danielost Posted December 20, 2009 #251 Share Posted December 20, 2009 Eh? Dry ice is a solid. CO2 can be stored under pressure as a liquid -- that's what's in a CO2 fire extinguisher, or a CO2 cartridge (the difference being the location of the siphon; the fire extinguisher expels liquid CO2 which expands outside the cylinder with a huge heat capacity, cooling the fire whilst smothering it. The CO2 cartridge releases CO2 gas, which lowers the pressure inside the cylinder, which causes some of the liquid to evaporate. Thus, an interesting quality of the CO2 cartridge or cylinder; it maintains roughly equal pressure through the service life -- unless, of course, it is allowed to get too cold from all that internal expansion.) true dry ice is a solid but science considers it to be a liquid. because it lamnats instead of melt that is it evaperates. Link to comment Share on other sites More sharing options...
Perdition Posted December 20, 2009 #252 Share Posted December 20, 2009 true dry ice is a solid but science considers it to be a liquid. because it lamnats instead of melt that is it evaperates. What? No, science considers it a solid. It sublimates from solid to gas doesn't make it a liquid but a physical property of CO2. Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted May 23, 2010 Author #253 Share Posted May 23, 2010 Central Peak of Copernicus Crater 05.04.10 > Larger image LROC NAC close-up of light-toned bedrock exposed within the central structural uplift of Copernicus crater (~93-km diameter). NAC image M102293451, width is ~1.26 km and the outcrop is ~800 m wide. Credit: NASA/GSFC/Arizona State University Although large boulders are not rare on the Moon, in-place bedrock is a rarity. The Moon is so impact-battered that most bedrock surfaces (unless exposed on very high slopes) are covered with regolith, and thus bedrock rarely crops out. Bedrock exposures are scientifically important. Any given point on the lunar surface has been subjected to hundreds of millions of years of meteorite impacts; these impacts tend to redistribute rocks around the lunar surface. Rocks that you just pick up from the lunar surface therefore may not have originated from the point where you found it. Now, you might think from this fact that just sampling loose rocks might not be geologically informative, but loose rocks must have been transported or disrupted by a geologic or planetary process. These processes will overprint or alter a loose rock in some way, which will also provide incredibly useful information to the geoscientist. However, bedrock formed in the location in which it is found and therefore informs scientists about the local history. Craters are one of the places on the Moon that expose bedrock, often on the very high slopes. > Larger image Copernicus crater as seen by the LROC Wide Angle Camera. Arrow highlights the approximate position of today's Featured Image. (LROC WAC image M119985095ME; 75 m/pixel; image width is 90 km) Credit: NASA/GSFC/Arizona State University Today's LROC NAC image (M102293451) is a close up of the 93-km (58 miles) diameter Copernicus crater showing light-toned fractured bedrock exposed on the higher slopes on the central structural uplift. The bedrock observed in this NAC frame appears to be somewhat intact, and not a breccia (i.e., a rock consisting of a jumble of randomly oriented rock fragments). It is only slightly brecciated (or fragmented), which is consistent with the manner in which crater central peak rocks are uplifted and exposed. This location gives us a glimpse of bedrock that was protected beneath the surface until exposed by the Copernicus impact event and later landslides. Dark materials appear to fill fractures in this outcrop that may be highly shocked materials (e.g., impact melt or breccias) that were injected into the rock during the formation of Copernicus. > Larger image Anaglyph of the central peak of Copernicus crater. Requires the use of anaglyph glasses (with a red lens on the left and a blue lens on the right). Credit: NASA/GSFC/Arizona State University Spectral data from previous lunar orbital spacecraft suggested that the bulk of these light-toned rocks are consistent with troctolite (different from basalt and anorthosite that commonly occur on the lunar surface). A troctolite is a relatively uncommon igneous rock on Earth. Troctolites consist of almost equal parts of the minerals olivine and Ca-rich plagioclase and are found in some of the most ancient large subsurface igneous bodies on Earth. Such igneous bodies are thought to have formed so slowly over time that the crystals separated from the cooling liquid magma (somewhat like oil and water separating) and accumulated (either sinking to the bottom or floating to the surface) in the magma body. These magma bodies may be quite abundant beneath the lunar crust as suggested by spectral studies of crater central peaks and cosmochemical investigations of Apollo lunar samples (especially the regolith samples) as well as lunar meteorites. Related Links: βΊ Lunar Reconnaissance Orbiter Camera web site Source: NASA - LRO -Multimedia Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted May 23, 2010 Author #254 Share Posted May 23, 2010 Mare Frigoris Constellation Region of Interest 05.07.10 > Larger image The floor of a l.2-km diameter crater in the Mare Frigoris Constellation region of interest. Samples of this material could help us understand the complex geologic history of this region of the Moon. NAC image M126752534RE; scene width is 510 m. Credit: NASA/GSFC/Arizona State University Samples from small, relatively fresh craters like the one above may someday help us learn more about Mare Frigoris and its place in lunar geologic history. Mare Frigoris is located on the lunar nearside, to the north of the Imbrium and Serenitatis basins. Instead of being low in reflectance like typical mare basalts, its reflectance is intermediate between the mare to the south and highlands terrain to the north. This is likely due to a lower iron and titanium content than any of the sampled mare basalts, making it an intriguing end-member in the spectrum of lunar mare volcanism. > Larger image Clementine mosaic of the lunar nearside showing the approximate location (black arrow) of the Mare Frigoris region of interest. Credit: USGS Portions of Mare Frigoris, like the area near the Constellation region of interest outlined below, are so high in reflectance they're considered "light plains." Light plains can form in several different ways: through volcanism, with a composition even lower in iron and titanium; as the result of impact basin ejecta, which acts as a fluid, filling in topographic lows; or as ancient volcanic plains that were subsequently covered with a thin layer of highlands material ejected from nearby craters or basins which masks the true basaltic surface (a hidden, or "cryptomare"). Small craters like the one above excavate material from below the surface, and can help discern whether or not the material there is distinct in composition (as would be expected for cryptomare). Sampling this material would provide a definitive resolution to the geologic history of this fascinating region. > Larger image A WAC image showing the 40x40 km box centered on the Frigoris region of interest. Arrow indicates the location of the NAC image above. Image number M119673851ME. Credit: NASA/GSFC/Arizona State University Related Links: βΊ Lunar Reconnaissance Orbiter Camera web site Source: NASA - LRO -Multimedia Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted May 23, 2010 Author #255 Share Posted May 23, 2010 Van de Graaff Crater β The Lunar Figure 8 05.07.10 Image credit: NASA/Goddard No larger image available. Van de Graaff Crater, located on the lunar far side north of South Pole-Aitken Basin (172.08, -26.92), has an unusual figure 8 shape (~240 km x 140 km) that has long caught the eye of lunar scientists. Its shape suggests that it was formed by two separate impacts even though there is no crater wall separating its two halves. LOLA data indicate that the floor of the crater is relatively flat except for the presence of several smaller impact craters. Portions of its rim reach almost 1000 m above lunar mean elevation level, while its floor is near β 2100 m. Van de Graaff is a region of interest for robotic and human exploration of the Moon due to its location in a magnetically and geochemically anomalous region. The Moon does not have a global magnetic field like the Earth, thus the origin of its small, localized magnetic fields, such as the one near Van de Graaff, is of scientific interest. Van de Graaff and the surrounding region are also slightly enriched in the element thorium, an element found in lunar KREEP (potassium (K), rare earth elements (REE), and phosphorus (P)) terrain. Most of the Moonβs KREEP-rich materials are found on the lunar nearside, thus the presence of enhanced thorium in the Van de Graaff region is intriguing. Related Links: βΊ LOLA instrument Web site Source: NASA - LRO -Multimedia Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted May 23, 2010 Author #256 Share Posted May 23, 2010 In An Instant! 