Apollo 15 astronauts David Scott and James Irwin practice LRV operations in Arizona, Nov. 2 1970 (Credit: NASA. Research by J.L. Pickering)
Between the years of 1969 and 1972 the astronauts of the Apollo missions personally explored the alien landscape of the lunar surface, shuffling, bounding, digging, and roving across six sites on the Moon. In order to prepare for their off-world adventures though, they needed to practice extensively here on Earth so they would be ready to execute the long laundry lists of activities they were required to accomplish during their lunar EVAs. But where on Earth could they find the type of landscape that resembles the Moon’s rugged, dusty, and — most importantly — cratered terrain?
Enter the Cinder Lakes Crater Fields of Flagstaff, Arizona.
The Cinder Lakes Crater Fields northeast of Flagstaff, near the famous San Francisco peaks and just south of the Sunset Crater volcano, were used for Apollo-era training because of the inherently lunar-like volcanic landscape. LRV practice as well as hand tool geology and lunar morphology training were performed there, as well as ALSEP – Apollo Lunar Surface Experiment Package – placement and setup practice.
The photo above shows Apollo 15 astronauts Dave Scott and Jim Irwin driving a test LRV nicknamed Grover along the rim of a small “lunar crater.” (This particular exercise was performed on Nov. 2, 1970… 44 years ago today!)
Detonation of a “lunar crater” in 1967 (USGS)
Although the craters might look similar to the ones found on the Moon, they were actually created by the USGS in 1967 by digging holes and filling them with various amounts of explosives, which were detonated to simulate different-sized lunar impact craters. The human-made craters ranged in size from 5-40 feet (1.5-12 meters) in diameter.
The two crater field sites at Cinder Lakes were chosen because of the specific surface geology: a layer of basaltic cinders covering clay beds, left over from an eruption of the Sunset Crater volcano 950 years ago. After the explosions the excavated lighter clay material spread out from the blast craters and across the fields, like ejecta from actual meteorite impacts. A total of 497 craters were made within two sites comprising 2,000 square feet.
Detonations were done in series to simulate ejected debris from cratering events of different ages. And one of the areas of Cinder Lakes was designed to specifically replicate craters found within a particular region of the Apollo 11 Mare Tranquillitatis landing site.
The completed Cinder Lakes Crater Field #1 in October 1967 (USGS)
Today only the largest craters can be distinguished at all in the publicly-accessible Cinder Lakes field, which has become popular with ATV enthusiasts. But a smaller field, fenced off to vehicles, still contains many of the original craters used by Apollo astronauts, softened by time and weather but still visible.
A couple of other areas were used as lunar analogue training fields as well, such as the nearby Merriam Crater and Black Canyon fields — the latter of which is now covered by a housing development. Geology field training exercises by Apollo astronauts were also performed at locations in Texas, New Mexico, Nevada, Oregon, Alaska, Idaho, Iceland, Mexico, the Grand Canyon, and the lava fields of Hawaii. But only in Arizona were actual craters made to specifically simulate the Moon!
Read more about the Cinder Lakes Crater Field in a presentation document (my main article source) by LPI’s Dr. David Kring, and you can find more recent photos of the Crater Lakes sites on this page by LPI’s Jim Scotti.
The impact site of the LADEE spacecraft is clear to see. Actually not really. One must compare to LROC images of the same site photographed before and after the impact to locate it. Click on the image to view the animated gif holding the pair of images. (Photo Credits: NASA/GSFC/LROC)
Ever wonder what your refrigerator’s impacting at the speed of a tank artillery shell would do to the Moon? The Lunar Reconnaissance Orbiter’s (LRO) primary camera has provided an image of just such an event when it located the impact site of another NASA spacecraft, the Lunar Atmosphere and Dust Environment Explorer (LADEE). The fridge-sized LADEE spacecraft completed its final Lunar orbit on April 18, 2014, and then crashed into the far side of the Moon. LADEE ground controllers were pretty certain where it crashed but no orbiter had found it until now. With billions of craters across the lunar surface, finding a fresh crater is a daunting task, but a new method of searching for fresh craters is what found LADEE.
