Fancy a sci-fi film? Grab some popcorn (but not much – it’s only a short film) and make yourself comfy. (Contains violence, aliens and pointy hats.)
Galileo’s first views of the rough lunar terrain, craters and mountains provided the first clues to what it might be like to walk around on the Moon. Three centuries of refining lunar maps further piqued interest in what it might be like to travel there. Innovative film maker Georges Méliès was a prolific fantasy film-maker famed for his ground-breaking animation techniques and special effects. In 1902 he wrote, directed and starred in one of the first science fiction films Le Voyage dans la Lune (A Trip to the Moon.) It is based on two popular science fiction novels of the time: Jules Verne’s 1870 2-part story A Trip to the Moon and Around It and H. G. Wells’ 1901 novel The First Men in the Moon and was produced in both black and white and hand-coloured versions.
Méliès stars as Professor Barbenfouillis president of the Astronomer’s Club who oversees an expedition to the Moon. Even though it is just 14 minutes long at 16 frames per second (the standard frame rate at the time) it was Méliès’s longest film up to that date and cost 10,000 francs to produce. It was released to huge acclaim around the world. It made Méliès famous but not rich as his rivals, including Thomas Edison, made pirate copies of the film for distribution in America where it made huge profits for them. Méliès started his own film company in an attempt to stop piracy but he eventually went bankrupt.
The plot (from wikipedia) is as follows (spoiler alert!):
At a meeting of astronomers, their president proposes a trip to the Moon. After addressing some dissent, six brave astronomers agree to the plan. They build a space capsule in the shape of a bullet, and a huge cannon to shoot it into space. The astronomers embark and their capsule is fired from the cannon with the help of “marines”, most of whom are portrayed as a bevy of beautiful women in sailors’ outfits, while the rest are men. The Man in the Moon watches the capsule as it approaches, and it hits him in the eye.
Landing safely on the Moon, the astronomers get out of the capsule and watch the Earth rise in the distance. Exhausted by their journey, the astronomers unroll their blankets and sleep. As they sleep, a comet passes, the Big Dipper appears with human faces peering out of each star, old Saturn leans out of a window in his ringed planet, and Phoebe, goddess of the Moon, appears seated in a crescent-moon swing. Phoebe calls down a snowfall that awakens the astronomers. They seek shelter in a cavern and discover giant mushrooms. One astronomer opens his umbrella; it promptly takes root and turns into a giant mushroom itself.
At this point, a Selenite (an insectoid alien inhabitant of the Moon, named after one of the Greek moon goddesses, Selene) appears, but it is killed easily by an astronomer, as the creatures explode if they are hit with a hard force. More Selenites appear and it becomes increasingly difficult for the astronomers to destroy them as they are surrounded. The Selenites arrest the astronomers and bring them to their commander at the Selenite palace. An astronomer lifts the Chief Selenite off his throne and dashes him to the ground, exploding him.
The astronomers run back to their capsule while continuing to hit the pursuing Selenites, and five get inside. The sixth uses a rope to tip the capsule over a ledge on the Moon and into space. A Selenite tries to seize the capsule at the last minute. Astronomer, capsule, and Selenite fall through space and land in an ocean on Earth. The Selenite falls off and the capsule floats back to the surface, where they are rescued by a ship and towed ashore.
The end sequence (celebratory parade and unveiling of a commemorative statue) was lost until 2002 when a well preserved complete print was discovered in a French barn making a full restoration of the whole film possible.
Dear MoonZoo aficionados,
Our next surveying exercise will be centred on the Apollo 12 landing site.
Your previous and successful endeavour saw hundreds of thousands of craters and interesting features noted in the region of the Apollo 17 landing site in the Taurus-Littrow valley. Here we witnessed a chaotic and highly scarred terrain, squeezed between tall mountains and crossed by a deep fault (the Lee-Lincoln Scarp): a rather complex geological setting. Indeed, the landing site was selected based on its geological diversity, with the aim of collecting pre-Imbrian age highland material, mare basalts, and igneous products from potential volcanic edifices.