05.13.10 > Larger image Boulders and impact melt on the interior wall of a recent 5 km (3 mile) diameter crater. The rim of the crater is near the top of the image, downhill is towards the bottom of the image. Credit: NASA/GSFC/Arizona State University. Outside of the protective veil of the Earth's atmosphere, the Solar System is a dynamic, constantly changing environment. Nowhere is this more true than on the lunar surface. Asteroids and comets slam into the Moon at speeds greater than 16 km per second (10 miles per second) creating impact craters in a matter of seconds. So much energy is released in these impacts that the impactor is mostly vaporized and some of the target rock is melted. Rocks and soil are thrown out and form spectacular ejecta aprons. Rocks excavated from the deepest part of the crater typically land very near the rim, and material from the original surface is thrown out towards the edge of the ejecta blanket. Nature has provided a convenient look into the subsurface! > Larger image Bright and dark patterns show the distribution of ejecta of a 5 km diameter crater (8.0Β°N, 182.2Β°E), portion of LROC images M125733619L, R subsampled to 5 m/pixel. Credit: NASA/GSFC/Arizona State University The full resolution sub-image (top) focuses on the northeast wall (upper right) of the spectacular crater seen above. The low reflectance material is most likely impact melt that was thrown out during the impact. The streamers of impact melt (black materials) help scientists trace the path of ejecta taken during the cratering process. The floor of the crater is flat and dark: it is the remnant of impact melt that pooled in the bottom of the crater. The fact that these features are so well preserved is evidence that the crater formed recently in geologic terms. But how recent is recent? Over time smaller impacts will degrade these exquisite details and slowly this crater will fade into the background. Without samples, the only way we have of estimating ages of young craters is by counting the number of even smaller craters that have formed on their surfaces. The best way to date impact craters is to sample their impact melt - as the molten rock cooled and formed new minerals their radiometric clock was reset. Scientists can measure the ratio of parent atoms to their daughter products and very accurately determine the age of crystallization. Planetary scientists would very much like to obtain accurate age dates for many of these young craters to determine the rate of recent impacts on the Moon. Current impact rates determined for the Moon are applicable to the Earth! > Larger image Sometimes it's easy to lose a sense of scale when looking at high resolution images of the Moon - the diameter of this crater (5 km) is about the same as the distance from the steps of the Lincoln Memorial to the Capitol building. The solidified lake of impact melt in the bottom of the crater is 1200 meters (3937 ft) across! Meteor Crater (near Winslow, Arizona) is about the same size as this floor deposit. Aerial view of Meteor Crater, Arizona Credit: Photo by M. Wadhwa Studies of young impact craters by future astronaut explorers will provide key insights into a host of scientific questions, most especially about the timing of recent impacts in the Solar System and the nature of the cratering process here on Earth. Related Links: βΊ Lunar Reconnaissance Orbiter Camera web site Source: NASA - LRO -Multimedia Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted May 23, 2010 Author #257 Share Posted May 23, 2010 Central Peak of Bullialdus Crater 05.13.10 > Larger image Summit of the central peak of Bullialdus crater, a Constellation region of interest. LROC Narrow Angle Camera image M114098458LE, image is 500 m wide Credit: NASA/GSFC/Arizona State University Nearly every square inch of the Moon is affected by impact craters, from micron-sized pits to gargantuan impact basins (like the 1100 km diameter Imbrium basin, which you can see with your naked eyes on a clear night). Lunar craters have a dizzying array of sizes and morphologies; this is because the size and the morphology of a crater depends on the size (and to some extent, the speed) of the impacting bolide. > Larger image LROC Wide Angle Camera View of Bullialdus crater (60 km diameter). The approximate position of today's NAC featured image is highlighted with the white arrow. Credit: NASA/GSFC/Arizona State University The Moon is the best preserved and most accessible laboratory for understanding impact processes. Impacts are the most fundamental and important geologic process in the Solar System. On the Earth, which has been hit by impactors for over four billion years, erosion caused by wind and precipitation degrades impact craters, making them (relatively) hard to study. On the Moon, though, these craters are relatively well preserved. Complex craters are of particular interest. Complex craters have a well defined central peak and often a terraced rim; this central peak is brought up from great depths beneath the crater as the ground elastically rebounds after the shock and pressure of the bolide impact. These sorts of impacts happened on Earth, too - but the erosion caused by terrestrial weather removes all traces of their presence. On the Moon, though, complex impact structures are well-preserved, and the central peaks - which have brought up materials from great depth - offer us the easiest way to explore the composition of the Moon's lower crust and upper mantle, providing critical insights for planetary scientists trying to figure out how planets in this Solar System (and others, around other stars) form. Today's featured image shows the summit of the central peak of Bullialdus crater, an exploration region of interest located in the western part of Mare Nubium. Spectroscopic observations of Bullialdus using terrestrial telescopes showed that Bullialdus is compositionally distinct from the surrounding region. Later studies using Clementine multispectral data indicated that there are several rock types exposed on the floor of the crater. Lunar scientists who have studied Bullialdus proposed that the impact excavated mafic materials from great depth. Lunar scientists need to discover what these mafic materials are - are they some type of exotic mare basalts? Rare highlands non-mare volcanic rocks? We don't know, and we must find out to fully understand the Moon. The central peak of Bullialdus is about a kilometer high. Astronaut explorers will not only have to explore around the base, but probably also scale this small mountain to collect the diverse array of samples required to really answer this question. Related Links: βΊ Lunar Reconnaissance Orbiter Camera web site Source: NASA - LRO -Multimedia Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted May 23, 2010 Author #258 Share Posted May 23, 2010 Einstein and Einstein A: A Study in Crater Morphology 05.14.10 Image credit: NASA/Goddard > View larger image 5.14.2010 - Located on the western limb of the Moon, Einstein and Einstein A craters (16.3oN, 271.3oE ) are only visible to Earth-based observers during certain lunar lighting and orientation conditions. Einstein A is younger than Einstein, as indicated by the fact that it lies squarely in the middle of the floor of Einstein. When viewed in topographic data, these two craters reveal much about the relative age and shape of an impact crater. To understand