Posted on by Nancy Atkinson

One Year of the Lunar Reconnaissance Orbiter: Top Ten Finds

Orbiter
Lunar Reconnaissance Orbiter. Credit: NASA

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One year ago today, the Lunar Reconnaissance Orbiter (LRO) officially reached orbit about the Moon, and in the past 12 months has gathered more digital information than any previous planetary mission in history. NASA says that maps and datasets collected by LRO’s 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. To celebrate one year in orbit, here are ten great observations made by LRO.

LRO's Diviner instrument found the coldest place in the solar system. Credit: NASA/Goddard/University of California, Los Angeles

1. Coldest Place in the Solar System.

If you think Pluto, a KBO, or the farthest reaches of our solar system are cold, a location closer to Earth is actually colder. 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.

Enlargement of area surrounding Apollo 11 landing site. Credit: NASA/GSFC/Arizona State University

2. Where Humans Have Walked on the Moon

LRO’s views of the Apollo landing sites are nothing short of stunning, not to mention exciting. Above is LRO’s latest looks at the Apollo 11 landing site, which clearly shows 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.

A pit on the Moon. Credit: NASA/Goddard/Arizona State University

3. Caves on the Moon

What could be more exciting than finding a cave on the Moon, a potential future lunar habitat for human explorers? 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.

The Russian Lunokhod rover was imaged by LRO. Credit: NASA/Goddard/Arizona State University

4. Finding Missing Spacecraft

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.

The Apollo 14 crew came close to seeing the rim of Cone Crater, but not quite. Credit: NASA/Goddard/Arizona State University

5. Apollo 14’s Near Miss of Seeing Cone Crater.

When the Apollo 14 crew of Alan Shepard and Edgar Mitchell walked across their landing site at Fra Maura, they hoped to be able to gather samples from the rim of Cone Crater. But they didn’t ever find the rim, and without a roadmap or guideposts along the way to help them find it, (and also they didn’t have the benefit of riding on the lunar rover so had to walk the entire time). They walked nearly a mile (1400 meters) and the steep incline of the crater rim made the climb difficult, raising the astronaut’s heart rates. Plus 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!

The rim of Cabeus Crater. Credit: NASA/Goddard/Arizona State University

6. 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.

Lunar rilles. Image Credit: NASA/JHUAPL/LSI

7. 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.

Areas of constant sunlight on the Moon's south pole. Image Credit: NASA/Goddard

8. 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.

With Moon Zoo, you can count craters and boulders on the Moon to help lunar scientists. Credit: NASA/Goddard/Arizona State University

9. Moon Zoo lets you Help Lunar Scientists.

The latest Citizen Science project from the Zooniverse, Moon Zoo uses about 70,000 high resolution images gathered by LRO, and in these images are details as small as 50 centimeters (20 inches) across. ‘Zooites’ are asked to categorize craters, boulders and more, including lava channels and later, comparing recent LRO images to ones taken years ago by other orbiting spacecraft.

The first tasks are counting craters and boulders. By comparing and analyzing these feature counts across different regions as well as other places like the Earth and Mars, Zooites can help scientists gain a better understanding of our solar system’s natural history.

The Moon's far side -- the part we never see from Earth. Credit: NASA/Goddard

10. Getting a Good Look at the Far Side.

Tidal forces between the moon and the Earth have slowed the Moon’s 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.

See the LRO website for more info.

Source: NASA

Posted on by Nancy Atkinson

Very Clever! LRO Views Huge Lava Tube Skylight in Mare Ingenii

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

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Is this a window into the interior of the Moon, and an entrance to a potential future lunar habitat? The Lunar Reconnaissance Orbiter Camera has taken a closer look at what is thought to be a skylight into a lava tube in the Mare Ingenii (The Sea of Cleverness) region, one of the few lunar mare features on the far side of the Moon. This skylight is huge — about 130 meters (427 feet) in diameter — and is probably the result of a partially collapsed lava tube. But lunar geologists really weren’t expecting to see this kind unusual feature in this region. Previously, a skylight, or open pit was found in the Marius Hills region in the Ocean of Storms on the near side which is filled with volcanic domes and rilles where a lava tube might form. However, those kinds of volcanic features are not found in Mare Ingenii. LRO will definitely be taking additional looks at this pit.

