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  • NASA Invites the Public to Fly Along with Voyager
    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 although 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

    Original URL path: http://www.lpi.usra.edu/features/voyager/042513/ (2016-02-15)
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  • Sifting Through the Atmospheres of Far-Off Worlds
    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 groundbased 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 in New York Their results revealed that all four planets although 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 Arizona to study the emission of individual planets in the HR 8799 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 groundbased 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

    Original URL path: http://www.lpi.usra.edu/features/exoplanet/051313/ (2016-02-15)
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  • Blame it on the Rain (from Saturn’s Rings)
    The study also helps scientists better understand the origin and evolution of Saturn s ring system and changes in the planet s atmosphere It turns out that a major driver of Saturn s ionospheric environment and climate across vast reaches of the planet are ring particles located some 36 000 miles 60 000 kilometers overhead said Kevin Baines a co author on the paper based at NASA s Jet Propulsion Laboratory in Pasadena California The ring particles affect both what species of particles are in this part of the atmosphere and where it is warm or cool In the early 1980s images from NASA s Voyager spacecraft showed two to three dark bands on Saturn and scientists theorized that water could have been showering down into those bands from the rings Those bands were not seen again until this team observed the planet in near infrared wavelengths with the W M Keck Observatory on Mauna Kea in Hawaii in April 2011 The effect was difficult to discern because it involves looking for a subtle emission from bright parts of Saturn It required an instrument like that on Keck which can split up a large range of light The ring rain s effect occurs in Saturn s ionosphere where charged particles are produced when the otherwise neutral atmosphere is exposed to a flow of energetic particles or solar radiation When the scientists tracked the pattern of emissions of a particular hydrogen ion with three protons triatomic hydrogen they expected to see a uniform planet wide infrared glow What they observed instead was a series of light and dark bands with areas of reduced emission corresponding to water dense portions of Saturn s rings and areas of high emission corresponding to gaps in the rings They surmised that charged water particles from

    Original URL path: http://www.lpi.usra.edu/features/saturn/041113/ (2016-02-15)
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  • NASA Team Investigates Complex Chemistry at Titan
    system in the early 1980s that Titan Saturn s largest moon has a thick hazy atmosphere with hydrocarbons including methane and ethane These simple organic molecules can develop into smog like airborne molecules with carbon nitrogen hydrogen bonds which astronomer Carl Sagan called tholins We ve known that Titan s upper atmosphere is hospitable to the formation of complex organic molecules said co author Mark Allen principal investigator of the JPL Titan team that is a part of the NASA Astrobiology Institute headquartered at Ames Research Center Now we know that sunlight in the Titan lower atmosphere can kick start more complex organic chemistry in liquids and solids rather than just in gases The team examined an ice form of dicyanoacetylene a molecule detected on Titan that is related to a compound that turned brown after being exposed to ambient light in Allen s lab 40 years ago In this latest experiment dicyanoacetylene was exposed to laser light at wavelengths as long as 355 nanometers Light of that wavelength can filter down to Titan s lower atmosphere at a modest intensity somewhat like the amount of light that comes through protective glasses when Earthlings view a solar eclipse Gudipati said The result was the formation of a brownish haze between the two panes of glass containing the experiment confirming that organic ice photochemistry at conditions like Titan s lower atmosphere could produce tholins The complex organics could coat the rocks of water ice at Titan s surface and they could possibly seep through the crust to a liquid water layer under Titan s surface In previous laboratory experiments tholins like these were exposed to liquid water over time and developed into biologically significant molecules such as amino acids and the nucleotide bases that form RNA These results suggest that the

    Original URL path: http://www.lpi.usra.edu/features/titan/040413/ (2016-02-15)
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  • Saturn is Like an Antiques Shop, Cassini Suggests
    and also colors which are the signs of non water and organic materials are distributed throughout the saturnian system The spectrometer s data in the visible part of the light spectrum show that coloring on the rings and moons generally is only skin deep Using its infrared range VIMS also detected abundant water ice too much to have been deposited by comets or other recent means So the authors deduce that the water ices must have formed around the time of the birth of the solar system because Saturn orbits the Sun beyond the so called snow line Out beyond the snow line in the outer solar system where Saturn resides the environment is conducive to preserving water ice like a deep freezer Inside the solar system s snow line the environment is much closer to the Sun s warm glow and ices and other volatiles dissipate more easily The colored patina on the ring particles and moons roughly corresponds to their location in the Saturn system For Saturn s inner ring particles and moons water ice spray from the geyser moon Enceladus has a whitewashing effect Farther out the scientists found that the surfaces of Saturn s moons generally were redder the farther they orbited from Saturn Phoebe one of Saturn s outer moons and an object thought to originate in the far off Kuiper belt seems to be shedding reddish dust that eventually rouges the surface of nearby moons such as Hyperion and Iapetus A rain of meteoroids from outside the system appears to have turned some parts of the main ring system notably the part of the main rings known as the B ring a subtle reddish hue Scientists think the reddish color could be oxidized iron rust or polycyclic aromatic hydrocarbons which could be progenitors of