The primary purpose of the LADEE mission was to search for lunar dust in the exceedingly thin atmosphere of the Moon. NASA Apollo astronauts had taken notes and drawings of incredible spires and rays of apparent dust above the horizon of the Moon as they were in orbit. To this day it remains a mystery although LADEE researchers are still working their data to find out more.
The LRO spacecraft has been in lunar orbit since 2007. With the LROC Narrow Angle Camera, LRO has the ability to resolve objects less than 2 feet across, and it was likely just a matter of finding time to snap and to search photos for a tiny impact crater.
However, the LROC team recently developed a new algorithm in software to search for fresh craters. Having a good idea where to begin the search, they decided to search for LADEE and quickly found it. The LROC team said the impact site is “about half a mile (780 meters) from the Sundman V crater rim with an altitude of about 8,497 feet (2,590 meters) and was only about two tenths of a mile (300 meters) north of the location mission controllers predicted based on tracking data.” Sundman Crater is about 200 km (125 miles) from a larger crater named Einstein.
A Google Earth map display of the Moon shows the area of the western limb and the offset of the LADEE impact site relative to the crater Einstein. The Moon’s limbs are zones rather than a distinct line because of its libration. (Photo Credit: Google, Illus. T. Reyes)
The LADEE impact site is within 300 meters of the location estimated by the LADEE team. The ground control team at Ames Research Center knew the location very well within just hours after the time of the planned impact. They had to know LADEE’s location in orbit with split-second accuracy and also know very accurately the altitude of the terrain LADEE was skimming over. LADEE was traveling at 1699 meters per second (3,800 mph, 5,574 feet/sec) upon impact.
But still, finding something as small as this crater can be difficult.
Looking at these images, the scale of lunar morphology is very deceiving. Craters that are 10 meters in diameter can be mistaken for 100 meter or even 1000 meters. The first image and third images (below) in this article are showing only a small portion of the external slope of the eastern rim of Sundman V, the satellite crater to the southeast of crater Sundman. Sundman V is 19,000 meters in diameter (19 km, 11.8 miles) whereas the first image is only 223 meters across.
The following image, which is the ratioing of “before” and “after” impact images by LROC, clearly reveals the impact scar from LADEE. LADEE’s crater is only approximately 10 feet in diameter (3 m) with the ejecta fanning out 200 meters to the west by northwest. LADEE was traveling westward across the face of the Moon that we see from Earth, reached the western limb and finally encountered Sundman.
A high resolution LROC image of the LADEE impact site on the eastern rim of Sundman V crater. The image was created by ratioing two images, one taken before the impact and another afterwards. The bright area highlights what has changed between the time of the two images, specifically the impact point and the ejecta. Full resolution of the image (click) is 1 pixel per meter [1000 m on a side]. (Credit: NASA/Goddard/Arizona State University)In the third image of this article (above), only a 1000 meter square view of the outer slope of Sundman V’s eastern rim is seen. Rather than take the difference between the two images, which is essentially what your eye-brain does with an image pair, LROC engineers take the ratio which effectively raises the contrast dramatically. Sundman V crater is on the far side of the Moon but very near the limb. At times, due to lunar libration, this site can be seen from the Earth. In the Lunar Orbiter image, below, Sundman and satellites J & V are marked. The red circle in the image below is the area in which LROC’s high resolution images reside. Furthermore, the famous Arizona meteor crater east of Flagstaff would also easily fit inside the circle.
This Lunar Orbiter image shows the Sundman craters. The high resolution LROC images of the LADEE impact site easily fit within the red circle (2 km dia.) on “Sundman V” eastern rim. (Photo Credit: NASA, Illus. T.Reyes)
The discovery so close to the predicted impact site confirmed how accurately the LADEE team could model the chaotic orbits around the Moon – at least during short intervals of time. Gravitationally, the Moon is truly like Swiss cheese. The effects of upwelling magma during its creation, the effects of the Earth’s tidal forces, and all the billions of asteroid impacts created a very chaotic gravitational field. Where the lunar surface is higher or more dense, gravity is stronger and vice-versa. LADEE struggled to maintain an orbit that would not run into the Moon. Without a constant vigil by Ames engineers, LADEE’s orbit would be shifted and rotated relative to the Moon’s surface until it eventually would intersect the Lunar surface – run into the Moon. Eventually, this had to happen as LADEE ran out of propulsion fuel.
The blink comparator used by Clyde Tombaugh at Lowell Observatory to discover Pluto in 1930. The basic approach has since been translated into computer software capable of searching many times faster than a human. (Photo Credit: MWT Associates/Melitatrips)
The method used by the LROC team in its basic approach is by no means new. Clyde Tombaugh used a blink comparator to search for Planet X for several months and many frame pairs of the night sky. The comparator would essentially show one image and then a second of the same view taken a few nights apart to Clyde’s eye. Tombaugh’s eye and brain could process the two images and identify slight shifts of an object from one frame to the other. Stars are essentially fixed, don’t move but objects in our solar system do move in the night sky over hours or days. In the same way, the new software employed by LROC engineers takes two images and compares them mathematically. A human is replaced by a computer and software to weed out the slightest changes between a pair of images; images of the same area but spaced in time. Finding changes on the surface of a body such as the Moon or Mars is made especially difficult because of the slightest changes in lighting and location of the observer (the spacecraft). The new LROC software marks a new step forward in sophistication and thus has returned LADEE back to us.
The following Lunar Orbiter image from the 1960s is high contrast and reveals surface relief in much more detail. Einstein crater is clearly seen, as is Sundman with J and V satellite craters on its rim.
A NASA Lunar Orbiter image of the LADEE impact site. Einstein is actually an old low profile crater 198 km in diameter with 51 km “Einstein A” at its center. Sundman is also a low profile crater, 40 km diameter, with satellite craters J (10 km dia., southwest), V (19 km dia., southeast). (Photo Credit: NASA)
A unique view of the Moon and distant Earth from China's Chang’e-5 T1 lunar test flight. Image via CCTV News and UnmannedSpaceflight.com.
The Chinese lunar test mission Chang’e 5T1 has sent back some amazing and unique views of the Moon’s far side, with the Earth joining in for a cameo in the image above. According to the crew at UnmannedSpaceflight.com the images were taken with the spacecraft’s solar array monitoring camera.
Add this marvelous shot to previous views of the Earth and Moon together.
A closeup of Mare Marginis, a lunar sea that lies on the very edge of the lunar nearside. Credit: Xinhua News, via UnmannedSpacefight.com.
The mission launched on October 23 and is taking an eight-day roundtrip flight around the Moon and is now journeying back to Earth. The mission is a test run for Chang’e-5, China’s fourth lunar probe that aims to gather samples from the Moon’s surface, currently set for 2017. Chang’e 5T1 will return to Earth on October 31.
The test flight orbit had a perigee of 209 kilometers and reached an apogee of about 380,000 kilometers, swinging halfway around the Moon, but did not enter lunar orbit.
A view of Earth on October 24, 2014, from the Chinese Chang’e-5 T1 spacecraft. Credit: Xinhua News, via UnmannedSpaceflight.com.
Whether its asteroid prospecting, mining interests, or space tourism, a lot of industries are taking aim at space exploration. Some pioneering spirits – such as Elon Musk – even believe humanity’s survival depends on our colonizing onto other planets – such as the Moon and Mars. It’s little surprise then that lunar land peddlers have begun making deals for land on the Moon.
The Partially eclipsed Sun rising over the Vehicle Assembly Building on the Florida Space Coast on November 3rd, 2013.
Get those solar viewers out… the final eclipse of 2014 occurs this Thursday on October 23rd, and most of North America has a front row seat. Though this solar eclipse will be an exclusively partial one as the Moon takes a ‘bite’ out the disk of the Sun, such an event is always fascinating to witness. And for viewers across the central U.S. and Canada, it will also provide the chance to photograph the setting crescent Sun along with foreground objects.
A map showing the eclipse prospects over the CONUS. (click to enlarge). Credit: Michael Zeiler @EclipseMaps, www.thegreatamericaneclipse.com.
The shadow or ‘antumbra’ of the Moon just misses northern limb of the Earth on October 23rd, resulting in a solar eclipse that reaches a maximum of 81% partial as seen from the high Canadian Arctic. The eclipse would be annular in any event had the Moon’s shadow touched down on Earth’s surface, as the Moon just passed apogee on October 18th. The penumbral cone of the Moon’s shadow touches down at 19:38 UT in the Bering Sea just west of the International Date Line before racing eastward across North America to depart the Earth over southern Texas at 23:52 UT.
An animated .gif of this week’s partial solar eclipse. Credit: NASA/GSFC/A.T. Sinclair.
The farther northwest you are, the greater the eclipse: For example, Anchorage and Seattle will see 54.8% and 54.5% of the Sun obscured by the Moon, while Mexico City and Phoenix, Arizona will see 4.8% and 33% of the Sun’s disk obscured.
A key region will be the zone of longitude running a few hundred miles east and to the west of Ontario, the Great Lakes and the Mississippi River, which will see the Sun setting during greatest eclipse.
Simulated views of the October 23rd partial solar eclipse from around North America. Created using Stellarium.
Successful sunset viewing of the eclipse will call for a clear, uncluttered western horizon. As of 48+ hours out, the current weather prospects call for clear skies across most of the U.S. on Thursday, with the exception of the U.S. northwest… but you only need a gap in the clouds to observe an eclipse!
Predicted cloud cover for the CONUS hours prior to the start of the Oct 23 partial solar eclipse. Credit: NWS/NOAA.
It’s also worth noting that massive sunspot region AR 2192 is currently turned Earthward and will make for a very active and photogenic Sun during Thursday’s eclipse.
Sunspot activity leading up to this week’s eclipse. Credit: NASA/SDO/HMI
Proper safety precautions must be taken while observing the Sun through all stages of a partial solar eclipse. Don’t end up like 19th century psychologist Gustav Fechner, who blinded himself staring at the Sun! With the recent interest in the event, we’ve been fielding lots of questions on eclipse imaging, which presents safety challenges of its own.
An homemade solar optical filter using Baader film. Credit: Eric Teske/Stellar Neophyte.
Imaging the Sun with a solar filter is pretty straightforward. Glass solar filters for telescopes fitting over the full aperture of the instrument can be had from Orion for about $100 USD, and we’ve made inexpensive filter masks out of Baader AstroSolar Safety Film for everything from binoculars to DLSR cameras to telescopes. Make sure these fit snugly in place, and inspect them for pin holes prior to use. Also, be sure to cover or remove any finderscopes as well. And throw away those old screw-on eyepiece filters sold by some department store scope manufacturers in the 60s and 70s, as they can overheat and crack!
Catching the eclipsed Sun with a silhouetted foreground requires more practice. We’ve had great luck using a DSLR and a neutral density filter to take the f-stop and glare down while preserving the foreground view. Remember, though, an ND filter is for photographic use only… never stare at the Sun through one! Likewise, you’ll need to physically block off your camera’s viewfinder to resist the same temptation of looking while aiming. Shooting several quick frames at 1/1000th of a second or faster will help get the ISO/f-stop settings for the local illumination just right. Even 1% sunlight is surprisingly bright, as we noticed observing the May 10th 1994 annular eclipse from the shores of Lake Erie.
You’ll also need a lens with a focal length of 200mm or better to have the Sun appear larger than a dot in your images. Several key landmarks, such as the Saint Louis Arch and the Sears Tower in Chicago lie along the key sunset zone Thursday and would make great potential foreground shots… our top pick would be the 1978 World’s Fair Sunsphere Tower in Knoxville, Tennessee for a photo with a true visual double entendre. Scout out the geometry of such a shot the evening beforehand, and remember that you’ll need a good amount of distance (half a mile or more) for a building or foreground object to appear equal in size to the Sun.
And don’t miss the spectacle going on around you during an eclipse as well. Projecting the disk of the Sun using a pinhole camera or binoculars onto a piece of paper makes for a great shot. Hundreds of crescents may litter the ground, caused by natural “pinhole projectors” such as gaps in leaves or latticework. And photographs of everyday folks wearing eclipse glasses standing enthralled by the ongoing event can be just as captivating as the eclipse itself.
Imaging a partial solar eclipse via a homemade shoebox binocular projector. Photo by author.
Up for a challenge? Another unique opportunity awaits eclipse viewers in the northwest, as the International Space Station will cross the disk of the Sun around ~21:08 UT during the eclipse. You’ll need to run video to catch such a speedy (about a second in duration) event, but it would make for a great capture! Be sure to check CALSky for predictions of ISS solar and lunar transits within 48 hours of the event.
The path of the ISS over the US during the partial eclipse. Credit: Orbitron.
Robotic eyes in low Earth orbit will be watching the eclipse as well. JAXA’s Hinode and ESA’s Proba-2 routinely observe the Sun and will catch fleeting eclipses on successive passes on Thursday… in the case of Hinode, it may score a direct “hit” with an annular eclipse seen from space around 21:03 UT:
And don’t forget, we’re now less than three years out from the next total solar eclipse to (finally!) grace the United States from coast to coast on August 21st, 2017. This week’s partial solar eclipse offers a great test run to hone your photographic technique!
Near-infrared image of the Moon's surface by NASA's Moon Mineralogy Mapper on the Indian Space Research Organization's Chandrayaan-1 mission. The mapper helped identify water- and hydroxyl-rich areas on the lunar surface.
Image credit: ISRO/NASA/JPL-Caltech/Brown Univ./USGS
When they first set foot on the Moon, the Apollo 11 astronauts painted a picture of the landscape as a bone-dry desert. So astronomers were naturally surprised when in 2009, three probes showed that a lot of water is locked up in minerals in the soil. There has been some debate as to where the water came from, but now two researchers with the National Museum of Natural History in Paris, France, have determined that most of the water in the soil on the surface of the Moon was formed due to protons in the solar wind colliding with oxygen in lunar dust, rather than from comet or meteorite impacts.
The first hints that there was water on the Moon came when India’s Chandrayaan-1 found hints of water across the lunar surface when it measured a dip in reflected sunlight at a wavelength absorbed only by water and hydroxyl, a molecule that contains one atom of hydrogen and one atom of oxygen.
The partially eclipsed sun sets over Island Lake north of Duluth, Minn. on May 20, 2012. Credit: Jim Schaff
2014 – a year rich in eclipses. The Moon dutifully slid into Earth’s shadow in April and October gifting us with two total lunars. Now it’s the Sun’s turn. This Thursday October 23 skywatchers across much of the North America and Mexico will witness a partial solar eclipse. From the eastern U.S. the eclipse will reach maximum around the time of sunset, making for dramatic picture-taking opportunities. Further west, the entire eclipse will occur with the sun up in the afternoon sky. Either way, you can’t go wrong.
During a solar eclipse, the orbiting Moon passes between the Sun and Earth completely blocking the Sun from view as shown here. In Thursday’s eclipse, the moon will pass a little north of a line connecting the three orbs, leaving a portion of the sun uncovered. To view a partial solar eclipse, a safe solar filter is necessary. Credit: Wikipedia
Solar eclipses occur at New Moon when the Moon passes between the Sun and the Earth and blocks the Sun from view. During a total solar eclipse, the Sun, Earth and Moon are exactly aligned and the Moon completely hides the brilliant solar disk. Partial eclipses occur when the Moon passes slight north or south of the line connecting the three bodies, leaving a slice of the Sun uncovered. For that reason, a safe solar filter is required to protect your eyes at all times. We’ll delve into that in a minute, but first let’s look at the particulars of this eclipse.
Map showing times and percentage of the sun covered during Thursday’s partial solar eclipse. Times are Pacific Daylight – add 1 hour for MDT, 2 hours for CDT and 3 hours for EDT. Interpolate between the lines to find your approximate viewing time. The arc marked A shows where the eclipse begins at sunset; B = Maximum eclipse at sunset and C = Eclipse ends at sunset. Credit: NASA, F. Espenak,with additions by Bob King
Nowhere will this eclipse be total. At best, polar bears and musk oxen in Canada’s Nunavut Territory near Prince of Wales Island will see 81% of the sun covered at sunset at maximum eclipse. Most of the rest of us will witness about half the Sun covered with the northern U.S. getting around 65% and the southern states closer to 40%. In Minneapolis, Minn. for instance, the eclipse begins at 4:23 p.m. CDT, reaches a maximum of 62% at 5:35 p.m. and continues on till sunset at 6:14 p.m. For times, coverage and other local circumstances for your town, click over to U.S. cities and cities in Canada and Mexico.
Safe solar filters come in several varieties ranging from plastic glasses to a #14 welder’s glass for visual observation and snug-fitting optical filters that fit over the end of a telescope. Credit: Bob King
There are several ways to observe a partial eclipse safely, but they all start with this credo: Never look directly at the Sun. Dangerous ultraviolet and infrared light focused on your retinas will damage your vision for life. Nothing’s worth that risk. Happily, filters and indirect viewing methods are available. Eclipse glasses fitted with mylar or polymer lenses are a great choice. I’ve used them all but my favorite’s still the classic #14 welder’s glass because it slips in the pocket easily and takes a beating. Make sure it’s a #14, not a #13 or lower.
You can mount binoculars on a tripod, cover one lens with a lenscap and project the sun’s image safely onto a sheet of white cardboard. Credit: Bob King
Telescopes should be outfitted with an optical mylar or aluminized glass solar filter that fits snugly over the top end of the tube. A welder’s glass gives a green solar image, mylar a blue one and black polymer a pale orange. Filters work by only allowing a fraction of the Sun’s light to reach the eye. At the end of this article I’ve listed several sites that sell a variety of safe solar filters for naked eye and telescopic use.
Easy guide to building a pinhole projector for solar eclipse viewing
Indirect methods for safe viewing include projecting the Sun’s image through a small telescope or pair of binoculars onto a sheet of white paper or cardboard. You can also build a pinhole projector shown in the video above. A box and piece of aluminum foil are all you need.
Tiny gaps along the length of this palm frond created a series of solar crescents during the July 1991 eclipse. Credit: Bob King
If for some reason you aren’t able to get a solar filter, all is not lost. The tiny spaces between leaves on a tree act like pinhole projectors and will cast hundreds of images of the Sun on the ground below during the eclipse. To see the effect even better, bring along a white sheet or blanket and spread it out beneath the tree. You can even cross your hands over one another at a right angle to create a pattern of small “holes” that will reveal the changing shape of the Sun as the eclipse proceeds.
The white crescents show how much of the Sun will be visible from a variety of locations at maximum eclipse. The farther north you go, the deeper the eclipse. Credit: Jay Anderson
Now that you’re rockin’ to go, here are some other cool things to look for during the eclipse:
* Sunspots appear black when viewed through a filtered telescope, but they’re no match for the opaque-black Moon silhouetted against the Sun. Compare their unequal degrees of darkness. With a little luck, the giant sunspot region 2192 will provide a striking contrast with the moon plus add interest to the eclipse. This region only recently rotated onto the Sun’s front side and will be squarely in view on Thursday.
* The moon may look smooth and round to the eye, but its circumference is bumpy with crater rims and mountain peaks. Watch for these tiny teeth to bite into the solar disk as the eclipse progresses.
* From locations where half or more the Sun’s disk is covered, look around to see if you can tell the light has changed. Does it seem somehow “grayer” than normal? Is the blueness of the sky affected?
As I learned from comet discoverer and author David Levy many years ago, every eclipse involves the alignment of four bodies: Sun, Earth, Moon and you. We wish you good weather and a wonderful eclipse, but if clouds show up, you can still watch it via live stream on SLOOH.
UPDATE: Not only will the sun be eclipsed Thursday afternoon but the planet Venus will shine just 1.1 degrees to its north. Venus is just two days from superior conjunction. In the photo, the planet is in the background well behind the Sun. Don’t count on seeing it – too close and too much dangerous glare! This photo was taken from space by NASA’s Solar and Heliospheric Observatory early Thursday Oct. 23 using a coronagraph to shade the Sun. Credit: NASA/ESA
Solar filter suppliers – for a #14 welder’s glass, check your local phone book for a welding supply shop:
* Thousand Oaks Optical — Large variety of solar filters for telescopes and cameras. Sheets of black polymer available if you want to make your own.
* Rainbow Symphony — Eclipse glasses and solar viewers as well as filters for binoculars and telescopes. The basic glasses cost less than a buck apiece, but you’ll need to buy a minimum of 25 pairs.
* Opt Corp — Offers high-quality Baader mylar optical filter material to make your own.
* Orion Telescopes — Glass and mylar filters for telescopes and binoculars.
* Amazon.com – Filters for naked eye use
A collage of moon photos that photographer David Blanchflower took between March and October 2014 from Newcastle upon Tyne, United Kingdom, using a Nikon Coolpix L810 camera. One picture used a telescope (Skywatcher Explorer 200P).
We think of the Moon as a grey and unchanging world, but throw in the effects of Earth’s atmosphere and orbit and you get some really cool effects. It can look yellow or red or almost blue. It changes from a full disc to a crescent and back again. It gets bigger and smaller as the Moon drifts forward and backward in its orbit. Sometimes it’s even eclipsed.
Remarkably, one photographer has captured many of these moods in a single collage. The picture above from David Blanchflower was recently posted to the Universe Today Flickr pool, showing images between March and October 2014.
“All from Newcastle upon Tyne with a Nikon Coolpix L810 Camera,” Blanchflower wrote. “One of the pictures was taken with the aid of a telescope (Sky-Watcher Explorer 200P). They show a variety of colours and phases.”
We’d love to see your shots of the moon as well, so please feel free to contribute to the Flickr pool. Posting a picture means we could use it in a future story.
The feature called Maskelyne is one of many newly discovered young volcanic deposits on the moon. Called irregular mare patches, these areas are thought to be remnants of small lava eruptions that occurred recently in the moon's past. To view this image correctly, the large, dark, circular feature right of center is pancake-like dome that rises ABOVE the surrounding lighter-toned terrain. Lower domes, many pitted with small craters, are seen from left to right across the photo. Credit: NASA/GSFC/Arizona State University
The Moon’s a very dusty museum where the exhibits haven’t changed much over the last 4 billion years. Or so we thought. NASA’s Lunar Reconnaissance Orbiter (LRO) has provided researchers strong evidence the Moon’s volcanic activity slowed gradually instead of stopping abruptly a billion years ago.
Some volcanic deposits are estimated to be 100 million years old, meaning the moon was spouting lava when dinosaurs of the Cretaceous era were busy swatting giant dragonflies. There are even hints of 50-million-year-old volcanism, practically yesterday by lunar standards.
Ina Caldera sits atop a low, broad volcanic dome or shield volcano, where lavas once oozed from the moon’s crust. The darker patches in the photo are blobs of older lunar crust. As in the photo of Maskelyne, they form a series of low mounds higher than the younger, jumbled terrain around them. Credit: NASA
The deposits are scattered across the Moon’s dark volcanic plains (lunar “seas”) and are characterized by a mixture of smooth, rounded, shallow mounds next to patches of rough, blocky terrain. Because of this combination of textures, the researchers refer to these unusual areas as “irregular mare patches.”
Measuring less than one-third mile (1/2 km) across, almost all are too small to see from Earth with the exception of Ina Caldera, a 2-mile-long D-shaped patch where blobs of older, crater-pitted lunar crust (darker blobs) rise some 250 feet above the younger, rubbly surface like melted cheese on pizza.
Lavas on the moon were thin and runny like this flow photographed in Kilauea, Hawaii. Credit: USGS
Ina was thought to be a one-of-a-kind until researchers from Arizona State University in Tempe and Westfälische Wilhelms-Universität Münster in Germany spotted 70 more patches in close-up photos taken by the LRO. The large number and the fact that the patches are scattered all over the nearside of the Moon means that volcanic activity was not only recent but widespread.
Astronomers estimate ages for features on the moon by counting crater numbers and sizes (the fewer seen, the younger the surface) and the steepness of the slopes running from the tops of the smoother domes to the rough terrain below (the steeper, the younger).
“Based on a technique that links such crater measurements to the ages of Apollo and Luna samples, three of the irregular mare patches are thought to be less than 100 million years old, and perhaps less than 50 million years old in the case of Ina,” according to the NASA press release.
Artist concept illustration of the internal structure of the moon. Credit: NOAJ
The young mare patches stand in stark contrast to the ancient volcanic terrain surrounding them that dates from 3.5 to 1 billion years ago.
For lava to flow you need a hot mantle, the deep layer of rock beneath the crust that extends to the Moon’s metal core. And a hot mantle means a core that’s still cranking out a lot of heat.
Scientists thought the Moon had cooled off a billion or more years ago, making recent flows all but impossible. Apparently the moon’s interior remained piping hot far longer than anyone had supposed.
“The existence and age of the irregular mare patches tell us that the lunar mantle had to remain hot enough to provide magma for the small-volume eruptions that created these unusual young features,” said Sarah Braden, a recent Arizona State University graduate and the lead author of the study.
It takes two to tango. The moon’s gravity raises a pair of watery bulges in the Earth’s oceans creating the tides, while Earth’s gravity stretches and compresses the moon to warm its interior. Illustration: Bob King
One way to keep the Moon warm is through tidal interaction with the Earth. A recent study points out that strains caused by Earth’s gravitational tug on the Moon (nearside vs. farside) heats up its interior. Could this be the source of the relatively recent lava flows?
So the pendulum swings. Prior to 1950 it was thought that lunar craters and landforms were all produced by volcanic activity. But the size and global distribution of craters – and the volcanoes required to produce them – would be impossible on a small body like the Moon. In the 1950s and beyond, astronomers came to realize through the study of nuclear bomb tests and high-velocity impact experiments that explosive impacts from asteroids large and small were responsible for the Moon’s craters.
This latest revelation gives us a more nuanced view of how volcanism may continue to play a role in the formation of lunar features.
The Lunar Reconnaissance Orbiter turned for a quick look at Earth and one of our closest planetary neighbors—Mars. Credit: NASA/GSFC/Arizona State University,
Wow, this doesn’t happen very often: Earth and Mars together in one photo. To make the image even more unique, it was taken from lunar orbit by the Lunar Reconnaissance Orbiter. This two-for-one photo was was acquired in a single shot on May 24, 2014, by the Narrow Angle Camera (NAC) on LRO as the spacecraft was turned to face the Earth, instead of its usual view of looking down at the Moon.
The LRO imaging team said seeing the planets together in one image makes the two worlds seem not so far apart, and that the Moon still might have a role to play in future exploration.
“The juxtaposition of Earth and Mars seen from the Moon is a poignant reminder that the Moon would make a convenient waypoint for explorers bound for the fourth planet and beyond!” said the LRO team on their website. “In the near-future, the Moon could serve as a test-bed for construction and resource utilization technologies. Longer-range plans may include the Moon as a resource depot or base of operations for interplanetary activities.”
Watch a video created from this image where it appears you are flying from the Earth to Mars:
The LROC team said this imaging sequence required a significant amount of planning, and that prior to the “conjunction” event, they took practice images of Mars to refine the timing and camera settings.
When the spacecraft captured this image, Earth was about 376,687 kilometers (234,062 miles) away from LRO and Mars was 112.5 million kilometers away. So, Mars was about 300 times farther from the Moon than the Earth.
The NAC is actually two cameras, and each NAC image is built from rows of pixels acquired one after another, and then the left and right images are stitched together to make a complete NAC pair. “If the spacecraft was not moving, the rows of pixels would image the same area over and over; it is the spacecraft motion, combined with fine-tuning of the camera exposure time, that enables the final image, such as this Earth-Mars view,” the LRO team explained.
Check out more about this image on the LRO website, which includes a zoomable, interactive version of the photo.