Now we are turning our attention to the Apollo 12 landing site, and from 9 May all the Moon Zoo images relate to this site. In November 1969 Apollo 12 landed within a vast lunar mare (lava plains) region called Oceanus Procellarum (Ocean of Storms), and in particular an area baptised as Mare Cognitum (Known Sea), so called given that it had already been visited by three unmanned lunar missions (Luna 5, USSR, Surveyor 3 and Ranger 7, US). The landing region was estimated to be younger than the Apollo 11 site based on kilometre-size craters census (2.37 times fewer craters). In the following years, returned sample analyses (i.e. Stöffler and Ryder, 2001; Barra et al., 2006) estimated ages of 3.58 ± 0.01 and 3.80 ± 0.02 Gyr (both Late Imbrian Epoch), for Apollo 11, against 3.15 ± 0.04 Gyr for Apollo 12, (Eratosthenian Period). It will be very interesting to compare these direct age estimates with your high resolution/volume crater count survey, AND also compare them with the results from the Apollo 17 blitz (samples’ age: 3.75 ± 0.01 Gyr).
Obviously, as before we are also going to harvest data generated by the Moon Zoo users regarding bouldernyness and shape of the noted craters in order to build a fuller picture of the impact record in the region. As it happens, the lunar science team based at Birkbeck/UCL, UK, has been looking at the Apollo 12 region for quite sometime, both in terms of geological mapping and analysis of returned samples. We are particularly interested in the different lava flows found in the region and the mapping of small craters; the associated boulder distribution will be employed to estimate the different ages and thickness of these lava flows. Your Moon Zoo measurements of the Apollo 12 site will therefore be greatly appreciated, and they will potentially be incorporated in future scientific publications.
So, let’s start this new and exciting journey together: I will keep you posted on both results from previous efforts (A17, etc.) and the ongoing ones. Go and explore!
Barra F., et al., 2006. 40Ar/39Ar dating of Apollo 12 regolith: Implications for the age of Copernicus and the source of nonmare materials, Geochimica et Cosmochimica Acta 70, 6016-6031.
Stöffler D. and Ryder G. 2001. Stratigraphy and isotope ages of lunar geologic units: chronological standard for the inner solar system. Space Science Reviews 96: 9-54.
The MoonZoo science team would like to extend a gigantic thank you to all 20,627 users who contributed in counting craters (and more!) relating to the Apollo 17 landing site (Taurus-Littrow)!
Let’s ponder on some astonishing numbers: to date, around 8.5 million craters in total have been marked by MoonZoo citizen scientists, with around 670,000 (~8%) relating to the A17 region (from 21 selected NAC images, Figure 1); further, 3.3% (22,063) of these craters have been classified as containing boulders and 6.9% (45,893) were found to be non-circular.
Our next step is to compare your input with the ‘expert’ count looking to validate and quantify your contributions. The ‘expert’ in question is a professional lunar scientist who has published research including the statistical occurrence of impact craters on planetary surfaces. The logical assumption is that given a more or less constant collision rate of interplanetary bodies (asteroids and comets), a surface will carry the record of impact products (craters and pits) as a function of time, i.e., from the time of resurface (maybe a lava mare flow) the scarring would be proportional to the length of exposure.
As most things in geology, this scenario is true but with caveats… : first, the resurfacing by lava flow or ejecta mantling might have only partially buried ancient craters, or, more probably, only the smaller ones, thus skewing the crater-size statistical record; crater rims erode with time, even on an airless body like the Moon, at a rate of around 0.06-1 cm per million year. This might not seem much, but in the lunar chronology scale, measured in billions of years, this factor becomes significant; in reality, the biggest source of uncertainty is represented by secondary craters: most impacts generate coherent distal ejecta that, when landed, produce smaller craters virtually indistinguishable from space-born ones. And this is fractal, i.e. scaled: big impacts will generate hundreds of smaller craters that will overlap with similar ones from nearby big impacts…
The hard reality is that there are no cast-iron methods to establish the origin of each excavation (although it has been advocated that a secondary crater might be somewhat shallower in comparison to a similarly-sized primary one). So, an ‘expert’ becomes so by developing a ‘sense’ or instinct on what ‘feels’ a statistically significant crater against one that is not. This approach is more akin to ‘artistic interpretation’ than ‘hard’ science, but qualitative investigation of certain geological features is an acceptable compromise when a physical method is either not yet available or even impossible to develop.
