Space Agency. JPL, a division of the California Institute of Technology in Pasadena, manages the mission for NASA's Science Mission Directorate, Washington. The radar instrument was built by JPL and the Italian Space Agency, working with team members from the United States and several European countries.

Jia-Rui Cook 818-354-0850

Jet Propulsion Laboratory, Pasadena, Calif.

jccook@jpl.nasa.gov


Michael Buckley 240-228-7536

Johns Hopkins Applied Physics Laboratory, Laurel, Md.

Michael.buckley@jhuapl.edu


2013-161
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Asteroid 1998 QE2 to Sail Past Earth Nine Times Larger Than Cruise Ship

Asteroid 1998 QE2 to Sail Past Earth Nine Times Larger Than Cruise Ship:

The orbit of asteroid 1998 QE2.
The orbit of asteroid 1998 QE2.
Image credit:
NASA/JPL-Caltech
› Larger image

May 15, 2013

On May 31, 2013, asteroid 1998 QE2 will sail serenely past Earth, getting no closer than about 3.6 million miles (5.8 million kilometers), or about 15 times the distance between Earth and the moon. And while QE2 is not of much interest to those astronomers and scientists on the lookout for hazardous asteroids, it is of interest to those who dabble in radar astronomy and have a 230-foot (70-meter) -- or larger -- radar telescope at their disposal.


"Asteroid 1998 QE2 will be an outstanding radar imaging target at Goldstone and Arecibo and we expect to obtain a series of high-resolution images that could reveal a wealth of surface features," said radar astronomer Lance Benner, the principal investigator for the Goldstone radar observations from NASA's Jet Propulsion Laboratory in Pasadena, Calif. "Whenever an asteroid approaches this closely, it provides an important scientific opportunity to study it in detail to understand its size, shape, rotation, surface features, and what they can tell us about its origin. We will also use new radar measurements of the asteroid's distance and velocity to improve our calculation of its orbit and compute its motion farther into the future than we could otherwise."


The closest approach of the asteroid occurs on May 31 at 1:59 p.m. Pacific (4:59 p.m. Eastern / 20:59 UTC). This is the closest approach the asteroid will make to Earth for at least the next two centuries. Asteroid 1998 QE2 was discovered on Aug. 19, 1998, by the Massachusetts Institute of Technology Lincoln Near Earth Asteroid Research (LINEAR) program near Socorro, New Mexico.


The asteroid, which is believed to be about 1.7 miles (2.7 kilometers) or nine Queen Elizabeth 2 ship-lengths in size, is not named after that 12-decked, transatlantic-crossing flagship for the Cunard Line. Instead, the name is assigned by the NASA-supported Minor Planet Center in Cambridge, Mass., which gives each newly discovered asteroid a provisional designation starting with the year of first detection, along with an alphanumeric code indicating the half-month it was discovered, and the sequence within that half-month.


Radar images from the Goldstone antenna could resolve features on the asteroid as small as 12 feet (3.75 meters) across, even from 4 million miles away.


"It is tremendously exciting to see detailed images of this asteroid for the first time," said Benner. "With radar we can transform an object from a point of light into a small world with its own unique set of characteristics. In a real sense, radar imaging of near-Earth asteroids is a fundamental form of exploring a whole class of solar system objects."


Asteroids, which are always exposed to the sun, can be shaped like almost anything under it. Those previously imaged by radar and spacecraft have looked like dog bones, bowling pins, spheroids, diamonds, muffins, and potatoes. To find out what 1998 QE2 looks like, stay tuned. Between May 30 and June 9, radar astronomers using NASA's 230-foot-wide (70 meter) Deep Space Network antenna at Goldstone, Calif., and the Arecibo Observatory in Puerto Rico, are planning an extensive campaign of observations. The two telescopes have complementary imaging capabilities that will enable astronomers to learn as much as possible about the asteroid during its brief visit near Earth.