further, let's first take a look at Einstein. Einstein is a fairly large crater that spans 198 km across. A crater's size alone however cannot reveal much about age. ΓEinstein's relative age can be determined by examining the frequency and distribution of impact craters overprinted on its rim and floor. Younger craters have had fewer impacts, which enables them to retain their original morphology. Einstein A reveals most of its original structure, including a raised rim and ejecta blanket, and is therefore a relatively young crater as compared to Einstein, whose original structure has been somewhat degraded over time by smaller impacts. The Einstein craters were named after famed physicist, philosopher, and scientist Albert Einstein (1879-1955). Related Links: βΊ LOLA instrument Web site Source: NASA - LRO -Multimedia Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted May 23, 2010 Author #259 Share Posted May 23, 2010 Hole In One! 05.19.10 > Larger image A house-sized boulder (10 m diameter) rolled down-hill, scoring a hole in one (~60 m diameter crater)! Portion of LROC NAC M122597190L, image width is 500 m across. Credit: NASA/GSFC/Arizona State University Golf-enthusiasts might look at today's image and say, "Wow, that boulder sure looks like a hole in one!" Boulders like this are incredible because we can determine where the boulder came from by back-tracking along the boulder trail. In fact, Apollo 17 Astronauts Schmitt and Cernan sampled a large boulder at Station 6, and because scientists were able to trace the original position of this boulder using its boulder trail, we can infer what the composition of the rocks up-slope may be. In this case, the boulder trail curves abruptly as the boulder approached its final resting place. What might have caused this boulder to deviate from its straight, downward course? You can see the boulder trail intersects a crater rim as the local slope was flattening out. As the boulder was slowing, it encountered a new steep slope on its right, thus turning it into the crater. Boulders fall from high elevations to lower ones because of gravity after being knocked loose by small impacts or moonquakes. Changes in slope can stop boulders; when a steep slope (like that of a crater wall) suddenly shallows, the boulder may not have enough inertia to continue moving. Inertia, or Newton's First Law of Motion, describes an object's resistance to change in velocity. So, a boulder will continue to move until something changes its speed or direction. > Larger image LROC WAC monochrome context image of complex crater Henry Frères (~42 km diameter), with a smaller, ~7 km diameter crater superposed (arrow). The floor of this smaller crater is highlighted in today's Featured Image (top). Image M117880746ME, scene is 55 km across. Credit: NASA/GSFC/Arizona State University Related Links: ⺠Lunar Reconnaissance Orbiter Camera web site Source: NASA - LRO -Multimedia Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted May 23, 2010 Author #260 Share Posted May 23, 2010 (edited) Reiner Gamma β A Lunar Swirl 05.20.10 Image credit: NASA/Goddard > View large color version (2 Mb) The Reiner Gamma region on the lunar nearside (7.5 N, 301.4 E) has an unusual surface feature called a βlunar swirl.β Visible in the Clementine 750-nm mosaic image shown here, it resembles a swirl of cream in a mug of hot chocolate. Lunar swirls have a higher albedo than the surrounding lunar surface. The formation of lunar swirls, especially the Reiner Gamma swirl, is a mystery. Although the Moon does not have a global magnetic field, localized magnetic fields have been observed in swirl regions. One idea is that the mini-magnetic fields have shielded the swirls from the solar wind, which can darken lunar soils over time. Two swirls on the lunar farside lie directly opposite nearside impact basins (Mare Imbrium and Mare Orientale), suggesting that their formation and that of the localized magnetic fields is related to the impacts that created the basins. Reiner Gamma does not have a corresponding impact basin on the farside. In addition, there appears to be no correlation between the Reiner Gamma swirl and its local topography. LOLA data show that the region is relatively flat. The contour interval in this image is 0.2 km. Related Links: βΊ LOLA instrument Web site Source: NASA - LRO -Multimedia Edited May 28, 2010 by Waspie_Dwarf Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted May 28, 2010 Author #261 Share Posted May 28, 2010 Splendors of Mare Smythii - Fresh Impact Craters 05.21.10 Interior of fresh impact crater in the Smythii region. Portion of image M126371530LE, scene width is 530 m Credit: NASA/Goddard/ASU > Larger image The featured image shows the interior of a fresh impact crater (approximately 300 m in diameter) in the Mare Smythii region. In the high-sun image above, it is hard to recognize topographic features because there are no shadows. The wider view below, paired with a lower-sun image of the same crater on the right, gives a sharper view of small scale features such as boulders. A wider view of the same fresh crater under high-sun (left, image M126371530LE, incidence angle of 21Β°) and lower sun image with illumination from the east (right, image M113392375LE, incidence angle of 50Β°) Credit: NASA/Goddard/ASU > Larger image The floor of this small crater looks like a basket of impact-melt covered rocks, containing secrets about the age of recent impacts and the processes that cause their fresh rays to fade. WAC context image of the Mare Smythii region (40x40 km box is centered on the region), which includes the eastern portion of crater Schubert C. Arrow indicates the location of the fresh crater above. Image M115753790CE Credit: NASA/Goddard/ASU > Larger image Mare Smythii, located on the eastern limb of the Moon, contains relatively young (1-2 billion years old) basaltic lavas. The western portion of the region encompasses the crater Schubert C, the floor of which is fractured, possibly due to intrusions of lava beneath its surface. Under high-sun, craters can take on an unusual appearance (left, M126371530LE). Under more typical illumination conditions, slumps of material and large boulders are revealed as the source of the high and low reflectance patterns (right, M113392375LE) Credit: NASA/Goddard/ASU > Larger image Mare Smythii contains many beautiful features, several of which are highlighted in high-sun images such as the one above. Source: NASA - LRO - News and Media Resources Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted May 28, 2010 Author #262 Share Posted May 28, 2010 Mare Tranquillitatis 05.28.10 Image credit: NASA/Goddard > View larger image Mare Tranquillitatis 5.28.2010 - The Sea of Tranquility has long captivated astronomers. Once thought to be an ocean on the Moon, its relatively smooth fields of basaltic lavas and equatorial position made it an ideal location for the first manned lunar landing. On July 20, 1969 Neil Armstrong and Buzz Aldrin left the first human footprints on the Moon near the southwestern shores of Mare Tranquillitatis. Mare Tranquillitatis (approximately 873 km in diameter) lies in the Tranquillitatis basin (centered on 0.68 N, 23.43 E; extending, roughly, from 20.4 N-4.4 S, 15.0-45.9 E). This basin is thought to have been formed as a result of a very large impact in the Moon's early history, likely more than 3.9 million years ago. The crater was then flooded with mare basalts, making it appear dark when viewed from Earth, and making it smooth and relatively flat, as seen in LOLA data. There is only a little over a 500 m elevation difference between the highest and lowest points within the mare, excluding overprinted craters. The mare has an irregular margin because several basins, including Serenitatis and Nectaris, intersect in this region. See if you can find other features surrounding Mare Tranquillitatis on a map of the Moon. For other information and exploration news, check out one of Science@NASA's Apollo Chronicles featuring Neil Armstrong and Buzz Aldrin's experience in the Sea of Tranquility, the featured LROC images of a wrinkle ridge in the Mare Tranquillitatis Constellation Region of Interest, and the Apollo landing sites. Related Links: βΊ LOLA instrument Web site Source: NASA - LRO -Multimedia Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted June 4, 2010 Author #263 Share Posted June 4, 2010 Humboldtianum Basin 06.04.10 Image credit: NASA/Goddard No larger image available Humboldtianum Basin 06.04.2010 - Located along the northeastern limb of the Moon (centered at approximately 56.8 N, 81.5 E), Humboldtianum Basin is a region of interest for NASA. LOLA data show that the 650 Km diameter basin is more than 4.5 km deep. Humboldtianum Basin is estimated to have formed during the Moonβs Nectarian Period, approximately 3.92-3.85 billion years ago. Many other multi-ring impact basins are also believed to have formed during this time period, including Crisium Basin. In the inner ring of Humboldtianum Basin is Mare Humboldtianum (Humboldtβs Sea). LOLA data reveal the relatively smooth, flat floor of the mare. The younger mare is believed to have formed during the Late Imbrian, approximately 3.8-3.6 billion years ago. Also visible in the basin are smaller craters that were partially filled in by the mare lava. Mare Humboldtianum was named after explorer Alexander von Humboldt (1769-1859) and is one of only two maria named after people, the other being Mare Smythii named after British astronomer William Henry Smyth (1788-1865. Related Links: βΊ LOLA instrument Web site Source: NASA - LRO -Multimedia Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted June 15, 2010 Author #264 Share Posted June 15, 2010 Model Helps Search for Moon Dust Fountains 06.10.10 In exploration, sometimes you find more than what you're looking for, including things that shouldnβt be there. As the Apollo 17 astronauts orbited over the night side of the moon, with the sun just beneath the horizon right before orbital "sunrise," Eugene Cernan prepared to make observations of sunlight scattered by the sun's thin outer atmosphere and interplanetary dust from comets and collisions between asteroids. The idea was to have the moon block the brilliant direct sunlight so this faint glow, called Coronal and Zodiacal Light (CZL), could be seen. They should have seen a dim "hump" of light in the middle of the horizon that gradually grew in size and intensity until it was overwhelmed by sunrise. What came next was not supposed to happen. This is a picture of coronal and zodiacal light (CZL) taken with the Clementine spacecraft, when the sun was behind the moon. The white area on the edge of the moon is the CZL, and the bright dot at the top is the planet Venus. Credit: NASA Full-resolution copy Cernan did see the CZL glow, but it had a strange companion. A slim crescent of light appeared all along the horizon, and just before sunrise, faint rays appeared, similar to the columns of light seen on Earth when sunlight pokes through a hole in a layer of clouds. On Earth, the horizon glow seen at sunrise and sunset, and the rays, are created when sunlight scatters off atmospheric moisture and dust. But the moon has almost no atmosphere -- its atmosphere is so thin, atoms and molecules there rarely collide with each other and it's technically referred to as an "exosphere". This thin atmosphere should not have produced the horizon glow seen. The sighting during Apollo 17 was not just a one-time freak event. "Similar sightings were reported on Apollo 8, 10, and 15 during planned observations of coronal and zodiacal light," says Dr. Timothy Stubbs of NASA's Goddard Space Flight Center, Greenbelt, Md., and the University of Maryland, Baltimore County. "Lunar horizon glow (LHG) was first observed between 1966 and 1968 by TV cameras aboard the Surveyor landers -- robotic precursors to the manned Apollo landings -- specifically Surveyor 5, 6 and 7, and possibly Surveyor 1," adds Stubbs. While the Apollo observations detected LHG at high altitudes β extending up to around 100 kilometers (about 62 miles) above the lunar surface, the LHG recorded by the Surveyors was much lower β within about a meter (one yard) of the surface, according to Stubbs. Deepening the mystery is that LHG was not always seen. "The astronauts on Apollo 11, 12, and 14 did not look for CZL; however, similar CZL observations were made during Apollo 16 by Ken Mattingly, but no LHG or 'streamers' were seen (to his great personal disappointment). Analyses of coronal photographs from Apollo 15 and 17 revealed an 'excess brightness' along the lunar horizon, which was interpreted as LHG produced by sunlight scattering off a high altitude 'dust atmosphere'. Similar photographs taken during Apollo 16 did not contain any excess brightness (consistent with the astronaut observations). This indicates that LHG is a variable phenomenon β sometimes you see it, sometimes you donβt," says Stubbs. This is a sketch of the lunar sunrise seen from orbit by Apollo 17 astronaut Eugene Cernan. On the right, the sketch is high- lighted to show the sources of the scattered light: red indicates Coronal and Zodiacal Glow, blue is the Lunar Horizon Glow, perhaps caused by exospheric dust, and green indicates possible "streamers" of light (crepuscular rays) formed by shadowing and scattered light. Credit: NASA Non-annotated copy While dust can produce a LHG by scattering sunlight, the presence of even an intermittent high-altitude dust atmosphere was unexpected -- the moon's exosphere is far too thin for wind to blow and suspend dust. Although the moon is constantly bombarded by meteorites (mostly microscopic) that kick up dust, "the dust concentrations inferred from LHG are much higher than expected from debris ejected by meteorite impacts alone," adds Stubbs. It has long been suggested that lunar dust gets transported electrically. For example, on the day side of the moon, solar ultraviolet radiation is strong enough to kick electrons from dust particles in the lunar soil. Removal of electrons, which have a negative electric charge, leaves the dust with a positive electric charge. Since like charges repel, the positively charged dust particles get pushed away from each other, and the only direction not blocked by more dust is up. The smaller particles likely get ejected higher because they are lighter. This might explain the different LHG observed by Surveyor and Apollo. The low-altitude glow seen by Surveyor appeared to be from larger, relatively heavy particles, while the high-altitude glow seen by Apollo astronauts was likely from the smallest particles. Small particles can get such a boost from the surface charge that they are lofted high above the surface and follow ballistic trajectories, returning to the surface under the influence of the moon's gravity. This movement of the smallest particles could make fountains of moon dust. This is a photo of low-level Lunar Horizon Glow observed by Surveyor 7; white streaks are glows observed at different times. Credit: NASA However, much remains unknown about lunar dust and the LHG. "Only a handful of LHG observations have been made, so we really know very little about it," says Stubbs. "The uncertainties associated with previous observations are largely because the instruments used were designed to measure something else." "The high altitude observations are particularly controversial. If LHG is present at high altitudes, then the suggestions are that it is produced either by sunlight scattering from dust, or by resonant scattering of sunlight from neutral sodium atoms in the exosphere. However, if sodium is producing the LHG, it should be seen up to altitudes in excess of 1,000 km (about 620 miles), but the LHG observed so far only appears to extend about 100 km (about 62 miles) above the horizon. Our predictions indicate that the LHG observations appear to be more consistent with the presence of exospheric dust." "It has been suggested that electrostatic forces play a role in the ejection of dust from the lunar surface, and its dynamics in the atmosphere, but we really donβt understand how it gets there in such high abundances. So far, LHG has only been observed near the region where day transitions to night, called the terminator, but it could well be occurring elsewhere. This begs the question: Is LHG (from atmospheric dust) a global phenomenon or is it confined to the terminator region?" "Weβre still at the stage of determining whether or not LHG is really there β this is one of the major objectives of the LADEE mission," adds