These considerations do not stop the development of alternative methodologies though; indeed, we are working closely with a research group at Manchester University which is building an automated pattern recognition software of circular features (and others) based on theoretical models, and actual data: ‘expert’ counts, AND MoonZoo users’ data.
Now, whatever approach brings us closer to a reliable crater counting method this cannot be easily accomplished by even a troupe of crater-counting planetary scientists: the 8.5 million craters noted by the MoonZoo community would have taken years to harvest otherwise!
So, what is going to happen now? Well, the ‘expert’ and pattern recognition software data will be compared with the MoonZoo output, uncertainties and limitations of all approaches established and, hopefully, develop a method that will represent the basis for ‘trusting blind’ the MoonZoo craters stats. In practice this will translate into something like “MoonZoo crater data are consistent with other methods for crater of sizes ‘x’ to ‘y’, in images with resolution higher than ‘z’ meters, and illumination of ‘n’ degrees or higher”.
Ultimately, the crater statistics (Cumulative Crater Frequency) plotted against known crater accumulation functions (i.e. Neukum, 1983, 2010) give us an estimate of the age of the lunar region. Using these data from landing sites allows for comparison with returned samples whose age has been established in the laboratory.
Our next journey will focus around the Apollo 12 landing site, in Mare Cognitum. The geology of this region is radically different from the Apollo 17 and it should serve as a perfect complement to our work so far. Elsewhere my colleagues will discuss and introduce the region in more detail, including ulterior scientific reasons behind the choice of this landing site.
We shall keep you informed of all further developments and new projects, and, once again, thanks for your patient and enthusiastic contribution to planetary science!
Michael G.G., Neukum G., Planetary surface dating from crater size-frequency distribution measurements: Partial resurfacing events and statistical age uncertainty, Earth and Planetary Science Letters, 2010, DOI: 10.1016/j.epsl.2009.12.041.
Neukum G., Meteoritenbombardement und Datierung planetarer Oberfl�chen. Habilitation Dissertation for Faculty Membership, Univ. of Munich, 186pp, 1983.
Over on Planet Four Talk moderator wassock found this Martian double crater in the HiRise images:
which can only have been created by 2 simultaneous impacts.
He messaged me to ask if we had found anything similar on the Moon and also sent a further image of a laboratory test of a high velocity simultaneous impact by 2 objects:
Here are some lunar doubles:
Messier A (on the left – most likely created by separate events)
None of these examples has the distinctive “equatorial” ejecta pattern of first 2 images which I have never seen on the Moon. Why might that be? Well, we know that Mars and the Moon differ geologically so maybe the type of impacted surface and bedrock plays a role. Did the impact take place when Mars was much wetter/ muddier than it is now? Mars also has a more dynamic atmosphere. Would any of these differences account for the distinctive formation of the Martian doubles and ejecta pattern? Maybe the angle and velocity of impact is relevant here too and these double craters form only from high velocity overhead impacts. Wassock says he has found more Martian examples. On a quick look at ACT-REACT quick map I can’t find any lunar equivalents. Can you?
The Lunar Reconnaissance Orbiter will soon have been orbiting the Moon for 4 years. Here’s a reminder of ten cool things it “saw” in its first year.
