This is China’s Chang’e 3 landing on the Moon over the weekend.
China has now joined the very select club of just 3 nations who have landed on the Moon and this was the first soft landing for 37 years. Just under 3 minutes in the lander rotates to begin its vertical descent onto Sinus Iridum. You can see Moon dust being blown around just before landing.
The 6 wheeled Jade Rabbit (Yutu) lunar rover has now rolled onto the surface and will soon start analysing the lunar regolith.
A big weekend for China!
Moon dust is in the news. The Lunar Atmosphere and Dust Environment Explorer (LADEE) mission currently in lunar orbitis about to begin the science phase of examining the thin lunar exosphere and looking for signs of dust fountains and the curious glow of lofted dust on the lunar horizon as reported by several Apollo astronauts.
It’s soft, sticky, scratchy stuff that has a tendency to cling to everything and was responsible for ruining several scientific experiments, causing them to overheat. A big challenge on each Apollo mission was to stop it getting it inside the lunar module. John Young (Apollo 16) thought it tasted “not half bad, ” Gene Cernan (Apollo 17) said it smelled like spent gunpowder and Jack Schmitt (Apollo 17) developed the first case of lunar moon dust “hay fever.”
Apollo missions 12, 14 and 15 left scientific experiments on the Moon (using solar cells) aimed at finding out how fast moon dust would accumulate. A build-up of moon dust blocked sunlight causing the voltage produced by the solar cells to drop. Shielded and unshielded tiny solar cells sent data back to Earth until 1977. NASA assumed the data had been lost until 40 years after the solar cells had been left on the Moon the lunar scientist who developed the experiment, Brian O’Brien, said he had backup copies and began to analyse the data.
The conclusion is that moon dust builds up faster than it should in a place with no atmosphere – just the thinnest of exospheres – at a rate of 1 millimetre every 1,000 years. Why? The strange dusty lunar exosphere holds the answer.
Over to LADEE.
Using stunning Wide Angle Camera (WAC) images the LRO team created this timelapse movie of the rotating Moon. From Earth we don’t see the Moon rotate like this because the Earth’s gravity slowed the Moon down by constantly pulling against the rotation. Eventually, after millions of years, the Moon became tidally locked and now rotates about its axis in about the same time it takes to orbit the Earth so the same face of the Moon always points towards Earth.
Enjoy this spacecraft-eye view of the Moon.
APOD videos on You Tube
If you’ve ever wondered how many clicks you and your fellow Moon Zoo explorers have accumulated there is a way to find out. Click on the MoonometerTM link on the main Moon Zoo page to find not only the number of clicks (3,603,009 at the time of writing) but what those clicks look like in terms of more familiar things, like how many Australias (0.028), how many Disneylands (635,825) or how many Armillaria Ostoyae (24,290).
Keep checking back to see the numbers increase!
Massive thanks to everyone for each and every click. That’s over 3 and a half million clicks in the name of lunar science.
The Lunar Reconnaissance Orbiter has created a WAC (Wide Angle Camera) low-Sun mosaic and turned it into this amazing anaglyph. It’s well worth a look. Dig out the red and blues and spend some time floating above the Moon. If you don’t have any 3-D glasses just follow the link in this LROC article and make yourself a pair. Click on the image to go BIG!
Apollo 7 lifts off on October 11 1967
46 years ago this week Apollo 7 carried out its successful C-type low Earth orbit mission. It was vital that this mission – essentially a test flight – was a success in order to meet President Kennedy’s timetable for landing astronauts on the Moon before the end of the ’60s.
Apollo 7 was given the same mission that Apollo 1 had been scheduled to carry out the previous year. A cabin fire which killed the crew of Apollo 1 was a tragedy which left its mark on the Apollo programme. Astronauts were grounded for 20 months while the Apollo Command Module was completely redesigned and passed all new safety tests. Apollo 7’s flight was a complete success and paved the way for the first Moon landing 9 months later.
The 11-day mission was a series of firsts. It was the first Apollo mission to carry a crew into space and the first to use the Saturn IB launch vehicle to do so. Commander Walter (Wally) Schirra was the first person to fly in space three times, being the only person to fly in all of America’s first three space programs (Mercury, Gemini and Apollo) and he was the first astronaut to suffer from a cold in space which spread quickly to the other crew members resulting in some tetchy exchanges between mission control and the crew. The mission also featured the first live TV broadcast from an American spacecraft and was the first three-person American space mission.
Apollo 7’s crew during America’s first TV broadcast from space: Commander Walter Schirra (on the right), Command Module Pilot Donn Eisele, (on the left). Lunar Module Pilot Walter Cunningham is just out of shot.
… as well as 13 other things you might not know we left on the Moon.
1. Metal soccer balls
For over 50 years we have been sending things to the Moon and leaving them there. “We” being humans of planet Earth, specifically the lunar explorers of USA, Russia, Japan, China, India and the ESA nations. In 1959 the first man-made object disturbed the Moon dust when Russia launched the magnificently steam-punked Luna 2. The equipment on board, now scattered over the impact site, included a Geiger counter, magnetometer and micrometeorite detector. But that’s not all Luna 2 had on board. It also carried several pennants bearing the Soviet hammer and sickle seal in the form of 2 small metal soccer balls, one 12 cm and one 7.5 cm in diameter. These balls were designed to explode on impact and scatter the pentagonal pennants over the lunar surface. However, Luna 2 was literally hurled at the Moon so the metal balls, and pennants with them, probably vapourised on impact.
Apart from the 6 descent modules, 6 flags, remnants of scientific packages including the still operational lunar laser ranging retro-reflector arrays, 3 lunar rovers and many footprints the Apollo astronauts also left some surprising things behind on the Moon.
2. Tiny silicon disk
The 3.5 cm silicon disk was left on the moon by the crew of Apollo 11. It contained microscopic images of good will messages from the heads of 74 nations.
3. A family photo
In 1972 at the end of the Apollo 16 mission lunar module pilot Charles Duke left a family photograph on the Moon. The photo shows Charles with his wife Dorothy and their two sons, Charles and Tom. He wrote a message on the back.
‘This is the family of Astronaut Duke from Planet Earth. Landed on the Moon, April 1972.”
4. Astronaut memorial
A small (8.5 cm high) aluminium commemorative sculpture “Fallen Astronaut” designed by Paul Van Hoeydonck was left on the Moon by the crew of Apollo 15 in 1971 along with a list of the astronauts and cosmonauts who had died in the advancement of space exploration.
Commander Dave Scott left a red Bible on the controls of the Lunar Rover. It is just visible on the panel in front of the seats. The Fallen Astronaut memorial is to the right of the rover.
6 & 7. 2 golf balls and a javelin
Alan Shepard became the first person to play golf on the Moon, using golf balls and a club he smuggled on board inside his space suit. He hit two balls just before lift-off, and drove them “miles and miles and miles”. Edgar Mitchell then made a javelin out of a lunar scoop handle and threw that.
8. 12 Hasselblad cameras
It was usual practice to leave mission cameras on the Moon and just return the film magazines but Eugene Cernan, the last human to have walked on the Moon, expressed regret at disposing of his too soon.
“I left my Hasselblad camera there with the lens pointing up at the zenith, the idea being someday someone would come back and find out how much deterioration solar cosmic radiation had on the glass. So, going up the ladder, I never took a photo of my last footstep. How dumb! Wouldn’t it have been better to take the camera with me, get the shot, take the film pack off and then (for weight restrictions) throw the camera away?”
So 12 barely used sought-after Hasselblads are up for grabs.
9&10. A falcon feather and a hammer
Apollo 15 Commander Dave Scott dropped a geological hammer and a falcon feather side by side in a demonstration of Galileo’s theory that with no air resistance both objects would fall at the same rate. The demonstration went perfectly to plan and both hammer and feather remain on the Moon.
11. A four-leaf clover
Yes, there really is a four-leaf clover on the Moon. It was put there by James Irwin as Dave Scott’s commentary in the Apollo Lunar Surface Journal confirms:
Also, with the feather up there, Jim left a four-leaf clover. He dropped it right by the feather… So we have flora and fauna.
12, 13&14. Family fingerprints, a piece of lava from Earth and a photo of a stranger
James Irwin left a number of other curiosities on the Moon: silver medallions with the fingerprints of his wife and children, a small piece of Oregan lava which was given to him by Floyd E Watson, a building inspector he met on a geology field trip and a photograph of a complete stranger with the same name. Shortly before launch James received a letter with a photograph of the sender’s father, who was also called J B Irwin. The letter described how Mr Irwin had always wanted to go to the Moon but had died before witnessing the 1969 Moon landing. James Irwin said: “I thought it would be a gracious gesture to take J B’s picture and leave it on the Moon.”
The latest man-made items to end up on the Moon were Ebb and Flow, the two twin spacecraft of NASA’s Gravity Recovery and Interior Laboratory (GRAIL) mission, when they were deliberately crashed into the Moon on 17 December 2012 after the end of their successful gravity-mapping mission.
This image from the Apollo Lunar Surface Journal shows the Apollo 12 lunar module, Intrepid, prior to descent on 19 November 1969. The two large foreground craters are Ptolemaeus and Herschel. Richard Gordon took the image from the Command Service Module, Yankee Clipper, as his colleagues aboard Intrepid, Charles “Pete” Conrad and Alan Bean prepared for the second human mission to the Moon.
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.
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.