2013 was a fantastic year for Moon missions, providing a new orbiter, lander and even a rover to take a fresh look at the lunar surface and what lies below. These instruments are exploring both previously studied and completely new areas of lunar science, including a detailed in situ analysis of the chemical composition of the regolith, the characteristics and origin of the elusive lunar atmosphere, and even some experiments targeting the Earth! The next few years are also set to be some exciting ones with plenty of upcoming missions from around the world. The following is a brief overview of what the brand new lunar companions are up to, what is coming up in the near future, and how all of this could enhance our current understanding of the Earth’s natural satellite.
As you’ve probably heard, China recently launched their Chang’e 3 mission in December 2013, which safely landed on the Moon and immediately deployed its Jade Rabbit rover to begin exploring the surface. Just a few of months prior to this, in September, NASA sent its Lunar Atmosphere and Dust Environment Explorer (LADEE) mission, which is currently in orbit collecting data. These two missions joined three other operational lunar satellites: ex-Earth satellites ARTEMIS P1 + P2, and the Lunar Reconnaissance Orbiter (LRO) which supplies Moon Zoo with all its high resolution images.
LADEE represents the fifth NASA mission to the Moon since 2009 and is after some interesting new data regarding the tenuous lunar atmosphere. The role of dust transport through the Moon’s exosphere is still very poorly understood, so this satellite is designed to study the process in detail as well as analyse general atmospheric properties. The payload contains a UV and visible spectrometer to study the composition of dust grains, a neutral mass spectrometer to search for noble gases present, and a lunar dust experiment to measure grain impacts at different altitudes. Interestingly, the module also carries a laser communication experiment, which is investigating the viability of using lasers to beam back data to Earth. This technology could be incredibly valuable for future missions farther into space as high volumes of data can be transmitted more efficiently than using radio waves.
So far the mission has already detected atmospheric helium, sodium, neon, potassium and argon-40, as well as confirming a lunar dust exosphere which before was only predicted. The instrument, orbiting between 20 and 150 km, has detected very few dust grains at high altitudes, but this value significantly increased as it descended. LADEE has also measured a few bursts of dust, which are thought to be a consequence of flying through ejecta caused from the impacts of nearby meteorites into the lunar regolith.
Just a few months into LADEE’s mission, the Chinese landed their first craft on another planetary body. The touchdown of Chang’e 3 came more than 40 years after the US sent the first astronauts to walk upon the lunar surface; nonetheless, this does not diminish the mission’s significance at all. The craft, testing out some really exciting new technology and equipment, will be transferring its findings to manned or unmanned missions in the future, heading for the Moon, Mercury or Mars!
The primary mission objective of Chang’e 3 is to analyse the lunar soil composition in situ in much more detail than previously achieved. Its rover, Yutu, or ‘Jade Rabbit’ in English, thus aims to further our understanding of the Moon’s – and in turn the Earth’s – history. At just 1.5 m across, Jade Rabbit carries ground-penetrating radar, cameras, a telescope and spectroscopic instruments to help achieve this goal.
Chang’e 3’s landing destination on the north edge of Mare Imbrium is a different site to those previously visited by the US and USSR missions, with emphasis on how the surface and sub-surface vary from one location to another. Over the course of the mission, it is likely that Moon Zoo will also begin a survey of this area using LRO data, so that participants can help build up a more comprehensive understanding of the site.
Alongside analysing the concentration of elements such as titanium, aluminium, iron, potassium and sodium in the surface materials, there will also be a focus on non-geology related science experiments. On the static landing module one investigation will use an extreme UV camera to monitor the structure and dynamics of Earth’s plamasphere, a region of dense, cold, highly ionized particles surrounding the Earth. A near-UV telescope will also observe stars and galaxies outside the Earth’s opaque (at these wavelengths) atmosphere. As the Moon provides a platform for long, uninterrupted observations, this experiment might inform us whether it can be used for future imaging any more effectively than a telescope in orbital space.