The Japanese SELENE/Kaguya spacecraft first discovered this irregularly-shaped hole, visible in the top 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) 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

This could be an important find for several reasons. Lava tubes are important in understanding how lava was transported on the early moon, but they could also provide a home to future human explorers. This one on the far side would be a great place to set up a base for future telescopes proposed for observations out into the Universe from the Moon’s far side. The Moon’s surface is a harsh place, the human body doesn’t do well when exposed to the constant radiation present on the Moon’s atmosphere-less environment. Long term human presence would work if astronauts could spend most of their time shielded underground. While excavating a hole large enough to fit an entire moon colony in it would be a huge engineering challenge, these lava tubes could provide ready-made locations for a well-shielded base.

Read our previous article about the pit in the Marius Hills.

Here’s a look at a huge lava tube in Hawaii. It looks almost man-made, but is a natural feature created by volcanism:

Thurston lava tube is located on Kilauea in Hawaii. Credit: P. Mouginis-Mark, LPI

How lava tubes form: when lava flows out onto the surface, it cools on top and may form a solid roof. The roof insulates the still-liquid lava below it, allowing it to continue to flow, sometimes for several kilometers. At the end of the eruption, the lava can drain completely out of the tube, leaving a hollow remnant of the flow that forms an underground cavern. This tube, called Thurston Tube, is about 3 meters in height.

Sources: LROC website, Planetary Blog

Posted on by Nancy Atkinson

Water Could Be Widespread in Moon’s Interior

Moon rocks from the Apollo 11 mission. Credit: NASA

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A new look at Moon rocks from the Apollo missions, along with a lunar meteorite show a much higher water content in the Moon’s interior than previously thought. Using secondary ion mass spectrometry (SIMS) which can detect elements in the parts per million range, scientists at the Carnegie Institution’s Geophysical Laboratory found the minimum water content ranged from 64 parts per billion to 5 parts per million—at least two orders of magnitude greater than previous results. The science team says their research suggests that the water was preserved from the hot magma that was present when the Moon began to form some 4.5 billion years ago. “The concentrations are very low and, accordingly, they have been until recently nearly impossible to detect,” said team member Bradley Jolliff of Washington University in St. Louis. “We can now finally begin to consider the implications—and the origin—of water in the interior of the Moon.”

The prevailing belief is that the Moon came from a giant-impact event, when a Mars-sized object hit the Earth and the ejected material coalesced into the Moon. In this new study of lunar samples, scientists determined that water was likely present very early in the formation history as the hot magma started to cool and crystallize. This result means that water is native to the Moon.

The SIMS technique measures hydroxyl by bombarding the grains of a type of phosphorous, water-bearing mineral called apatite with high-energy particles and counting the ions that are ejected. Based on the SIMS measurements, the scientists authors place the lower limit for the total lunar water at 100 times greater than previous estimates, and speculate that water may be “ubiquitous” in the moon’s interior.

The study could alter current theories about lunar magmatism (how igneous rock formed from magma), and how the moon formed and evolved.

Water is showing up in all sorts of unexpected places on the Moon. In September of 2009, a trio of spacecraft detected a ubiquitous layer of a combination of water (H2O) and hydroxyl (OH) that resides in upper millimeter of the lunar surface. It doesn’t actually amount to much; only about two tablespoons of water is believed to be present in every 1,000 pounds (450 kg). Then in October of 2009, the LCROSS impactor and spacecraft detected “buckets” of water in the permanently shadowed region of Cabeus crater near the moon’s south pole.

In 2008 water was found inside volcanic glass beads in Apollo Moon rocks, which represent solidified magma from the early moon’s interior. That finding led to this new study, using the SIMS. The scientists combined the measurements taken with the spectrometer with models that characterize how the lunar magma crystallized as the Moon cooled. They then inferred the amount of water in the apatite’s source magma, which allowed them to extrapolate the result to estimate the total amount of water that is present on the moon.

“For over 40 years we thought the Moon was dry,” said lead author of the new study, Francis McCubbin.

The research is published in the on-line early edition of the Proceedings of the National Academy of Sciences the week of June 14.