Stubbs. As early as 2012, NASA could launch the Lunar Atmosphere and Dust Environment Explorer (LADEE) spacecraft that will orbit the moon and look for the LHG and exospheric dust hinted at in the Apollo observations. LADEE will look for LHG using the Ultraviolet Spectrometer (UVS) instrument, which will measure the intensity of light at different wavelengths at a point above the lunar horizon. Each potential source β sodium or dust, for example -- will produce a unique "signature" glow in ultraviolet and/or visible light. LADEE may also be able to use its star-tracker navigation cameras to observe LHG, which would provide details on the shape of the visible light scattering sources, according to Stubbs. LADEE also has a dust detector instrument to record any hits from high-altitude dust. To give the LADEE mission an idea of the best techniques and places to look for the LHG, Stubbs and his team recently created computer simulations of dust and sodium-generated glows. "The simulations show that if LHG is produced by dust, then it will be brightest in the forward scattering direction; that is, with the dust between the sun and the observer," says Dr. David Glenar of New Mexico State University. "However, for this viewing geometry, the disk of the sun needs to be blocked (e.g., by the edge of the moon), so as not to be overwhelmed by its brightness. This is why LHG has previously only been observed from the shadow of the moon close to the terminator, and this is the initial approach that is planned for LADEE/UVS." These are simulations of optical scattering sources expected to be observed above the lunar sunrise horizon (at orbital sunset), as viewed by the LADEE star tracker cameras from within the shadow of the Moon. Shown from the top are intensities due to: lunar horizon glow (LHG), coronal and zodiacal light (CZL), emissions from sodium (Na) in the lunar exosphere, and all three sources combined (LHG + CZL + Na). Under these observing conditions, LHG and CZL have comparable intensities, whereas Na emissions will be negligible. Credit: NASA Full-resolution copy "This modeling is important as it reassures us that, based on previous observations, the LADEE/UVS ought to be able to observe LHG and distinguish it from other scattering sources; i.e., it can satisfy one of its prime mission objectives. This model will be a valuable tool for analyzing and interpreting the complicated UVS scattering data in the future," said Dr. Anthony Colaprete, NASA's Ames Research Center, Moffett Field, Calif., Principal Investigator for the LADEE/UVS instrument. "Future developments of the model will include the capability to characterize the shape, size, and structure of the scattering dust grains, which will let us probe even further into the nature of the processes at work at the lunar surface," adds Dr. Denis Richard of NASA Ames and the San JosΓ© State University Research Foundation. Learning more about the strange lunar atmosphere with its potential fountains of sticky and abrasive moon dust is essential for future human exploration. "LHG could be telling us that the moonβs atmosphere is much dustier than is typically thought. It was well-reported that the Apollo astronauts found lunar dust to be a significant nuisance when exploring the moon, and itβs likely that these problems were exacerbated by electrostatic (static cling) effects. So a better understanding of the behavior of dust in the lunar environment would facilitate the development of more effective mitigation techniques," says Stubbs. "The scattering of sunlight by dust in the lunar atmosphere could mean that the moon is not as good a location for sensitive astronomical observations as has previously been assumed. This characteristic of the lunar environment needs to be well characterized before an informed judgment regarding the benefit of lunar-based telescopes can be made," adds Stubbs. The team includes researchers from NASA Goddard, NASA Ames, the University of Maryland, Baltimore County, New Mexico State University, Las Cruces, N.M., San Jose State University, San Jose, Calif., and NASA's Lunar Science Institute, which is managed by NASA Ames. Stubbs' research was published in Planetary and Space Science in April, and was funded by the NASA Lunar Reconnaissance Orbiter Participating Scientists program and the NASA Lunar Advanced Science and Exploration Research program. The LADEE mission and UVS instrument are funded by the NASA Science Mission Directorate. More about LADEE Bill Steigerwald NASA Goddard Space Flight Center Source: NASA - Missions - LADEE Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted June 15, 2010 Author #265 Share Posted June 15, 2010 Research Suggests Water Content of Moon's Interior Underestimated 06.14.10 Earthrise as seen from Apollo 8. Image Credit: NASA NASA-funded scientists estimate from recent research that the volume of water molecules locked inside minerals in the moonβs interior could exceed the amount of water in the Great Lakes here on Earth. Scientists at the Carnegie Institutionβs Geophysical Laboratory in Washington, along with other scientists across the nation, determined that the water was likely present very early in the moonβs formation history as hot magma started to cool and crystallize. This finding means water is native to the moon. βFor over 40 years we thought the moon was dry,β said Francis McCubbin of Carnegie and lead author of the report published in Monday's Online Early Edition of the Proceedings of the National Academy of Sciences. βIn our study we looked at hydroxyl, a compound with an oxygen atom bound with hydrogen, and apatite, a water-bearing mineral in the assemblage of minerals we examined in two Apollo samples and a lunar meteorite.β McCubbinβs team utilized tests which detect elements in the parts per billion range. Combining their measurements with models that characterize how the material crystallized as the moon cooled during formation, they found that the minimum water content ranged from 64 parts per billion to 5 parts per million. The result is at least two orders of magnitude greater than previous results from lunar samples that estimated water content of the moon to be less than 1 parts per billion. "In this case, when we talk about water on the moon, we mean water in the structural form hydroxyl,β said Jim Green, director of the Planetary Science Division at NASA Headquarters in Washington. βThis is a very minor component of the rocks that make up the lunar interior.β The origin of the moon is now commonly believed to be the result of a Mars-sized object that impacted the Earth 4.5 billion years ago. This impact put a large amount of material into Earthβs orbit that ultimately compacted to form the moon. The lunar magma ocean that is thought to have formed at some point during the compacting process, began to cool. During this cooling, water either escaped or was preserved as hydroxyl molecules in the crystallizing minerals. Previous studies found evidence of water both on the lunar surface and inside the moon by using respectively, remote sensing data from the Indian spacecraft Chandrayaan-1 and other lunar sample analysis. Carnegie researchers looked within crystalline rocks called KREEP (K for potassium; REE, for rare Earth elements; and P for phosphorus). These rocks are a component of some lunar impact melt and basaltic rocks. βSince water is insoluble in the main silicates that crystallized, we believed that it should have concentrated in those rocks,β said Andrew Steele of Carnegie and co-author of the report. βThatβs why we selected KREEP to analyze.β The identification of water from multiple types of lunar rocks that display a range of incompatible trace element signatures indicates that water may be at low concentrations but ubiquitous within the moon's interior, potentially as early as the time of lunar formation and magma ocean crystallization. βIt is gratifying to see this proof of the hydroxyl contents in lunar apatite,β said lunar scientist Bradley Jolliff of Washington University in St. Louis. βThe concentrations are very low and, accordingly, they have been until recently nearly impossible to detect. We can now finally begin to consider the implications - and the origin - of water in the interior of the moon.