segunda-feira, 28 de setembro de 2015
sexta-feira, 25 de setembro de 2015
Of the spectacular new images sent back of Pluto from NASA's New Horizons July 14 flyby of the icy dwarf planet, perhaps most stunning is a color mosaic made up of the high-resolution images transmitted back to date.
It shows a nearly full globe, allowing viewers to zoom in on features across the surface, from dark, cratered terrains and ice mountains to the smooth, frozen plains marking the now-familiar "heart" of Pluto, dubbed Sputnik Planum, to the strangely ridged terrain that so far defies explanation.
"It's a unique and perplexing landscape stretching over hundreds of miles," William McKinnon, New Horizons Geology, Geophysics and Imaging (GGI) team deputy lead, said in a NASA release describing the ridged terrain.
"It looks more like tree bark or dragon scales than geology," he said. "This'll really take time to figure out. Maybe it's some combination of internal tectonic forces and ice sublimation driven by Pluto's faint sunlight."
A new high-resolution view reveals unusual linear ridges stretching across hundreds of miles, along with deep canyons and smooth plains blanketed by sharp shadows from the strange-looking ridges:
The near-global map, in cylindrical projection, is not yet complete, but it adds another powerful tool for scientists to begin understanding the structure and evolution of Pluto's intriguing surface. An equally stunning, zoomable nearly-full globe view shows the planet as it might appear to an astronaut on final approach.
"Pluto's surface colors were enhanced in this (cylindrical projection) view to reveal subtle details in a rainbow of pale blues, yellows, oranges and deep reds," said John Spencer, a GGI deputy lead. "Many landforms have their own distinct colors, telling a wonderfully complex geological and climatological story that we have only just begun to decode."
Along with the new pictures, the New Horizons team provided a map showing the distribution of methane ice across the part of Pluto's surface that has been seen to date. Sputnik Planum, a bright, smooth plain, shows relatively high concentrations as do brighter crater rims and ridges. No methane shows up inside deep craters or across the dwarf planet's darker regions.
Scientists do not yet know whether the methane somehow favors the brighter areas or if the ice makes the regions bright to begin with.
"It's like the classic chicken-or-egg problem," Will Grundy, New Horizons surface composition team lead, said in the NASA release. "We're unsure why this is so, but the cool thing is that New Horizons has the ability to make exquisite compositional maps across the surface of Pluto, and that'll be crucial to resolving how enigmatic Pluto works."
Said Alan Stern, the New Horizons principal investigator: "I wish Pluto's discoverer Clyde Tombaugh had lived to see this day."
New Horizons flew past Pluto on July 14 and as of Thursday was 72 days and more than 53 million miles beyond the dwarf planet.
Because of the vast distances involved -- more than 3 billion miles -- the size of the spacecraft's antenna and the power of its transmitters, it will take more than a year and a half for New Horizons to beam back all of its stored imagery and data. The science team is releasing selected photos every week or so as new images come in.
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quinta-feira, 24 de setembro de 2015
Two Mars Spacecraft Celebrate One Year in Martian Orbit
NASA’s Mars Atmosphere and Volatile EvolutioN (MAVEN) and India’s Mars Orbiter Mission (MOM) celebrate one year in Martian orbit this week. MAVEN started its journey to Mars on Nov. 18, 2013, and entered Mars’ orbit on Sept. 21, 2014. The Indian probe, which was launched earlier, on Nov. 5, 2013, arrived at Mars three days after the U.S. spacecraft, on Sept. 24, 2014.
“The success of the mission so far is a direct result of the incredibly hard work of everybody who is working and has worked on MAVEN. This one year at Mars reflects the tremendous efforts over the preceding dozen years,” said Bruce Jakosky, MAVEN’s principal investigator from the University of Colorado’s Laboratory for Atmospheric and Space Physics in Boulder.
MAVEN began its primary science mission on Nov. 16, 2014, and is the first spacecraft dedicated to understanding Mars’ upper atmosphere. The goal of the mission is to determine the role that loss of atmospheric gas to space played in changing the Martian climate through time. MAVEN is studying the entire region from the top of the upper atmosphere all the way down to the lower atmosphere so that the connections between these regions can be understood.
During the first year in Martian orbit, MAVEN has carried out ten months of observations during its primary mission and four deep-dip campaigns.
“We still have two months to go in our primary mission, and then we begin our extended mission,” Jakosky said. “We’re obtaining an incredibly rich data set that is on track to answer the questions we originally posed for MAVEN and that will serve the planetary science community for a long time to come.”
“The team has done a fantastic job of adapting to spacecraft operations in the Martian environment,” said Richard Burns, MAVEN project manager at NASA’s Goddard Space Flight Center in Greenbelt, Maryland. “All systems on MAVEN remain in excellent working condition.”
The MOM spacecraft, sent by the Indian Space Research Organisation (ISRO) has also completed a successful year at Mars. The probe has already delivered a set of global views of Mars and images of the Martian surface. MOM's methane sensors have successfully studied Mars' albedo, the reflectivity of the planet's surface.
|India’s Mars Orbiter Mission (MOM). Credit: ISRO|
The mission objectives are to showcase India's rocket launch systems, spacecraft building and operations capabilities. The primary objective is to develop the technologies required for designing, planning, management and operations of an interplanetary mission. MOM’s secondary objective is to explore Mars' surface features, morphology, mineralogy and Martian atmosphere using indigenous scientific instruments.