From NASA’s mission pages.
|The coldest place in the solar system
Astronauts first steps on the Moon
Apollo14 and the near miss of cone crater
Lukhnod 1 found
LOLA’s Lunar farside
Craters and boulders with Moon Zoo
Pits and skylights
Areas of Near Constant Sunlight at the South Pole
Kaguya – NASA
Forum regular JJ went hunting for the Japanese lunar explorer Kaguya impact site. Kaguya (or SELENE: SELenological and ENgineering Explorer) was launched 14 September 2007. Once in lunar orbit Kaguya released two smaller satellites into separate elliptical polar orbits: Okina (a relay satellite for communications) and Ouna (a Very Long Baseline Interferometry (VLBI) radio source satellite for supporting radio measurements). As well as its 2 sub-satellites Kaguya carried 13 scientific instruments including a lunar Magnetometer, a Gamma ray spectrometer, a Lunar Radar Sounder and an Earth-looking Upper Atmosphere and Plasma Imager. the mission lasted 18 months after which Kayuya was sent into a series of lunar orbits prior to a controlled impact on 10 June 2009. The impact site was conveniently in darkness at the time allowing the impact flash to be seen from Earth. Okina impacted on the far side on February 12 2009. Ouna is still in orbit.
The Kaguya mission amongst other things has improved lunar global topography maps (also used by Google to make Google Moon 3D), a detailed gravity map of the far side, and the first optical observation of the permanently shadowed interior of south pole Shackleton crater.
The Kaguya impact coordinates are well documented but we couldn’t recall seeing a high resolution view of the impact site from LRO. What JJ was looking for was a small fresh impact which would have exposed some fresh lunar regolith leaving a white scar with a blackened centre where debris may remain.
The Kaguya website gives the impact coordinates as E80.4, S65.5. Here’s the location:
This indicates an impact site on the wall of an unnamed crater near crater Gill. Part of crater Gill is top left of this image provided by ESA:
Using the ACT-REACT Quick Map tool JJ located the unnamed crater.
And found a likely impact site on the rim of a smaller crater within the unnamed crater.
And finally – a potential impact site with a centre geodetic diameter of 23m:
We think it’s definitely a contender.
Shamelessly copied from today’s LPOD (Lunar Photo of the Day), this is the Customs and Immigration form signed by Apollo 11 astronauts after returning from the Moon. Yes – even the first lunar visitors had to go through customs on the way back!
My favourite bit:
“Any other condition on board which may lead to the spread of disease:
TO BE DETERMINED”
Here’s a reminder the Moon Zoo science goals- and what our clicks are being used for.
1. To improve our knowledge of the production of small lunar craters by gathering information about their numbers and dimensions. This can be used to improve lunar maps and coordinates.
2. To calculate the age of different lunar surfaces (e.g., mare, impact melt sheets, highland crust) by comparing the number and sizes of impact craters. The more cratered a region is the older it is. Knowing the age of different surfaces allows us to build up a history of the geological processes on the Moon, in particular its temporal thermal and magmatic history. What we learn about these processes on the Moon we can then apply to other small rocky planetary bodies.
3. Results from Moon Zoo could also assist in the development of automated computer crater counting systems, and to help understand how image viewing geometries influences crater counting studies.
4. To determine variations in lunar regolith thickness by assessing the presence of boulders around crater rims.
5. To identify unique and unusual morphological features that help us to better understand the geological diversity of the Moon. Recording these featured will help to develop a database of interesting morphological features (for example, boulder tracks, fresh white and dark haloed craters, crater chains, elongate craters and pits etc) for the lunar science community to use.
To produce a boulder density hazard map to assist in identifying suitable landing sites for future human or robotic lunar missions.
- To produce peer-reviewed science.
- To promote lunar and planetary science through using Moon Zoo as an educational and public outreach tool.
- To identify small, highly elliptical craters that may have preserved meteoritic material.
- To assess degraded craters according to variations in user measurements and produce maps of crater degradation states.
This week we have a mystery from the 1950s which we may be able to help resolve.
An amateur astronomer from Oklahoma, Dr. Leon Stuart, photographed a bright flare on the surface of the Moon while tinkering with his new camera in November 1953. The flare or flash was close to the Moon’s terminator and near the centre of the Moon’s face (see following image) and lasted for approximately eight seconds. Dr. Stuart published his photograph and description of the sighting in The Strolling Astronomer newsletter in 1956. He remained convinced until the end of his life that he had seem an asteroid impact the Moon’s surface but most astronomers were skeptical and said that the flash was either a meteor burning up in the Earth’s atmosphere which just happened to appear as if it was an impact on the Moon, or it was a problem with the film in the camera.
Dr. Stuart logged the event as follows:
Made by Dr. Leon Stuart, Nov. 15, 1953 at 01:00 UT. Lasted 8 to 10 sec. Also observed visually. Star images rather steady, no extraneous lights. Exposure: 1/2 sec. on E.K. 103aF3 plate. 8 inch f/8 reflector.
Position on Lunar surface is about 10 miles S.E. of Pallas. (-0.5; +.08).
Photo from Dr. Leon Stuart
Within astronomy circles Dr. Stuart’s impact was known as Stuart’s Event and was mostly ignored until recently (2002) when two scientists took an interest in this 50-year old mystery. Dr. Bonnie J. Buratti, a scientist at NASA’s Jet Propulsion Laboratory in Pasadena, California and Lane Johnson of Pomona College, Claremont, California, researched the event and their findings included some very persuasive evidence which indicated that Stuart’s photo was indeed real and is of immense historical value.
Stuart’s remarkable photograph of the collision gave us an excellent starting point in our search, we were able to estimate the energy produced by the collision. But we calculated that any crater resulting from the collision would have been too small to be seen by even the best Earth-based telescopes, so we looked elsewhere for proof. Using Stuart’s photograph of the lunar flash, we estimated the object that hit the Moon was approximately 20 meters (65.6 feet) across, and the resulting crater would be in the range of one to two kilometers (.62 to 1.24 miles) across. We were looking for fresh craters with a non-eroded appearance. [Dr. Bonnie Buratti]
The two scientists decided to search for the crater using images taken from spacecraft orbiting the Moon. They had no luck with images from the Lunar Orbiter in 1967 but they did find a likely candidate in the images returned by the Clementine 1994 mission. It was a 1.5km wide crater with a fresh-looking layer of material surrounding the crater and the size was consistent with the energy from the observed flash.
Photo Courtesy JPL, Dr. Bonnie Buratti, Lane Johnson
At this point it appears that the mystery has been solved but there are detractors who have found images of the Buratti/Lane crater in photos taken by two ground based telescopes before 1953, which rules out that crater as having been formed by Stuart’s Event. It was also ruled out by the editors of Sky and Telescope magazine who carefully measured the image of Stuart’s Event and determined that it was centred 30km from the Clementine candidate.
Maybe the Moon Zoo users can find this elusive crater if it exists! The following image shows the general area where the flash was seen. The final link under the “References” heading below contains coordinates of where the impact may have occurred.
Unfortunately, it appears that there is not complete coverage of the area by LRO – some areas do not have NAC images so the search will be difficult.
If you do find any candidates for Stuart’s Crater please post them in the Moon Zoo forum.
A good overview of the whole story with images of the event will be found here:
Stuart’s Event, Bright Flare, November 15, 1953
The following journal contains a re-publication of the original Strolling Astronomer article by Dr. Leon Stuart (page 21)
Journal of the Association of Lunar & Planetary Observers, Vol 45 Number 2
This strange link contains more images of Stuart’s Event and also coordinates of where the impact may have occurred. Scroll down within the page and it has maps of the lunar surface with the area where the impact is suspected to have occurred highlighted.
1956 Lunar Path Light?
The Apollo Lunar Surface Journal contains hundreds of images. Dig deep and you can find some surprises. Take this secret moon base for example. Note the circular access road and the living quarters annex at 11 o’clock.
Because that’s what it is – right? Wrong! A classic case of mis-direction and jumping to (very wrong) conclusions! Far from being yet another lunar conspiracy target this is actually a photo of the Apollo 15 Command and Service Module in lunar orbit over the Sea of Serenity. It was taken from the Lunar Module just before it began landing manoeuvres. You can see half of Bessel crater on the right in the image below.
More images can be found on the Apollo 15 page. Be careful how you interpret them!