So, these are the data the current instruments are after, but what else do the next few years have in store? Well, in late 2014 NASA’s Orion spacecraft is heading for a flight test to orbit around the Earth with a manned crew. This will be the farthest distance from Earth astronauts have flown since the Apollo 17 mission in 1972. Also due to launch in the next few years are the Chandrayaan-2 orbiter and lander, which will mark India’s second lunar exploration mission and first touchdown. However, originally scheduled for 2015, it was revealed last week to be postponed until 2016-2017.
In fact, it’s probable that the next set of missions to the Moon will not be coming from nation states, but from private companies competing for the Google Lunar XPRIZE (GLXP). The competition, announced in 2007, has opened up a global space race with a first prize award of $20 million. The second craft to reach the Moon will receive a prize of $5 million, and an extra $5 million is on offer in bonuses to any team that achieves certain goals first. The aim of the GLXP is to inspire and encourage humanity to accomplish significant exploration feats and, in doing so, demonstrate that we are within an age where space exploration is not a monopoly of national governments.
With teams in the running from all over the globe it’s hard to tell where the fourth lunar rover will originate from. However, with a closing date of December 31st 2015 and 18 entrants still in the running, I think it is safe to expect a number of exciting new lunar launches in the next couple of years!
The Moon is seriously old and our objective here at Moon Zoo is to study its surface with the time and detail that cannot be afforded by a small team of scientists. Earth’s closest neighbour and only natural satellite represents the largest and brightest object in the sky second to the Sun, and plays a crucial physical role to life here on Earth. But as the only other body to have been walked upon by man, what do we actually know about the Moon? Why is it so important to continue to study? And what can Moon Zoo’s 47,000 participants do to help?
One of the main focusses at Moon Zoo is to examine the distribution of craters in various regions in terms of their size and frequency. By determining this relationship, we can then independently estimate surface ages of different areas that have been examined by the community. Discerning these surface ages is key to understanding the history of the early Solar System, as the Moon is thought to have formed just 30-50 million years after its birth 4.5 billion years ago. The colossal impact of the Mars-sized body, Theia, into the early Earth stripped the outermost layer of our planet and returned it to a molten state, whilst the ejecta was captured in orbit and accreted to form the Moon. Although not perfect, this hypothesis explains the relatively small size of the Moon’s core and overall lower density, since it coalesced mostly from lighter crustal material. Whilst the Moon’s internal structure is differentiated into a core, mantle and crust in a similar way to the Earth’s, its rapid cooling saw tectonic and volcanic activity cease around 3.5 billion years ago. The combination of the Moon’s inactive geology and highly tenuous atmosphere has enabled its surface to become one of the most ancient, and well-preserved in the Solar System. From this almost perfectly kept record, we are not only able to look into the Moon’s past, but also unravel some of the mysteries surrounding the Earth’s history, the early Sun, and previous Solar System environments.
On Earth, tectonic, volcanic, and weathering activity has destroyed much of its early record, which is why we look to the Moon to understand our own history. We use observations of different surface features and lunar samples to date particular regions, which can help indicate events that occurred in the inner Solar System. This can, for example, be used to date periods of heavy bombardment from asteroids, which enables us to investigate the frequency of such events in Earth’s history. The samples obtained from the Moon originate from its outermost layer, known as the regolith, which is comprised of fine dust formed by impact processes. The Moon’s practically vacuous atmosphere does little to interfere with this layer, so it is able to preserve the impact fragments and provide insight into the composition and origin of colliding bodies. The regolith also incorporates particles from the solar wind, which allows us to examine how the Sun has changed over its lifetime.
Moon Zoo is helping to uncover the lunar geological evolution by analysing high-resolution images from NASA’s Lunar Reconnaissance Orbiter (LRO), in order to expand our knowledge of past impact, tectonic and volcanic activity on the Moon. Alongside crater counting, the other current primary focus is the identification of boulders, which can indicate depth of unconsolidated material. Another outcome of this search will be the production of boulder-density maps, which can be used for future lunar missions to indicate safe (or very hazardous!) landing sites.