Posted on by Nancy Atkinson

The Earth and Moon May Have Formed Later Than Previously Thought

The collision between "Proto-Earth" and Theia, from which the Earth and Moon were created 4,500-4,400 million years ago. Both planets had a massive iron core when they collided and created the Moon and Earth.

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The Earth and Moon were created as the result of a giant collision between two planets the size of Mars and Venus. Until now it was thought to have happened when the solar system was 30 million years old or approximately 4.5 billion years ago. But new research shows that the Earth and Moon may have formed much later – perhaps up to 150 million years after the formation of the solar system.

“We have determined the ages of the Earth and the Moon using tungsten isotopes, which can reveal whether the iron cores and their stone surfaces have been mixed together during the collision,” said Tais W. Dahl, from the Niels Bohr Institute at the University of Copenhagen in collaboration with professor David J. Stevenson from the California Institute of Technology (Caltech).

The planets in the solar system were created by collisions between planetary embryos orbiting the newborn sun. In the collisions the small planets congealed together and formed larger and larger planets. When the gigantic collision occurred that ultimately formed the Earth and Moon, it happened at a time when both planetary bodies had a core of metal (iron) and a surrounding mantle of silicates (rock). But when did it happen and how did it happen? The collision took place in less than 24 hours and the temperature of the Earth was so high (7000º C), that both rock and metal must have melted in the turbulent collision. But were the stone mass and iron mass also mixed together?

The age of the Earth and Moon can be dated by examining the presence of certain elements in the Earth’s mantle. Hafnium-182 is a radioactive substance, which decays and is converted into the isotope tungsten-182. The two elements have markedly different chemical properties and while the tungsten isotopes prefer to bond with metal, hafnium prefers to bond to silicates, i.e. rock.

It takes 50-60 million years for all hafnium to decay and be converted into tungsten, and during the Moon forming collision nearly all the metal sank into the Earth’s core. But did all the tungsten go into the core?

“We have studied to what degree metal and rock mix together during the planet forming collisions. Using dynamic model calculations of the turbulent mixing of the liquid rock and iron masses we have found that tungsten isotopes from the Earth’s early formation remain in the rocky mantle,” said Tahl.

The new studies imply that the moon forming collision occurred after all of the hafnium had decayed completely into tungsten.

“Our results show that metal core and rock are unable to emulsify in these collisions between planets that are greater than 10 kilometers in diameter and therefore that most of the Earth’s iron core (80-99 %) did not remove tungsten from the rocky material in the mantle during formation” said Dahl.

The result of the research means that collision that created the Earth and the Moon may have occurred as much as 150 million years after the formation of the solar system, much later than the 30 million years that was previously thought.

The research results have been published in the scientific journal, Earth and Planetary Science Letters.

From a University of Copenhagen press release.

Posted on by Nancy Atkinson

Japan Shoots for Robotic Moon Base by 2020

Concept drawing of a robotic lunar base. Credit: JAXA

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These ARE the droids we’ve been looking for. The Japanese space agency, JAXA, has plans to build a base on the Moon by 2020. Not for humans, but for robots, and built by robots, too. A panel authorized by Japan’s prime minister has drawn up preliminary plans of how humanoid and rover robots will begin surveying the moon by 2015, and then begin construction of a base near the south pole of the moon. The robots and the base will run on solar power, with total costs about $2.2 billion USD, according to the panel chaired by Waseda University President Katsuhiko Shirai.

Moon base robot. Credit: JAXA

Some of the planned droids weigh about 300 kg (660 pounds) and move on tank-like treads. Reportedly, they will be able to operate within a 100 km (60 mile) radius of the base. They’ll be equipped with solar panels, seismographs to investigate the moon’s inner structure, high-def cameras, and arms to gather rock samples, which will be returned to Earth via a sample return rocket.

The exact location for the base will be chosen from high-resolution images returned by Japan’s Kaguya orbiter, which has provided stunning images of the Moon’s surface.

Previously, JAXA had set a goal of constructing a manned lunar base starting in about 2030, and apparently, the robotic base would be a precursor. That plan calls for astronauts to visit the Moon by around 2020 which is about the same timetable as the Indian Space Research Organization (ISRO) is hoping to have a manned mission to the Moon. The China National Space Administration (CNSA) has said they would like to have a manned lunar mission in 2030. NASA? Not sure yet. The Constellation program to return to the Moon has seemingly been axed, but it’s not going down without a fight from members of Congress and others. But surely, even if NASA decides an asteroid or Mars is their destination of choice, they would have to start by practicing on the Moon.