ISRO extended the MOM mission by an additional six months in March 2015 as the spacecraft has 37 kg (82 lbs.) of propellant remaining and all five of its scientific instruments are working properly. The orbiter can reportedly continue orbiting Mars for several years with its remaining propellant.
"Mars (mission) is expected to last for many years now, because it has gone through solar conjunction also; so we don't see much of a problem," ISRO Chairman AS Kiran Kumar said.
"We had planned it only for six months. Then we were not expecting so much fuel to remain after we completed our insertion activity… all other subsystems are working fine and so far we have not had any failures," he added.
ISRO will mark the first anniversary of Mars Orbit Insertion by releasing an atlas containing photos taken by the color camera on board the spacecraft. On Nov. 5, it would also release a book tracing the journey of the space agency.
"Currently, on September 24, we will be releasing one of the atlases… then, on November 5, we are bringing out a book, 'Fishing hamlet to Mars'," Kumar revealed.
Thanks to the success of the MOM mission, ISRO has become the fourth space agency to reach Mars, after the Soviet space program, NASA, and the European Space Agency (ESA). India is the first Asian nation to reach Mars orbit, and the first nation in the world to do so in its first attempt.
NASA WEB ·A galactic maelstrom-This new NASA/ESA Hubble Space Telescope shows Messier 96, a spiral galaxy just over 35 million light-years away in the constellation of Leo (The Lion). It is of about the same mass and size as the Milky Way. It was first discovered by astronomer Pierre Méchain in 1781, and added to Charles Messier’s famous catalogue of astronomical objects just four days later.
A galactic maelstromCredit:
NASA WEB ·A cosmic couple-Here we see the spectacular cosmic pairing of the star Hen 2-427 — more commonly known as WR 124 — and the nebula M1-67 which surrounds it. Both objects, captured here by the NASA/ESA Hubble Space Telescope are found in the constellation of Sagittarius and lie 15 000 light-years away.
A cosmic coupleCredit:
segunda-feira, 21 de setembro de 2015
quinta-feira, 10 de setembro de 2015
NASA WEB · Ceres' Bright Spots Seen in Striking New Detail The brightest spots on the dwarf planet Ceres gleam with mystery in new views delivered by NASA's Dawn spacecraft. These closest-yet views of Occator crater, with a resolution of 450 feet (140 meters) per pixel, give scientists a deeper perspective on these very unusual features.
|Ceres' Bright Spots Seen in Striking New Detail|
The brightest spots on the dwarf planet Ceres gleam with mystery in new views delivered by NASA's Dawn spacecraft. These closest-yet views of Occator crater, with a resolution of 450 feet (140 meters) per pixel, give scientists a deeper perspective on these very unusual features.
The new up-close view of Occator crater from Dawn's current vantage point reveals better-defined shapes of the brightest, central spot and features on the crater floor. Because these spots are so much brighter than the rest of Ceres' surface, the Dawn team combined two different images into a single composite view -- one properly exposed for the bright spots, and one for the surrounding surface.
Scientists also have produced animations that provide a virtual fly-around of the crater, including a colorful topographic map.
The individual animations are available at:
Dawn scientists note the rim of Occator crater is almost vertical in some places, where it rises steeply for 1 mile (nearly 2 kilometers).
Views from Dawn's current orbit, taken at an altitude of 915 miles (1,470 kilometers), have about three times better resolution than the images the spacecraft delivered from its previous orbit in June, and nearly 10 times better than in the spacecraft's first orbit at Ceres in April and May.
"Dawn has transformed what was so recently a few bright dots into a complex and beautiful, gleaming landscape," said Marc Rayman, Dawn's chief engineer and mission director based at NASA's Jet Propulsion Laboratory, Pasadena, California. "Soon, the scientific analysis will reveal the geological and chemical nature of this mysterious and mesmerizing extraterrestrial scenery."
The spacecraft has already completed two 11-day cycles of mapping the surface of Ceres from its current altitude, and began the third on Sept. 9. Dawn will map all of Ceres six times over the next two months. Each cycle consists of 14 orbits. By imaging Ceres at a slightly different angle in each mapping cycle, Dawn scientists will be able to assemble stereo views and construct 3-D maps.
Dawn is the first mission to visit a dwarf planet, and the first to orbit two distinct solar system targets. It orbited protoplanet Vesta for 14 months in 2011 and 2012, and arrived at Ceres on March 6, 2015.
Dawn's mission is managed by JPL for NASA's Science Mission Directorate in Washington. Dawn is a project of the directorate's Discovery Program, managed by NASA's Marshall Space Flight Center in Huntsville, Alabama. UCLA is responsible for overall Dawn mission science. Orbital ATK Inc., in Dulles, Virginia, designed and built the spacecraft. The German Aerospace Center, Max Planck Institute for Solar System Research, Italian Space Agency and Italian National Astrophysical Institute are international partners on the mission team. For a complete list of mission participants, visit: