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| Risultati della ricerca nelle immagini - "Studies" |
017-The Moon from Clem-NearSide-PIA00302.jpg003 - The Near-Side of the Moon55 visiteAbout 50.000 Clem images were processed to produce the 4 orthographic views of the Moon. Images PIA00302, PIA00303, PIA00304 and PIA00305 show albedo variations (normalized brightness or reflectivity) of the surface at a wavelength of 750 nm (just longward of visible red). The Lunar Near-Side is a contrast between dark and light albedo surfaces that has been fancied as the "Man in the Moon". Lunar terrain types are still designated by their 17th century name and that is:
1. Maria (dark albedo features also known as basins) and
2. Terra (brighter albedo features also known as uplands or highlands).
The Maria constitutes about 16% while the Terra 84% of the Lunar Surface. The nearside is composed of about 30 percent maria. Extensive bright ray systems surround craters Copernicus (upper left center) and Tycho (near bottom).
Studies have shown that two major processes, impact and basaltic volcanism have shaped the major physical features of the Lunar Surface.
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32-MareHumorum.jpgMare Humorum61 visiteThis mosaic of three images, taken by the advanced Moon Imaging Experiment (AMIE) on board ESA's SMART-1 spacecraft, shows Mare Humorum on the Moon.
AMIE obtained the top frame on 1 January 2006, from a distance of 1087 kilometres from the surface, with a ground resolution of 98 metres per pixel. The remaining two frames were taken on 13 January 2006, from a distance of about 1069 (centre) and 1050 kilometres (bottom) from the surface, with a ground resolution of 97 and 95 metres per pixel, respectively.
The area shown in the top image is centred at a latitude of 40.2º South and longitude 25.9º West; the centre image is centred at a latitude of 40.2º South and longitude 27.3º West; the bottom image is centred at a latitude of 40.2º South and longitude 28.8º West.
Mare Humorum, or 'Sea of Moisture', is a small circular mare on the lunar nearside, about 825 kilometres across. The mountains surrounding it mark the edge of an old impact basin which has been flooded and filled by mare lavas. These lavas also extend past the basin rim in several places. In the upper right are several such flows which extend northwest into southern Oceanus Procellarum.
Mare Humorum was not sampled by the Apollo program, so its precise age could not been determined yet. However, geologic mapping indicates that its age is in between that of the Imbrium and the Nectaris basins, suggesting an age of about 3.9 thousand million years (with an uncertainty of 500 million years).
Humorum is filled with a thick layer of mare basalt, believed to exceed 3 kilometres in thickness at the centre of the basin. On the north edge of Mare Humorum is the large crater Gassendi, which was considered as a possible landing site for Apollo 17.
Mare Humorum is a scientifically interesting area because it allows the study of the relationships among lunar mare filling, mare basin tectonics, and global thermal evolution to the major mascon maria – regions of the moon's crust which contain a large amount of material denser than average for that area (Solomon, Head, 1980).
Past studies (Budney, Lucey) revealed that craters in the mare Humorum sometimes excavate highland material, allowing to estimate the thickness from below the mare cover. Thanks to this, it was also possible to determine that the ‘multiring’ structure of the Humorum basin has a diameter of 425 kilometres (results based on the US Clementine global topography data).
In general, the chronology of lunar volcanism is based on the analysis of landing site samples from the Apollo and Luna missions, from the study of the relationship between the stratigraphy (layering of deposits) in different regions, and from the analysis of lunar craters – how they degraded over time and how their distribution in number and size varies over the Moon’s surface. From crater statistics, in the year 2000 Hiesinger and colleagues found that in Humorum there was a peak of eruptions at about 3.3-3.5 thousand million years ago.
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8-Venus_from_Venus_Express-VIRTIS_COB05_vis_397_b.jpgVenus, from Venus Express (natural colors)77 visiteCaption ESA originale:"Views of the Southern Hemisphere of Venus in visible and ultraviolet light show interesting atmospheric stripe-like structures.
Spotted for the first time by Mariner 10 in the 1970s, they may be due to the presence of dust and aerosols in the atmosphere, but their true nature is still unexplained. "Venus Express has the tools to investigate these structures in detail. Studies have already begun to dig into the properties of the complex wind fields on Venus, to understand the atmospheric dynamics on local and global scales".
Venus Express also made use for the first time ever from orbit of the so-called 'infrared windows' present in the atmosphere of Venus – if observed at certain wavelengths, it is possible to detect thermal radiation leaking from the deepest atmospheric layers, revealing what lies beneath the dense cloud curtain situated at about 60 Km altitude".
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ALANBEAN-CORETUBE.jpgCore-Tube103 visiteDalla Galleria Pittorica dell'Astronauta Alan Laverne Bean: un Omaggio alla Luna ed a quei pochi che ebbero il coraggio, la fortuna ed il privilegio di camminarci sopra.
Ma lasciamo che sia "Alan" a raccontarci questa storia: la "Sua Storia"...
"...When my book, "Apollo, An Eyewitness Account", was published in October of 1998, I felt an overall sense of satisfaction. I was, in fact, preserving some of my special memories of the Apollo Program. This was the reason I resigned from NASA to become an artist.
I was moving right along but I noticed my goals for the future were even more ambitious. I wanted to paint the Moon more beautifully than I had done so far, as colorful as it could be painted, and still look like the Moon to me, a worthy but elusive goal.
I stopped painting commissions and began painting several series of studies to explore and develop new color techniques and combinations. This intense and dedicated effort consumed me for the better part of a year with the resulting changes first coming to full fruition in this painting.
Sometimes when I look at this painting I wonder if the changes were all that much. I question if anyone other than me can see them or even care? I don't know. Was it worth the time? I hope so...".
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APOLLO 16 AS 16-122-19580.jpgAS 16-122-19580 - King Crater52 visiteThis vertical view of the crater King on the Lunar Far-Side was taken with the Apollo 16 Hasselblad camera. King, approx. 75 Km in diameter and 4 Km deep, is one of the most interesting features on the Far-Side. It is a superb example of a youthful, large crater. It attracted much attention and was the object of numerous scientific studies (Young, Brennan and Wolfe, 1972).
King is the freshest crater on the Far-Side in its size range. Among its many interesting features are:
1) a unique lobster-claw-like central peak;
2) a flat poollike area of dark material on the North rim believed to have once been molten;
3) a very-well-developed field of fine ejecta extending outward for approx. two crater diameters, and
4) a massive landslide on the South-East rim (see arrow).
In this view the Southern part of the central peak has a distinctly ropey appearance and is segmented parallel to the terraces of the adjacent crater wall. The low Sun illumination enhances the fine texture of King's ejecta. Northeast of King the ejecta mantles an old large crater and in the southwest corner of the picture it mantles a relatively smooth terra unit. The slightly raised plateau on which the crater is situated may be part of the ring of an old basin.
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Abell-901_and_902-PM.jpgAbell 901 and 902 Supercluster53 visiteAstronomers are using NASA's Hubble Space Telescope to dissect one of the largest structures in the universe as part of a quest to understand the violent lives of galaxies. Hubble is providing indirect evidence of unseen dark matter tugging on galaxies in the crowded, rough-and-tumble environment of a massive supercluster of hundreds of galaxies.
Dark matter is an invisible form of matter that accounts for most of the universe's mass. Hubble's Advanced Camera for Surveys has mapped the invisible dark matter scaffolding of the supercluster Abell 901/902, as well as the detailed structure of individual galaxies embedded in it.
The images are part of the Space Telescope Abell 901/902 Galaxy Evolution Survey (STAGES), which covers one of the largest patches of sky ever observed by the Hubble telescope. The area surveyed is so wide that it took 80 Hubble images to cover the entire STAGES field. The new work is led by Meghan Gray of the University of Nottingham in the United Kingdom and Catherine Heymans of the University of British Columbia in Vancouver, along with an international team of scientists.
The Hubble study pinpointed four main areas in the supercluster where dark matter has pooled into dense clumps, totaling 100 trillion times the Sun's mass. These areas match the location of hundreds of old galaxies that have experienced a violent history in their passage from the outskirts of the supercluster into these dense regions. These galaxies make up four separate galaxy clusters.
"Thanks to Hubble's Advanced Camera for Surveys, we are detecting for the first time the irregular clumps of dark matter in this supercluster," Heymans said. "We can even see an extension of the dark matter toward a very hot group of galaxies that are emitting X-rays as they fall into the densest cluster core."
The dark matter map was constructed by measuring the distorted shapes of over 60,000 faraway galaxies. To reach Earth, the galaxies' light traveled through the dark matter that surrounds the supercluster galaxies and was bent by the massive gravitational field. Heymans used the observed, subtle distortion of the galaxies' shapes to reconstruct the dark matter distribution in the supercluster using a method called weak gravitational lensing. The dark matter map is 2.5 times sharper than a previous ground-based survey of the supercluster.
"The new map of the underlying dark matter in the supercluster is one key piece of this puzzle," Gray explained. "At the same time we're looking in detail at the galaxies themselves." The survey's broader goal is to understand how galaxies are influenced by the environment in which they live.
On Earth, the pace of quiet country life is vastly different from the hustle of the big city. In the same way, galaxies living lonely isolated lives look very different from those found in the most crowded regions of the universe, like a supercluster. "We've known for a long time that galaxies in crowded environments tend to be older, redder, and rounder than those in the field," Gray said. "Galaxies are continually drawn into larger and larger groups and clusters by the inevitable force of gravity as the universe evolves."
In such busy environments galaxies are subject to a life of violence: high-speed collisions with other galaxies; the stripping away of gas, the fuel supply they use to form new stars; and distortion due to the strong gravitational pull of the underlying invisible dark matter. "Any or all of these effects may play a role in the transformation of galaxies, which is what we're trying to determine," Gray said.
The STAGES survey's simultaneous focus on both the big picture and the details can be likened to studying a big city. "It's as if we're trying to learn everything we can about New York City and New Yorkers," Gray explained. "We're examining large-scale features, like mapping the roads, counting skyscrapers, monitoring traffic. At the same time we're also studying the residents to figure out how the lifestyles of people living downtown differ from those out in the suburbs. But in our case the city is a supercluster, the roads are dark matter, and the people are galaxies."
Further results by other team members support this view. "In the STAGES supercluster we clearly see that transformations are happening in the outskirts of the supercluster, where galaxies are still moving relatively slowly and first feel the influence of the cluster environment," said Christian Wolf, an Advanced Research Fellow at the University of Oxford in the U.K.
Assistant professor Shardha Jogee and graduate student Amanda Heiderman, both of the University of Texas in Austin, concur. "We see more collisions between galaxies in the regions toward which the galaxies are flowing than in the centers of the clusters," Jogee said. "By the time they reach the center, they are moving too fast to collide and merge, but in the outskirts their pace is more leisurely, and they still have time to interact."
The STAGES team also finds that the outer parts of the clusters are where star formation in the galaxies is slowly switching off and where the supermassive black holes at the hearts of the galaxies are most active.
Added Heiderman: "The galaxies at the centers of the clusters may have been there for a long time and have probably finished their transformation. They are now old, round, red, and dead."
The team plans more studies to understand how the supercluster environment is responsible for producing these changes.
Abell 901/902 resides 2.6 billion light-years from Earth and measures more than 16 million light-years across.
MareKromium
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AlienWorld-PIA09228.jpgTwin Suns' Sunset53 visiteOur solitary sunsets here on Earth might not be all that common in the grand scheme of things. New observations from NASA's Spitzer Space Telescope have revealed that mature planetary systems -- dusty disks of asteroids, comets and possibly planets -- are more frequent around close-knit twin, or binary, stars than single stars like our sun. That means sunsets like the one portrayed in this artist's photo concept, and more famously in the movie "Star Wars," might be quite commonplace in the universe.
Binary and multiple-star systems are about twice as abundant as single-star systems in our galaxy, and, in theory, other galaxies. In a typical binary system, two stars of roughly similar masses twirl around each other like pair-figure skaters. In some systems, the two stars are very far apart and barely interact with each other. In other cases, the stellar twins are intricately linked, whipping around each other quickly due to the force of gravity.
Astronomers have discovered dozens of planets that orbit around a single member of a very wide stellar duo. Sunsets from these worlds would look like our own, and the second sun would just look like a bright star in the night sky.
But do planets exist in the tighter systems, where two suns would dip below a planet's horizon one by one? Unveiling planets in these systems is tricky, so astronomers used Spitzer to look for disks of swirling planetary debris instead. These disks are made of asteroids, comets and possibly planets. The rocky material in them bangs together and kicks up dust that Spitzer's infrared eyes can see. Our own solar system is swaddled in a similar type of disk.
Surprisingly, Spitzer found more debris disks around the tightest binaries it studied (about 20 stars) than in a comparable sample of single stars. About 60 percent of the tight binaries had disks, while the single stars only had about 20 percent. These snug binary systems are as close or closer than just three times the distance between Earth and the sun. And the disks in these systems were found to circumnavigate both members of the star pair, rather than just one.
Though follow-up studies are needed, the results could mean that planet formation is more common around extra-tight binary stars than single stars. Since these types of systems would experience double sunsets, the artistic view portrayed here might not be fiction.
The original sunset photo used in this artist's concept was taken by Robert Hurt of the Spitzer Science Center at the California Institute of Technology, Pasadena, Calif.
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Cepheid-HST-2009-08-a-print.jpgRefined Hubble Constant narrows possible explanations for Dark Energy54 visiteWhatever Dark Energy is, explanations for it have less wiggle room following a Hubble Space Telescope observation that has refined the measurement of the Universe's present Expansion Rate to a precision where the error is smaller than 5%. The new value for the Expansion Rate, known as the "Hubble Constant", or "H0" (after Edwin Hubble who first measured the expansion of the universe nearly a century ago), is 74,2 Km-per-second-per-megaparsec (with an error margin of ± 3,6).
The results agree closely with an earlier measurement gleaned from Hubble of 72 ± 8 km/sec/megaparsec, but are now more than twice as precise.
The Hubble measurement, conducted by the SHOES (Supernova H0 for the Equation of State) Team and led by Adam Riess, of the Space Telescope Science Institute and the Johns Hopkins University, uses a number of refinements to streamline and strengthen the construction of a cosmic "Distance Ladder", a Billion LY in length, that astronomers use to determine the Universe's Expansion Rate.
Hubble observations of pulsating stars called "Cepheid Variables" in a nearby cosmic mile marker, the galaxy NGC 4258, and in the host galaxies of recent supernovae, directly link these distance indicators. The use of Hubble to bridge these rungs in the ladder eliminated the systematic errors that are almost unavoidably introduced by comparing measurements from different telescopes.
Riess explains the new technique: "It's like measuring a building with a long tape measure instead of moving a yard stick end over end. You avoid compounding the little errors you make every time you move the yardstick. The higher the building, the greater the error".
Lucas Macri, professor of physics and astronomy at Texas A&M, and a significant contributor to the results, said, "Cepheids are the backbone of the distance ladder because their pulsation periods, which are easily observed, correlate directly with their luminosities. Another refinement of our ladder is the fact that we have observed the Cepheids in the Near-InfraRed parts of the electromagnetic spectrum where these variable stars are better distance indicators than at optical wavelengths."
This new, more precise value of the Hubble Constant was used to test and constrain the properties of Dark Energy, the form of energy that produces a repulsive force in space, which is causing the expansion rate of the Universe to accelerate.
By bracketing the expansion history of the universe between today and when the universe was only approx. 380.000 years old, the astronomers were able to place limits on the nature of the Dark Energy that is causing the expansion to speed up.
(The measurement for the far, early universe is derived from fluctuations in the Cosmic Microwave Background (---> Radiazione di Fondo), as resolved by NASA's Wilkinson Microwave Anisotropy Probe, WMAP, in 2003.)
Their result is consistent with the simplest interpretation of Dark Energy: that it is mathematically equivalent to Albert Einstein's hypothesized Cosmological Constant, introduced a century ago to push on the fabric of space and prevent the Universe from collapsing under the pull of gravity. (Einstein, however, removed the Constant once the expansion of the universe was discovered by Edwin Hubble.)
"If you put in a box all the ways that Dark Energy might differ from the Cosmological Constant, that box would now be 3 times smaller", says Riess. "That's progress, but we still have a long way to go to pin down the nature of Dark Energy".
Though the cosmological constant was conceived of long ago, observational evidence for Dark Energy didn't come along until 11 years ago, when two studies, one led by Riess and Brian Schmidt of Mount Stromlo Observatory, and the other by Saul Perlmutter of Lawrence Berkeley National Laboratory, discovered Dark Energy independently, in part with Hubble observations. Since then astronomers have been pursuing observations to better characterize Dark Energy.
Riess's approach to narrowing alternative explanations for Dark Energy — whether it is a static Cosmological Constant or a dynamical field (like the repulsive force that drove inflation after the Big Bang) — is to further refine measurements of the Universe's expansion history.
Before Hubble was launched in 1990, the estimates of the Hubble Constant varied by a factor of two. In the late 1990s the Hubble Space Telescope Key Project on the Extragalactic Distance Scale refined the value of the Hubble constant to an error of only about 10%. This was accomplished by observing Cepheid variables at optical wavelengths out to greater distances than obtained previously and comparing those to similar measurements from ground-based telescopes.
The SHOES team used Hubble's Near Infrared Camera and Multi-Object Spectrometer (NICMOS) and the Advanced Camera for Surveys (ACS) to observe 240 Cepheid variable stars across 7 galaxies. One of these galaxies was NGC 4258, whose distance was very accurately determined through observations with radio telescopes. The other 6 galaxies recently hosted Type Ia Supernovae that are reliable distance indicators for even farther measurements in the Universe.
Type Ia Supernovae all explode with nearly the same amount of energy and therefore have almost the same intrinsic brightness.
By observing Cepheids with very similar properties at Near-InfraRed wavelengths in all 7 galaxies and using the same telescope and instrument, the team was able to more precisely calibrate the luminosity of Supernovae.
With Hubble's powerful capabilities, the team was able to sidestep some of the shakiest rungs along the previous Distance Ladder involving uncertainties in the behavior of Cepheids. Riess would eventually like to see the Hubble constant refined to a value with an error of no more than 1%, to put even tighter constraints on solutions to Dark Energy.MareKromium
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Craters-Victoria_Crater-PIA12167.jpgVictoria Crater (Natural Colors; credits: Lunexit)56 visiteThis image of Victoria Crater in the Meridiani Planum Region of Mars was taken by the High Resolution Imaging Science Experiment (HiRISE) camera on NASA's Mars Reconnaissance Orbiter at more of a sideways angle than earlier orbital images of this feature.
The camera pointing was 22° East of straight down, yielding a view comparable to looking at the landscape out an airplane window. East is at the top. The most interesting exposures of geological strata are in the steep walls of the Crater, difficult to see from straight overhead.
Especially prominent in this oblique view is a bright band near the top of the Crater wall.
Earlier HiRISE images of Victoria Crater supported the exploration of this Crater by NASA's Opportunity Rover and contributed to joint scientific studies. Opportunity explored the Rim and interior of this 800-meter-wide (about 0,5-mile-wide) Crater from September 2006 through August 2008.
The Rover's on-site investigations indicated that the bright band near the top of the Crater wall was formed by diagenesis (chemical and physical changes in sediments after deposition). The bright band separates bedrock from the material displaced by the impact that dug the Crater.
This view is a cutout from a HiRISE exposure taken on July 18, 2009. Some of Opportunity's Tracks are still visible to the North of the Crater (left side of this cutout).
Full-frame images from this HiRISE observation, catalogued as ESP_013954_1780, are at http://hirise.lpl.arizona.edu/ESP_013954_1780.
The full-frame image is centered at 2,1° South Latitude and 354,5° East Longitude. It was taken at 2:31 p.m. Local Mars Time. The scene is illuminated from the West with the Sun about 49° above the Local Horizon (therefore the S.I.A. was about 41°).MareKromium
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Dark_Matter.jpgBright Universe, Dark Matter54 visiteAn international team of astronomers using NASA's Hubble Space Telescope has created a three-dimensional map that provides the first direct look at the large-scale distribution of dark matter in the universe.
Dark matter is an invisible form of matter that accounts for most of the universe's mass.
The map provides the best evidence yet that normal matter, largely in the form of galaxies, accumulates along the densest concentrations of dark matter. The map reveals a loose network of filaments that grew over time and intersect in massive structures at the locations of clusters of galaxies.
The map stretches halfway back to the beginning of the universe and shows how dark matter has grown increasingly "clumpy" as it collapses under gravity.
This milestone takes astronomers from inference to direct observation of dark matter's influence in the universe. Previous studies of dark matter are based largely on numerical simulations of the expected evolution of large-scale structure. This evolution is driven by the gravitational attraction of dark matter.
Mapping dark matter's distribution in space and time is fundamental to understanding how galaxies grew and clustered over billions of years. Tracing the growth of clustering in the dark matter may eventually also shed light on dark energy, a repulsive form of gravity that influences how dark matter clumps.
The new maps of dark matter and galaxies will provide critical observational underpinnings to future theories for how structure formed in the evolving universe under the relentless pull of gravity. Theories suggest the universe transitioned from a smooth distribution of matter into a sponge-like structure of long filaments.
The research results appeared online today in the journal Nature and were presented at the 209th meeting of the American Astronomical Society in Seattle, Wash., by Richard Massey for the dark matter and Nick Scoville for the galaxies. Both researchers are from the California Institute of Technology, Pasadena, Calif.
"It's reassuring how well our map confirms the standard theories for structure formation." said Massey. He calls dark matter the "scaffolding" inside of which stars and galaxies have been assembled over billions of years.
Researchers created the map using Hubble's largest survey of the universe, the Cosmic Evolution Survey ("COSMOS") with an international team of 70 astronomers led by Scoville. The COSMOS survey covers a sufficiently wide area of sky – nine times the area of the Earth's Moon. This allows for the large-scale filamentary structure of dark matter to be evident. To add 3-D distance information, the Hubble observations were combined with multicolor data from powerful ground-based telescopes. "The 3-D information is vital to studying the evolution of the structures over cosmic time," said Jason Rhodes, a collaborator in the study at the Jet Propulsion Laboratory in Pasadena, Calif.
The dark matter map was constructed by measuring the shapes of half a million faraway galaxies. To reach us, the galaxies' light has traveled through intervening dark matter. The dark matter deflected the light slightly as it traveled through space. Researchers used the observed, subtle distortion of the galaxies' shapes to reconstruct the distribution of intervening mass along Hubble's line of sight — a method called weak gravitational lensing. This effect is analogous to deducing the rippling pattern in a glass shower door by measuring how light from behind it is distorted as it passes through the glass.
"Although this technique has been employed previously, the depth of the COSMOS image and its superior resolution enables a more precise and detailed map, covering a large enough area to see the extended filamentary structures," said co-investigator Richard Ellis of the California Institute of Technology.
For astronomers, the challenge of mapping the universe has been similar to mapping a city from nighttime aerial snapshots showing only streetlights. Dark matter is invisible, so only the luminous galaxies can be seen directly. The new images are equivalent to seeing a city, its suburbs and country roads — in daylight, for the first time. Major arteries and intersections become evident, and a variety of neighborhoods are revealed.
A separate COSMOS team led by Scoville presented images of the large scale galactic structures in the same area with the dark matter. Galaxies appear in visible light seen with Hubble and in ground-based Subaru telescope images by Yoshiaku Taniguchi and colleagues. The hot gas in the densest galaxy clusters was imaged in X-rays by Gunther Hasinger and colleagues using the European Space Agency's XMM-Newton telescope.
Galaxy structures inside the dark matter scaffolding show clusters of galaxies in the process of assembly. These structures can be traced over more than 80 million light-years in the COSMOS survey – approximately five times the extent of the nearby Virgo galaxy cluster. In the densest early universe structures, many galaxies already have old stellar populations, implying that these galaxies formed first and accumulated the greatest masses in a bottom-up assembly process where smaller galaxies merge to make bigger galaxies — like tributaries converging to form a large river.
The COSMOS survey shows that galaxies with on-going star formation, even to the present epoch, dwell in less populated voids and dark matter filaments. "It is remarkable how the environment on the enormous cosmic scales seen in the dark matter structures can influence the properties of individual stars and galaxies — both the maturity of the stellar populations and the progressive 'downsizing' of star formation to smaller galaxies is clearly dependent on the dark matter environment," said Scoville.
"The comparison is of fundamental importance," said Massey. "Almost all current scientific knowledge concerns only baryonic matter. Now that we have begun to map out where dark matter is, the next challenge is to determine what it is, and specifically its relationship to normal matter."
In making the COSMOS survey, Hubble photographed 575 slightly overlapping views of the universe using the Advanced Camera for Surveys' (ACS) Wide Field Camera onboard Hubble. It took nearly 1,000 hours of observations. Thousands of galaxies' spectra were obtained by using the European Southern Observatory's Very Large Telescope in Chile, and the Subaru telescope in Hawaii. The distances to the galaxies were accurately determined through their spectral redshifts. The distribution of the normal matter was partly determined with the European Space Agency's XMM-Newton telescope.
MareKromium
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ESP_013954_1780_RED_abrowse-02.jpgVictoria Crater (EDM - Natural Colors; credits: Lunexit)52 visiteVictoria Crater was explored by Opportunity Rover for more than a Mars year; HiRISE images have supported surface exploration and contributed to joint scientific studies.
HiRISE stereo data were used to measure slopes and help select safe paths for the intrepid Rover. The most interesting exposures of geologic strata are in the steep walls of the Crater, difficult to image from the overhead perspective of orbiting spacecraft like MRO. However, MRO can point to the sides, and did so in this case to get a better view of layers in the West-facing and sunlit slopes of the Crater.
Especially prominent is a bright band near the top of the Crater Wall, interpreted by some MER scientists as having formed by diagenesis (chemical and physical changes in sediments after deposition). This bright band separates the bedrock from the impact ejecta deposits of Victoria Crater.MareKromium
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ESP_023024_1685_RED_abrowse-PCF-LXTT-01.jpgUplifted Rocks in Crater Center (EDM - Absolute Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)172 visiteCaption NASA:"This EDM reveals varied colors, suggesting that a range of rock types are present. Studies of these rocks from far below the Surface help us to understand ancient Mars as well as the processes that have altered the rocks after they formed and were buried".MareKromium
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