Let’s all work together on this and perhaps returning to the Moon will actually happen.

Source: NODE via PopSci

Posted on by Nancy Atkinson

Citizen Science Goes to the Moon

Screen shot from Moon Zoo.

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Have you ever wanted to explore the Moon? Well, now you can as a virtual astronaut, and you can help lunar scientists answer important questions, as well. New from the Zooniverse — from the same folks that brought you Galaxy Zoo — is Moon Zoo. “We’re asking citizen scientists to help answer different aspects of lunar science and outstanding questions that we still have,” said Dr. Katherine Joy from the Lunar and Planetary Institute and a Moon Zoo science team member.

Moon Zoo uses about 70,000 high resolution images gathered by the NASA’s newest lunar spacecraft. the Lunar Reconnaissance Orbiter. In these images are details as small as 50 centimeters (20 inches) across, and ‘Zooites’ are will be asked to catergorize craters, boulders and more, including lava channels and even all sorts of different spacecraft sitting on the Moon’s surface.

How fun is this latest Zoo project?

“Actually, I have to say after a few days of playing with it I find it much more addictive than the others,” said Chris Lintott, head “zookeeper” of the Zooniverse and chair of the Citizen Science Alliance. “Galaxy Zoo was bad enough but I’m obsessed with the Moon now. I can’t quite believe the variety of the places we’re seeing. People think the Moon is this boring place – they say, ‘we know what it looks like, it’s just grey and flat, right?’ But actually it has its own landscape that is really quite dramatic, especially when the sun is low, so it’s a world well worth exploring.”

Want to join in? Go to the Moon Zoo website, and if you’ve participated any of the previous Galaxy Zoo or Solar Storm Watch projects, you can use the same username and password. If not, it’s easy to sign up.

Under the “How to Take Part” tab you’ll find a tutorial that will teach you how to participate in Moon Zoo.

The two main biggest tasks right now are the Crater Survey, where you can mark all the craters (down to a certain size), and Boulder Wars, where you are shown two images and you determine which has the most boulders.

But Dr. Joy said there will soon be some additional tasks, created from a wish list from lunar scientists. “One of the main tasks we really want to do is to compare these new LRO images to older Apollo panoramic camera images that were taken 40 years ago,” she said. “And what we can do is match these older images against the new images with similar lighting conditions and similar angles at which the camera was pointed at the surface and what we might be able to do is to spot differences that have occurred between 40 years ago and now, which could be in the form of say, new impact craters that have formed from incoming bolides. We might be able to spot new debris flows and landslides that have happened in the past 40 years. This can provide us information about the really recent history of the Moon.”

Questions? There’s a FAQ section and a discussion forum where you can pose queries or discuss any issues or interesting finds with other Zooites.

“We’re hoping to reach out to people that have never really looked at the Moon before in any kind of detail and get them excited about all the secrets the Moon still has,” said Dr. Joy “because there are plenty of new things that people have never looked at before.”

Listen to the May 19, 2010 edition of the 365 Days of Astronomy podcast for an interview with Katie Joy and Chris Lintott.

Posted on by Nancy Atkinson

Shocking! Lunar Craters May Be Electrified

Graphic of how the solar wind flows over the Moon. Credit: NLSI

The Moon keeps getting more interesting all the time! But now comes “shocking” news that exploring polar craters could be much harder and more dangerous than originally thought. New research shows that as the solar wind flows over natural obstructions on the moon, such as the rims of craters at the poles, the craters could be charged to hundreds of volts. “In a nutshell, what we’re finding is that the polar craters are very unusual electrical environments, and in particular there can be large surface charging at the bottom of these craters,” said William Farrell from Goddard Space Flight Center, lead author of a new research on the Moon’s environment.