β The research was funded by the NASA Astrobiology, Mars Fundamental Research, and the Lunar Advanced Science and Exploration Research programs in NASAβs Planetary Division in Washington. Source: NASA - Moon and Mars - Features Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted June 15, 2010 Author #266 Share Posted June 15, 2010 (edited) Moon Water More Abundant than Previously Believed 14 June 2010NASA-funded scientists estimate that the volume of water molecules locked in minerals in the moon's interior could exceed the volume of water in the Great Lakes here on Earth. Scientists at the Carnegie Institution's Geophysical Laboratory, along with scientists across the nation, determined that the water was likely present very early in the moon's formation history as the hot magma started to cool and crystallize. The result means water is native to the moon; it's found in its structural form, hydroxyl, a very minor component of the rocks that make up the lunar interior.Source: NASA Channel - YouTube Edited June 15, 2010 by Waspie_Dwarf formatting. Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted June 16, 2010 Author #267 Share Posted June 16, 2010 Mare Moscoviense 06.15.10 Image credit: NASA/Goddard No larger image available Mare Moscoviense 06.15.2010 - Mare Moscoviense is one of the few large maria located on the far side of the Moon. LOLA data reveal the lowest point inside Titov crater to be about 2.7 km below the lunar datum. In contrast, the highest point on the rim of the basin rests about 3 km above lunar datum. According to the LOLA data, the total relief for the basin surrounding Mare Moscoviense is 5.7km. Although there are just as many impact basins on the lunar far side as the near, the extensive lunar volcanism seen on the near side is lacking on the far side of the Moon. Mare Moscoviense is an example of one of the few maria found on the lunar far side. Related Links: βΊ LOLA instrument Web site Source: NASA - LRO -Multimedia Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted June 18, 2010 Author #268 Share Posted June 18, 2010 The Depths of Mare Ingenii 06.17.10 Mare Ingenii may be best known for its prominent lunar swirls, which are high albedo surface features associated with magnetic anomalies. However, lunar swirls are not the only unique geologic feature found in the farside "sea of cleverness." Impact craters are visible everywhere on the moon, but pits are rare. This pit in Mare Ingenii, the "sea of cleverness," is about 130 meters (427 feet) in diameter! Image width is 550 meters (1,805 feet), illumination is from the upper right, LROC Frame: NAC M128202846LE. Credit: NASA/Goddard/Arizona State University > Larger image The high-resolution cameras aboard the Japanese SELENE/Kaguya spacecraft first discovered this irregularly-shaped hole, visible in the above image at LROC's 0.55 m/pixel resolution. The boulders and debris resting on the floor of the pit are partially illuminated (left side of the pit, above image) and probably originated at the surface, falling through the pit opening during collapse. Arrow indicates location of pit. "S" indicates one of the numerous lunar swirls located in this region. Image is a portion of LROC WAC mosaic, 200 meters per pixel resolution; image width is 160 km (100 miles). Credit: NASA/Goddard/Arizona State University > Larger image A pit in the Marius Hills region, previously discovered by the JAXA SELENE/Kaguya mission, is thought to be a skylight into a lava tube in the rille-riddled region. Similar to the Marius Hills pit, the pit in Mare Ingenii is probably the result of a partially collapsed lava tube. However, the numerous volcanic features of the Marius Hills (such as the prominent rilles and domes) are not found in Mare Ingenii. Source: NASA - LRO - News and Media Resources Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted June 20, 2010 Author #269 Share Posted June 20, 2010 (edited) Malapert 06.18.10 Located near the lunar South Pole, the Malapert region (85.99 S, 357.07 E) is an interesting site for lunar exploration. In addition to revealing the elevation of different points on the lunar surface, such as the topographically high Malapert Massif, LOLA data can also be used to classify surface roughness and to model how much sunlight different areas on the lunar surface receive for given amounts of time. With these models, scientists can find places that never receive sunlight, commonly referred to as permanently shadowed regions, as well as those that are constantly illuminated. LOLA data can also be used to determine how easily an area on the Moon could communicate with Earth by switching the βlight sourceβ in illumination models to βEarth.β Areas with high βilluminationβ in this situation have better visibility from Earth (people on Earth can see them most often), and therefore have better communication pathways between the Earth and the Moon. LOLA data have found the rim of Malapert Massif to have high illumination. Malapert Massif also has exceptional Earth visibility, and because of its excellent communication potential (and interesting science potential!), the Malapert region has been suggested as a site for future lunar exploration. Source: NASA - LRO -Multimedia Edited June 26, 2010 by Waspie_Dwarf formatting. Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted June 20, 2010 Author #270 Share Posted June 20, 2010 Orientale Basin 06.18.10 The Orientale basin is the youngest of the large lunar basins. The distinct outer ring is about 950 km from east-to-west, the full width of the LROC WAC mosaic is 1350 km. Credit: NASA/GSFC/University of Arizona The LROC team is producing preliminary large area mosaics with Wide Angle Camera (WAC) images now that enough data has been collected to derive inflight calibration coefficients and determine photometric corrections. The mosaic above is from images collected by the WAC in monochrome mode. When the sun is low on the horizon, color and reflectance variations are muted, so instead of imaging in the typical seven-color mode, image data from only one filter is read out. This gives a beautiful look at topography and morphology; later, when the sun is higher in the sky, the area is re-imaged in color, and the surface features can be correlated to their color signatures. Because the mosaic is preliminary, it still has some areas that appear black where image data was not included. The mosaic is of the multi-ring basin Orientale, the youngest of the large lunar basins. Orientale is only partially flooded by later eruptions of mare basalt, unlike basins like Imbrium, so its internal structure is still visible. This view into the interior can help us learn more about basin formation and the mechanics of how basins develop their concentric rings. Orientale is the site of two exploration regions of interest; one was the subject of a past featured image, the other is located near Kopff crater inside the basin. Kopff has unusual fractures in its floor (see NAC detailed view below), and the impact crater may have been modified by later volcanic activity, making it an exciting place to visit. A NAC view inside one of the fractures on the floor of Kopff crater, a 41 km crater within the Orientale basin and near the Orientale 2 exploration region of interest. Image M122794259RE, scene width is 670 m. Credit: NASA/GSFC/Arizona State University Arrow indicates the approximate location of the NAC detail above within Orientale basin. Credit: NASA/GSFC/Arizona State University While LROC NAC images give unprecedented detailed views of the surface, WAC mosaics provide a synoptic view of the catastrophic power of large impact events, like the one that formed the Orientale basin. Explore the full-resolution NAC image of Kopff, and the full-resolution WAC mosaic of Orientale! Source: NASA - LRO - Multimedia Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted June 24, 2010 Author #271 Share Posted June 24, 2010 Ten Cool Things Seen in the First Year of LRO 06.23.10 Having officially reached lunar orbit on June 23rd, 2009, the Lunar Reconnaissance Orbiter (LRO) has now marked one full year on its mission to scout the moon. Maps and datasets collected by LROβs state-of-the-art instruments will form the foundation for all future lunar exploration plans, as well as be critical