    Original URL path: http://www.lpi.usra.edu/features/saturn/040413/ (2016-02-15)
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  • Curiosity Mars Rover Sees Trend In Water Presence
    and minerals can be detected and mapped using the Mastcam s near infrared filters Ratios of brightness in different Mastcam near infrared wavelengths can indicate the presence of some hydrated minerals The technique was used to check rocks in the Yellowknife Bay area where Curiosity s drill last month collected the first powder from the interior of a rock on Mars Some rocks in Yellowknife Bay are crisscrossed with bright veins With Mastcam we see elevated hydration signals in the narrow veins that cut many of the rocks in this area said Melissa Rice of the California Institute of Technology Pasadena These bright veins contain hydrated minerals that are different from the clay minerals in the surrounding rock matrix The Russian made Dynamic Albedo of Neutrons DAN instrument on Curiosity detects hydrogen beneath the rover At the rover s very dry study area on Mars the detected hydrogen is mainly in water molecules bound into minerals We definitely see signal variation along the traverse from the landing point to Yellowknife Bay said DAN Deputy Principal Investigator Maxim Litvak of the Space Research Institute Moscow More water is detected at Yellowknife Bay than earlier on the route Even within Yellowknife Bay we see significant variation Findings presented from the Canadian made Alpha Particle X ray Spectrometer APXS on Curiosity s arm indicate that the wet environmental processes that produced clay at Yellowknife Bay did so without much change in the overall mix of chemical elements present The elemental composition of the outcrop Curiosity drilled into matches the composition of basalt For example it has basalt like proportions of silicon aluminum magnesium and iron Basalt is the most common rock type on Mars It is igneous but it is also thought to be the parent material for sedimentary rocks Curiosity has examined

    Original URL path: http://www.lpi.usra.edu/features/mars/curiosity/032513/ (2016-02-15)
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  • “Hot Spots” Ride a Merry-Go-Round on Jupiter
    an atmospheric probe that descended into a hot spot in 1995 This was the first and so far only in situ investigation of Jupiter s atmosphere Galileo s probe data and a handful of orbiter images hinted at the complex winds swirling around and through these hot spots and raised questions about whether they fundamentally were waves cyclones or something in between said Ashwin Vasavada a paper co author who is based at NASA s Jet Propulsion Laboratory in Pasadena California and who was a member of the Cassini imaging team during the Jupiter flyby Cassini s fantastic movies now show the entire life cycle and evolution of hot spots in great detail Because hot spots are breaks in the clouds they provide windows into a normally unseen layer of Jupiter s atmosphere possibly all the way down to the level where water clouds can form In pictures hot spots appear shadowy but because the deeper layers are warmer hot spots are very bright at the infrared wavelengths where heat is sensed in fact this is how they got their name One hypothesis is that hot spots occur when big drafts of air sink in the atmosphere and get heated or dried out in the process But the surprising regularity of hot spots has led some researchers to suspect there is an atmospheric wave involved Typically 8 to 10 hot spots line up roughly evenly spaced with dense white plumes of cloud in between This pattern could be explained by a wave that pushes cold air down breaking up any clouds and then carries warm air up causing the heavy cloud cover seen in the plumes Computer modeling has strengthened this line of reasoning From the Cassini movies the researchers mapped the winds in and around each hot spot and

    Original URL path: http://www.lpi.usra.edu/features/cassini/032513/ (2016-02-15)
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  • NASA-Supported Lunar Scientists Find New Link In Solar-System-Wide Impact Bombardment
    March issue of Nature Geoscience in an article entitled High Velocity Collisions from the Lunar Cataclysm Recorded in Asteroidal Meteorites With the aid of computer simulations the researchers determined that meteorites from Vesta recorded impacts by unusually high speed projectiles that are now long gone They deduced that this period of bombardment was related to a possible dramatic time in solar system history four billion years ago when gas giant planets like Jupiter and Saturn were migrating from their original orbits to where we see them today The team s findings support the theory that this repositioning of the gas giant planets destabilized portions of the asteroid belt and triggered a solar system wide bombardment of asteroids This event called the lunar cataclysm pulled many asteroids into orbits that collided with Earth and the Moon The research provides new constraints on the start and duration of the lunar cataclysm and it demonstrates that the cataclysm was an event that affected not only the inner solar system planets but asteroid belts as well The team s interpretation of the howardites and eucrites was augmented by recent close in observations of Vesta s surface by NASA s Dawn spacecraft In addition the team used the latest dynamical models of early main belt evolution to find out the likely source of these high velocity impactors and determined that the same projectiles hitting Vesta also had orbits that struck the Moon at high speeds It appears that the asteroidal meteorites show signs of the asteroid belt losing a lot of mass four billion years ago with the escaped mass beating up on both the surviving main belt asteroids and the Moon at high speeds says lead author Simone Marchi who has a joint appointment between two NLSI teams the Center for Lunar Origin and

    Original URL path: http://www.lpi.usra.edu/features/meteorites/032513/ (2016-02-15)
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