The moon’s orientation to the sun keeps the bottoms of polar craters in permanent shadow, allowing temperatures there to plunge below minus 400 degrees Fahrenheit, cold enough to store volatile material like water for billions of years. And of course, any resources that may lie in those craters are of interest for any future explorers, should astronauts ever return to the Moon.
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“However, our research suggests that, in addition to the wicked cold, explorers and robots at the bottoms of polar lunar craters may have to contend with a complex electrical environment as well, which can affect surface chemistry, static discharge, and dust cling,” said Farrell, who is part of a lunar Dream Team — the Lunar Science Institute’s Dynamic Response of the Environment at the moon (DREAM) project, which is also part of NASA’s Lunar Science Institute.

Solar wind inflow into craters can erode the surface, which affects recently discovered water molecules. Static discharge could short out sensitive equipment, while the sticky and extremely abrasive lunar dust could wear out spacesuits and may be hazardous if tracked inside spacecraft and inhaled over long periods.

The solar wind is a thin gas of electrically charged components of atoms – negatively charged electrons and positively charged ions — that is constantly blowing from the surface of the sun into space. Since the moon is only slightly tilted compared to the sun, the solar wind flows almost horizontally over the lunar surface at the poles and along the region where day transitions to night, called the terminator.

The researchers created computer simulations to discover what happens when the solar wind flows over the rims of polar craters. They discovered that in some ways, the solar wind behaves like wind on Earth — flowing into deep polar valleys and crater floors. Unlike wind on Earth, the dual electron-ion composition of the solar wind may create an unusual electric charge on the side of the mountain or crater wall; that is, on the inside of the rim directly below the solar wind flow.

Since electrons are over 1,000 times lighter than ions, the lighter electrons in the solar wind rush into a lunar crater or valley ahead of the heavy ions, creating a negatively charged region inside the crater. The ions eventually catch up, but rain into the crater at consistently lower concentrations than that of the electrons. This imbalance in the crater makes the inside walls and floor acquire a negative electric charge. The calculations reveal that the electron/ion separation effect is most extreme on a crater’s leeward edge – along the inside crater wall and at the crater floor nearest the solar wind flow. Along this inner edge, the heavy ions have the greatest difficulty getting to the surface. Compared to the electrons, they act like a tractor-trailer struggling to follow a motorcycle; they just can’t make as sharp a turn over the mountain top as the electrons.

“The electrons build up an electron cloud on this leeward edge of the crater wall and floor, which can create an unusually large negative charge of a few hundred Volts relative to the dense solar wind flowing over the top,” said Farrell.

The negative charge along this leeward edge won’t build up indefinitely. Eventually, the attraction between the negatively charged region and positive ions in the solar wind will cause some other unusual electric current to flow. The team believes one possible source for this current could be negatively charged dust that is repelled by the negatively charged surface, gets levitated and flows away from this highly charged region. “The Apollo astronauts in the orbiting Command Module saw faint rays on the lunar horizon during sunrise that might have been scattered light from electrically lofted dust,” said Farrell. “Additionally, the Apollo 17 mission landed at a site similar to a crater environment – the Taurus-Littrow valley. The Lunar Ejecta and Meteorite Experiment left by the Apollo 17 astronauts detected impacts from dust at terminator crossings where the solar wind is nearly-horizontal flowing, similar to the situation over polar craters.”

“This important work by Dr. Farrell and his team is further evidence that our view on the moon has changed dramatically in recent years,” said Gregory Schmidt, deputy director of the NASA Lunar Science Institute at NASA’s Ames Research Center, Moffett Field, Calif. “It has a dynamic and fascinating environment that we are only beginning to understand.”

Next steps for the team include more complex computer models. “We want to develop a fully three-dimensional model to examine the effects of solar wind expansion around the edges of a mountain. We now examine the vertical expansion, but we want to also know what happens horizontally,” said Farrell. As early as 2012, NASA will launch the Lunar Atmosphere and Dust Environment Explorer (LADEE) mission that will orbit the moon and could look for the dust flows predicted by the team’s research.

The research was published March 24 in the Journal of Geophysical Research.

Source: NLSI

Posted on by Nancy Atkinson

Apollo Landing Sites, Now in 3-D!

Apollo 14 landing site in 3-D. Image: LRO, Anaglyph by Nathanial Burton-Bradford. Click for larger version.