NASA places a high priority on tracking asteroids and protecting our home planet from them. In fact, the U.S. has the most robust and productive survey and detection program for discovering near-Earth objects. To date, U.S. assets have discovered over 98 percent of the known NEOs.


In 2012, the NEO budget was increased from $6 million to $20 million. Literally dozens of people are involved with some aspect of near-Earth object (NEO) research across NASA and its centers. Moreover, there are many more people involved in researching and understanding the nature of asteroids and comets, including those that come close to the Earth, plus those who are trying to find and track them in the first place.


In addition to the resources NASA puts into understanding asteroids, it also partners with other U.S. government agencies, university-based astronomers, and space science institutes across the country that are working to track and better understand these objects, often with grants, interagency transfers and other contracts from NASA.


NASA's Near-Earth Object Program at NASA Headquarters, Washington, manages and funds the search, study, and monitoring of asteroids and comets whose orbits periodically bring them close to Earth. JPL manages the Near-Earth Object Program Office for NASA's Science Mission Directorate in Washington. JPL is a division of the California Institute of Technology in Pasadena.


In 2016, NASA will launch a robotic probe to one of the most potentially hazardous of the known NEOs. The OSIRIS-REx mission to asteroid (101955) Bennu will be a pathfinder for future spacecraft designed to perform reconnaissance on any newly-discovered threatening objects. Aside from monitoring potential threats, the study of asteroids and comets enables a valuable opportunity to learn more about the origins of our solar system, the source of water on Earth, and even the origin of organic molecules that lead to the development of life.


NASA recently announced developing a first-ever mission to identify, capture and relocate an asteroid for human exploration. Using game-changing technologies advanced by the Administration, this mission would mark an unprecedented technological achievement that raises the bar of what humans can do in space. Capturing and redirecting an asteroid will integrate the best of NASA's science, technology and human exploration capabilities and draw on the innovation of America's brightest scientists and engineers.


More information about asteroids and near-Earth objects is available at:
http://neo.jpl.nasa.gov/ ,
http://www.jpl.nasa.gov/asteroidwatch and via Twitter at http://www.twitter.com/asteroidwatch .


More information about asteroid radar research is at: http://echo.jpl.nasa.gov/


More information about the Deep Space Network is at: http://deepspace.jpl.nasa.gov/dsn .

DC Agle 818-393-9011
Jet Propulsion Laboratory, Pasadena, Calif.
agle@jpl.nasa.gov


2013-163
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Galaxy's Ring of Fire

Galaxy's Ring of Fire:

Galactic Wheels within Wheels
How many rings do you see in this new image of the galaxy Messier 94, also known as NGC 4736? While at first glance one might see a number of them, astronomers believe there is just one. This image was captured in infrared light by NASA's Spitzer Space Telescope. Image credit: NASA/JPL-Caltech
› Full image and caption

May 16, 2013

Johnny Cash may have preferred this galaxy's burning ring of fire to the one he sang about falling into in his popular song. The "starburst ring" seen at center in red and yellow hues is not the product of love, as in the song, but is instead a frenetic region of star formation.


The galaxy, a spiral beauty called Messier 94, is located about 17 million light-years away. In this image from NASA's Spitzer Space Telescope, infrared light is represented in different colors, with blue having the shortest wavelengths and red, the longest.


Starburst rings like this can often be triggered by gravitational encounters with other galaxies but, in this case, may have instead been caused by the galaxy's oval shape. Gas in the ring is being converted into hot, young stars, which then warm the dust, causing it to glow with infrared light.


The outer, faint blue ring around the galaxy might be an optical illusion. Astronomers think that two separate spiral arms appear as a single unbroken ring when viewed from our position in space.


NASA's Jet Propulsion Laboratory, Pasadena, Calif., manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate, Washington. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology in Pasadena. Data are archived at the Infrared Science Archive housed at the Infrared Processing and Analysis Center at Caltech. Caltech manages JPL for NASA. For more information about Spitzer, visit http://spitzer.caltech.edu and http://www.nasa.gov/spitzer .

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

Whitney.Clavin@jpl.nasa.gov


2013-165
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Herschel Space Observatory Finds Galaxy Mega Merger

Herschel Space Observatory Finds Galaxy Mega Merger:

The Making of a Giant Galaxy
Several telescopes have teamed up to discover a rare and massive merging of two galaxies that took place when the universe was just 3 billion years old (its current age is about 14 billion years). The galaxies, collectively called HXMM01, are churning out the equivalent of 2,000 suns a year. By comparison, our Milky Way hatches about two to three suns a year. The total number of stars in both colliding galaxies averages out to about 400 billion suns. Image credit: ESA/NASA/JPL-Caltech/UC Irvine/STScI/Keck/NRAO/SAO
› Full image and caption

May 22, 2013

PASADENA, Calif. - A massive and rare merging of two galaxies has been spotted in images taken by the Herschel space observatory, a European Space Agency mission with important NASA participation.


Follow-up studies by several telescopes on the ground and in space, including NASA's Hubble Space Telescope and Spitzer Space Telescope, tell a tale of two faraway galaxies intertwined and furiously making stars. Eventually, the duo will settle down to form one super-giant elliptical galaxy.


The findings help explain a mystery in astronomy. Back when our universe was 3 billion to 4 billion years old, it was populated with large reddish elliptical-shaped galaxies made up of old stars. Scientists have wondered whether those galaxies built up slowly over time through the acquisitions of smaller galaxies, or formed more rapidly through powerful collisions between two large galaxies.


The new findings suggest massive mergers are responsible for the giant elliptical galaxies.


"We're looking at a younger phase in the life of these galaxies -- an adolescent burst of activity that won't last very long," said Hai Fu of the University of California at Irvine, who is lead author of a new study describing the results. The study is published in the May 22 online issue of Nature.


"These merging galaxies are bursting with new stars and completely hidden by dust," said co-author Asantha Cooray, also of the University of California at Irvine. "Without Herschel's far-infrared detectors, we wouldn't have been able to see through the dust to the action taking place behind."


Herschel, which operated for almost four years, was designed to see the longest-wavelength infrared light. As expected, it recently ran out of the liquid coolant needed to chill its delicate infrared instruments. While its mission in space is over, astronomers still are scrutinizing the data, and further discoveries are expected.


In the new study, Herschel was used to spot the colliding galaxies, called HXMM01, located about 11 billion light-years from Earth, during a time when our universe was about 3 billion years old. At first, astronomers thought the two galaxies were just warped, mirror images of one galaxy. Such lensed galaxies are fairly common in astronomy and occur when the gravity from a foreground galaxy bends the light from a more distant object. After a thorough investigation, the team realized they were actually looking at a massive galaxy merger.


Follow-up characterization revealed the merging galaxies are churning out the equivalent of 2,000 stars a year. By comparison, our Milky Way hatches about two to three stars a year. The total number of stars in both colliding galaxies averages out to about 400 billion.


Mergers are fairly common in the cosmos, but this particular event is unusual because of the prolific amounts of gas and star formation, and the sheer size of the merger at such a distant epoch.


The results go against the more popular model explaining how the biggest galaxies arise: through minor acquisitions of small galaxies. Instead, mega smash-ups may be doing the job.


NASA's Herschel Project Office is based at the agency's Jet Propulsion Laboratory in Pasadena, Calif., which contributed mission-enabling technology for two of Herschel's three science instruments. JPL is a division of the California Institute of Technology, Pasadena.


For more information about Herschel, visit: http://www.nasa.gov/herschel and http://www.esa.int/SPECIALS/Herschel .

Whitney Clavin 818-354-4673

Jet Propulsion Laboratory, Pasadena, Calif.

whitney.clavin@jpl.nasa.gov


J.D. Harrington 202-358-5241

NASA Headquarters, Washington

j.d.harrington@nasa.gov


2013-171
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