to scientists working to better understand the moon and its environment. In only the first year of the mission, LRO has gathered more digital information than any previous planetary mission in history. To celebrate one year in orbit, here are ten cool things already observed by LRO. Note that the stories here are just a small sample of what the LRO team has released and barely touch on the major scientific accomplishments of the mission. If you like these, visit the official LRO web site at www.nasa.gov/LRO to find out even more! The Coldest Place in the Solar System One of LRO''s observations from the past year goes beyond cool to absolutely frigid. Diviner, LRO's temperature instrument, found a place in the floor of the moon's Hermite Crater that was detected to be -415 degrees Fahrenheit (-248 Celsius) making it the coldest temperature measured anywhere in the solar system. For comparison, scientists believe that Pluto's surface only gets down to about -300 degrees Fahrenheit (-184 Celsius). Extremely cold regions similar to the one in Hermite Crater were found at the bottoms of several permanently shaded craters at the lunar south pole and were measured in the depths of winter night. Image Credit: NASA/Goddard/University of California, Los Angeles βΊ Larger image βΊ Learn more about the moon's coldest places Astronauts' First Steps on the Moon On July 20, 1969, NASA added a page to the history books when Apollo 11 astronauts Neil Armstrong and Buzz Aldrin were the first humans to set foot on the moon. Though their stay was only brief, Armstrong and Aldrin had about two and a half hours to track around outside the module, taking pictures and deploying a few science experiments before returning to orbit and ultimately, the safety of Earth. Images of the Apollo 11 landing site from LRO clearly show where the descent stage (about 12 feet in diameter) was left behind as well as the astronauts' tracks and the various equipment they deployed. This LRO data has important scientific value, as it provides context for the returned Apollo samples. Beyond their use for science, the images of all six manned landing sites observed by LRO provide a reminder of NASA's proud legacy of exploration and a note of inspiration about what humans are capable of in the future. Image Credit: NASA/Goddard/Arizona State University βΊ Larger image βΊ Learn more about the Apollo 11 landing site The Apollo 14 Near Miss of Cone Crater While all of the Apollo missions are fascinating, the Apollo 14 activities provided a particularly interesting story to see in the images from LRO. The mission called for Alan Shepard and Edgar Mitchell to go to Fra Maura where they would attempt to gather samples from the rim of Cone Crater. Without having the aid of the lunar rover and having to drag a cart full of scientific equipment along with them, the trek from the descent module to Cone Crater proved to be a physically intense one. After traversing nearly a mile (1400 meters), the steep incline of the crater rim, the high heart rates of the astronauts and the tight schedule of the activity resulted in mission control ordering them to gather whatever samples they could and return to the landing module. They never reached the edge of the crater. Though geologists say it did not greatly affect the success of the scientific goal, the astronauts were personally disappointed in failing to make it to the top. Images from LRO now show precisely just how far the astronauts traveled and how close they came to reaching the crater, their tracks ending only about 100 feet (30 meters) from the rim! Image Credit: NASA/Goddard/Arizona State University βΊ Larger image βΊ Learn more about the Apollo 14 mission image A Lost Russian Rover is Found Lunokhod 1 was the name of a Russian robotic rover that landed on the moon in 1970 and navigated about 6 miles (10 km) of the lunar surface over 10 months before it lost contact in September 1971. Scientists were unsure of the rover's whereabouts, though at least one team of researchers were searching for it, hoping to bounce a laser off of its retroreflector mirrors. This past March however, the LROC team announced they had spotted it, miles from the location the laser team had been searching. Using the info provided by LRO, a laser pulse was sent to Lunokhod 1 and contact was made with the rover for the first time in nearly four decades. Not only did Lunokhod 1's retroreflector return a signal, but it returned one that was about five times better than those that have routinely been returned by Lunokhod 2's mirrors over the years. Image Credit: NASA/Goddard/Arizona State University βΊ Larger image βΊ Learn more about the discovery of Lunokhod 1 The Lunar Far Side: The Side Never Seen from Earth Tidal forces between the moon and the Earth have slowed the moon' rotation so that one side of the moon always faces toward our planet. Though sometimes improperly referred to as the "dark side of the moon," it should correctly be referred to as the "far side of the moon" since it receives just as much sunlight as the side that faces us. The dark side of the moon should refer to whatever hemisphere isn't lit at a given time. Though several spacecraft have imaged the far side of the moon since then, LRO is providing new details about the entire half of the moon that is obscured from Earth. The lunar far side is rougher and has many more craters than the near side, so quite a few of the most fascinating lunar features are located there, including one of the largest known impact craters in the solar system, the South Pole-Aitken Basin. The image highlighted here shows the moon's topography from LRO's LOLA instruments with the highest elevations up above 20,000 feet in red and the lowest areas down below -20,000 feet in blue. Image Credit: NASA/Goddard βΊ Larger image βΊ Learn more about the far side of the moon Counting Craters and Boulders The LRO Camera (LROC) has a resolution about ten times better than any previous lunar orbiter missions. That means for every pixel imaged by other spacecraft, LROC gathers 100 pixels in that same area, enough to distinguish details never before possible. One of the most striking ways this manifests itself is in the ability to make out detailed craters and individual boulders, some no larger than a few feet on the lunar surface. In order to understand the history of the lunar surface and its features and mechanisms, scientists look at the abundance, size, shape, and distribution of both craters and boulders. By comparing and analyzing these feature counts across different regions as well as other places like the Earth and Mars, we can gain a better understanding of our solar system's natural history. With the increased resolution of the LRO Camera as well as the new information gathered by LRO's other instruments, scientists can characterize the moon's surface in ways never before possible. This information will be critical for both science and future exploration plans. Not only that, but now thanks to the "Moon Zoo" (http://www.moonzoo.org) the public can get involved doing their own crater and boulder counts to aid in the research. With hundreds of gigabytes of new data returning daily, the contribution of "citizen scientists" can play a crucial part in lunar science. Image Credit: NASA/Goddard/Arizona State University βΊ Larger image βΊ Learn more about crater and boulder counting Mountains on the Moon On the Earth, we are taught that mountains form over millions of years, the result of gradual shifting and colliding plates. On the moon however, the situation is quite different. Even the largest lunar mountains were formed in minutes or less as asteroids and comets slammed into the surface at tremendous velocities, displacing and uplifting enough crust to create peaks that easily rival those found on Earth. On a few occasions in the past year, NASA has tilted the angle of LRO to do calibrations and other tests. In such cases the camera has the opportunity to gather oblique images of the lunar surface like the one featured here of Cabeus Crater providing a dramatic view of the moon's mountainous terrain. Cabeus Crater is located near the lunar south pole and contains the site of the LCROSS mission's impact. Early measurements by several instruments on LRO were