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Time to grab your 3-D glasses! Just got a note from Nathanial Burton-Bradford, one of the image editing wizards we have featured here at Universe Today. His latest handiwork is creating some 3-D analglyphs of images from the Lunar Reconnaissance Orbiter, and particularly of the Apollo landing sites. As Nathanial wrote me, “In a word, WOW!” Nathanial’s images make the lunar landers really stand out and stand *up* in the images, and other features such as tracks and experiments left by the Apollo astronauts become more visible as well. See more images below, and click on the images for larger versions, or see Nathanial’s flickr page for lots more!

Apollo 15 landing site in 3-D. Image by LRO, Analglyph by Nathanial Burton Bradford. Click for larger version.

Apollo 11 landing site in 3-D. Image: LRO, Anaglyph by Nathanial Burton-Bradford. Click for larger version.
Posted on by John Carl Villanueva

Surface of the Moon

Earth's Moon
Earth's Moon

[/caption]Despite the close proximity between the Earth and the Moon, there’s a big difference between the surface of the Moon and of Earth’s. Much of the difference between the two celestial bodies is caused by the absence of the following attributes on the Moon: an atmosphere, bodies of water, and plate tectonics.

Since the Earth’s Moon doesn’t have a significant atmosphere, nothing can stop even the smallest meteoroids from striking its surface. As a result, the lunar surface is heavily cratered. As a matter of fact, tiny craters are quite common even on lunar rocks. This was observed on the Moon rocks brought home by the Apollo missions.

By contrast, small meteoroids that pass through the Earth’s atmosphere are easily vaporized and hence are not able to form craters on the land below.

The absence of liquid water on its surface has allowed the Moon to preserve much of its ancient geological features. Here on Earth, erosion can alter and cover formations over time. Plate tectonics, which is also absent on the Moon, is another big factor that makes the terrain of the two celestial bodies different.

Here on Earth, plate tectonics cause volcanic activities, earthquakes, and sea floor spreading.

Due to the lack of water and atmosphere, the lunar regolith (also called “lunar soil”) is noticeably dry and devoid of air. It also does not contain anything organic. The regolith comes from meteor impacts that has plagued the Moon since its inception.

Impact crater sizes on the lunar surface range from the tiny holes that mark lunar rocks to the really big ones like the South Pole Aitken Basin that has a diameter of approximately 2,500 km. Younger craters are superimposed over older ones. This characteristic is used by scientists to determine the relative ages of impact craters.

Basically, it has been observed that the size of impact craters on the surface of the Moon have decreased over time.

Other prominent geological features found on the surface of the Moon include maria, rilles, domes, wrinkle ridges, and grabens.

The maria, which comprise about one-third of the Moon’s near side, are made up of flows of basaltic lava formed from volcanic activities that occurred in the younger years of the Moon. They were once mistaken for seas on the surface of the Moon, hence the name. Maria is the Latin word for seas. The near side refers to the side of the Moon that is constantly facing Earth.

Here’s a list of popular craters on Earth from Universe Today.

Come October 9, 2009, LCROSS will perform a lunar impact. Find out which crater NASA has chosen for the impact. If you want to know more about the largest crater on the Moon, NASA’s got the right stuff.
There are some interesting episodes from Astronomy Cast that we’d like to recommend:
The Source of Atmospheres, the Vanishing Moon, and a Glow After Sunset
The Moon, Part 1

References:
http://www.nasa.gov/mission_pages/LRO/multimedia/lro-20100709-basin.html
http://curator.jsc.nasa.gov/lunar/letss/Regolith.pdf

Posted on by Nancy Atkinson

Awesome Image of ISS Transiting Moon

ISS transit of the Moon. Image Credit: Photo courtesy of Fernando Echeverria

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The NASA Image of the Day is a webpage that everyone should visit everyday, as there are always great images of our explorations of space and Earth. But this one has a wow factor that is off the charts. It was taken just minutes before space shuttle Discovery launched this past Monday on April 5, 2010, as the International Space Station flew across the face of the moon over Kennedy Space Center in Florida. I know people who were there who thought it was an poignant event, but here photographer Fernando Echeverria captures the event at just the right milimoment as the ISS reached the dark area on the Moon. Amazing, and such incredible detail, too! Click the image or this link to go to the NASA Image of the Day site where you can find larger versions — suitable for framing or desktops!