used to guide the decision to send LCROSS to Cabeus. During the LCROSS impact LRO was carefully positioned to observe both the gas cloud generated in the impact, as well as the heating at the impact site. Image Credit: NASA/Goddard/Arizona State University βΊ Larger image βΊ Learn more about mountains on the moon Lunar Rilles: Mysterious Channels on the Moon Rilles are long, narrow depressions on the lunar surface that look like river channels. Some are straight, some curve, and others, like the ones highlighted here, are called "sinuous" rilles and have strong meanders that twist and turn across the moon. Rilles are especially visible in radar imagery, like that gathered by LRO's Mini-RF instrument. The formation of lunar rilles is not well understood. It is believed there may be many different formation mechanisms including ancient magma flows and the collapse of subterranean lava tubes. Imagery from LRO will help researchers to better understand these mysterious "river-like" lunar features. Image Credit: NASA/JHUAPL/LSI βΊ Larger image βΊ Learn more about lunar rilles Lunar Pits LRO has now collected the most detailed images yet of at least two lunar pits, quite literally giant holes in the moon. Scientists believe these holes are actually skylights that form when the ceiling of a subterranean lava tube collapses, possibly due to a meteorite impact punching its way through. One of these skylights, the Marius Hills pit, was observed multiple times by the Japanese SELENE/Kaguya research team. With a diameter of about 213 feet (65 meters) and an estimated depth of 260 to 290 feet (80 to 88 meters) it's a pit big enough to fit the White House completely inside. The image featured here is the Mare Ingenii pit. This hole is almost twice the size of the one in the Marius Hills and most surprisingly is found in an area with relatively few volcanic features. Image Credit: NASA/Goddard/Arizona State University βΊ Larger image βΊ Learn more about the lunar pits Areas of Near Constant Sunlight at the South Pole One of the most vital resources LRO is searching for on the moon is solar illumination. Light from the sun provides both warmth and a source of energy, two critical constraints to exploration efforts. The moon's axis is only slightly tilted so there are areas in high elevations at its poles that remain almost constantly exposed to the sun. Using LRO's precise measurements of topography scientists have been able to map illumination in detail, finding some areas with up to 96% solar visibility. Such sites would have continuous sun for approximately 243 days a year and never have a period of total darkness for more than 24 hours. Image Credit: NASA/Goddard βΊ Larger image βΊ Learn more about lunar illumination conditions βΊ View a video about these images βΊ View Geeked on Goddard Blog entry For additional image sizes and related links visit, βΊ svs.gsfc.nasa.gov/vis/a010000/a010500/a010595/ Andrew Freeberg NASA's Goddard Space Flight Center Source: NASA - LRO - News and Media Resources Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted June 24, 2010 Author #272 Share Posted June 24, 2010 NASA | Ten Cool Things Seen in the First Year of LRO 23 June 2010To celebrate one year in orbit, here are ten cool things already observed by NASA's Lunar Reconnaissance Orbiter. Note that the stories here are just a small sample of what the LRO team has released and barely touch on the major scientific accomplishments of the mission.Source: NASAexplorer Channel - YouTube Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted June 25, 2010 Author #273 Share Posted June 25, 2010 Lunar Orbiter Marks First Year at Moon 24 June 2010The Lunar Reconnaissance Orbiter, LRO, has completed one full year of scouting the moon. Since officially reaching lunar orbit on June 23nd, 2009, LRO's observations have led to a number of major scientific accomplishments. Shown here are ten of the many 'cool' things LRO has seen over the last twelve months.Source: NASA Channel - YouTube Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted June 26, 2010 Author #274 Share Posted June 26, 2010 The Earth From The Moon 06.24.10 > View larger image The Earth as seen from the Moon! LROC NAC mosaic of images snapped on 12 June 2010 during a calibration sequence (Images E130954785L and E130954785R). Credit: NASA/Goddard/Arizona State University All cameras are susceptible to scattered light. You may have seen scattered light in pictures you have taken looking towards the Sun. Sunlight reflects off the optics and sometimes off the structure of the lens, and often appears as a gradient of brightness across the image. Attaching a baffle to your camera, like we did with the LROC Wide and Narrow Angle Cameras, can minimize this effect. More subtle effects are often present but usually you simply just don't notice artifacts because of strong color contrasts in the scene. Since the Moon has only very small color contrasts, the LROC team must characterize even subtle scattered light effects within the 7-color Wide Angle Camera (WAC) images. Changes in composition (rock types) result in subtle differences of color, typically about 10% or less. For scientists to make accurate interpretations of WAC color maps, the amount of scattered light must be quantified (and preferably corrected). One way of measuring scattered light is imaging a bright object against a dark background. From the Moon, the Earth serves that function well. While a series of WAC calibration images of the Earth were being acquired, the Narrow Angle Camera (NAC) was shuttered to capture this spectacular Earth view. The bottom of the Earth was clipped because the prediction of the exact time when the cameras' fields of view would cross the Earth was off by a few seconds. Since the NAC acquires only one line of a picture at a time, the spacecraft had to be nodded across the Earth to build up the scene. The NAC Earth view is actually a mosaic of NAC-Left and NAC-Right images put together after calibration. The distance between the Moon and the Earth was 372,335 km when the picture was taken, with a pixel scale of about 3.7 km, and the center of this view of Earth is 25Β°N latitude, 114Β°E longitude (a few hundred kilometers north of Hong Kong). > View larger image AP: Arabian Peninsula; CS: Caspian Sea; H: Himalayan Mountains; L: Lena River; I: Indian Ocean; A: Australia; J: Japan; P: Pacific Ocean; large yellow arrow indicates approximate position of the North Pole. Credit: NASA/Goddard/Arizona State University It was a beautiful clear summer day over the North Pole. You can see ice covering most of the Arctic Ocean with a few leads of open water (dark) starting to open up. If you look very close you can follow the Lena River upstream from the Arctic Ocean all the way to Lake Baikal. Much of the Middle East was clear and you can trace spectacular swirl patterns of folded rock layers through Iran, Afghanistan, and Pakistan. These mountains formed as the Eurasian and Arabian tectonic plates collided. Browse the full-sized image at the LRO Camera website maintained by Arizona State University. Source: NASA - LRO - Multimedia Link to comment Share on other sites More sharing options...
Waspie_Dwarf Posted June 26, 2010 Author #275 Share Posted June 26, 2010 Goddard Crater 06.25.10 > View larger image Goddard Crater is located along the Moonβs eastern limb (14.8 N, 89.0 E). LOLA data show the floor of the 90 km diameter crater to be relatively flat and smooth. The crater is named after pioneering rocket scientist Robert H. Goddard (1882-1945). Considered to be to be the father of modern rocketry, Goddard built the worldβs first liquid-fueled rocket. Incidentally, the LOLA instrument was built at the one NASA Center named for Robert H. Goddard, Goddard Space Flight Center in Greenbelt, MD. The Lunar Reconnaissance Orbiter on which LOLA flies was also built at Goddard Space Flight Center. To learn more about Robert H. Goddard, visit Dr. Robert H. Goddard, American Rocketry Pioneer βIt is difficult to say what is impossible, for the dream of yesterday is the hope of today and the reality of tomorrow.β -- Dr. Robert Hutchings Goddard Source: NASA - LRO -Multimedia Link to comment Share on other sites More sharing options...
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