To date, the Moon Zoo community has already made over 3.5 million visual classifications with images from LRO, alongside many unusual geological features; the project has also been very successful in identifying spacecraft debris, rover tracks and even astronaut footprints! Data already gathered from the work of Moon Zoo participants on the Apollo 17 landing site are well on their way to producing the first comprehensive paper showing these results, which is scheduled for submission shortly. The current Apollo 12 landing site has also received a great deal of interest and will soon be drawing to a close for full analyses by the Moon Zoo science team. The next step will be analysing an entirely new data set, which will most likely delve into the rare maria on the more mysterious dark side of the Moon.
There is still a great deal more to understand about our planet’s closest relative and the clues it holds to the history of the bodies around it. Until the next stage of the project is launched, we implore you to keep clicking and help demonstrate the strong impact of citizen science on lunar research!
A puzzle for you this week. Can you tell the difference between a moon, a planet and minor planet? Below are images of craters on our Moon, Vesta and Mercury but which is which? Superficially very similar but there are differences. Click on the letters below for links to reveal the answers.
Don’t peek until you have had a guess!
How the voting went:
Picture 1 is Mercury 15.6%
Picture 2 is the Moon 15.6%
Picture 1 is the Moon 34.4%
Picture 2 is Mercury 34.4%
So how did you do? As you can see most people got this wrong! I managed to find a region of the Moon that didn’t look too obviously Moon-like so don’t feel too bad if you got them the wrong way round. The coordinates are the same for both Mercury and the Moon at lat –45 : long 125. This takes us to the lunar region around Planck and Van der Waals craters on the far side which looks very much like Mercury. At first glance the two bodies do look very similar but there are some differences – though not all obvious from the two pictures.
- Mercury has more intercrater plains (its oldest surface) than the Moon.
- Ejecta deposits and secondary craters are less extensive on Mercury due to its higher gravity field. The region of Mercury chosen is atypical in this respect though there are some clues.
- There are more tectonic features on Mercury than on the Moon (rupes, ridges, troughs etc). The lunar region I chose highlights some lesser-known tectonic features.
- The Moon (particularly the nearside has expanses of bright highland terrain and dark basaltic maria. Mercury does not, though it does have splashes of bright relatively fresh craters against the darker terrain and in this respect has more in common with the lunar far side.
- Mercury has a magnetic field indicating it still has a molten core whereas the Moon has pockets of magnetism but no global magnetic field.
Well done to those who got it right. It wasn’t easy!
So after all the clicking on Moon Zoo you should know what the lunar surface looks like! But do you? Are you a true lunarphile? Like the Moon, Mercury is also rocky and heavily cratered. Can you spot the difference?
Study the two pictures below and decide which shows lunar craters and which shows craters on Mercury. You can vote on the Moon Zoo forum.
Voting ends Sunday 16 October. Answer next week!
A recent discussion started by our science lead, AstroStu, about photographing the Moon for an entire lunar month, lead me to wonder how this would look as an animation; showing the full cycle of lunar nutation and libration. Also, last month we celebrated our first year of Moon Zoo.
With these two things in mind I found something which I find topical in respect of both lunar cycles and 365 days of the Moon. The following link will take you an animation created by the Goddard Space Flight Center Scientific Visualization Studio. It uses data from the LRO to show ‘One Year of the Moon in 2.5 Minutes’.
As you will read in the accompanying text, the Lunar Orbiter Laser Altimeter (LOLA) has already taken more than 10 times as many elevation measurements as all previous missions combined, thus giving us the global elevation map and the dramatic shadows seen in this animation.
Here is the link to the official NASA page.
I recommend full screen and some moody music for this one.
Thomas J is a volunteer moderator for the Moon Zoo forum
The new iMoon 2 – now 33% thinner and up to 15% lighter….
The iMoon 2 (pronounced /aɪmoon/, EYE-moon) is the latest in a line of natural satellites designed, developed and marketed by Apple Inc. primarily as a platform for visual observation and occasional visits. Its mean radius falls between Io and Europa. The iMoon runs the same synchronous rotation operating system as the iCharon and iGanymede. Without modification, and with the exception of Earth, it will only orbit planets approved by Apple and distributed via its online store.
Like iGanymede and iCharon the iMoon is controlled by tidal forces –a departure from most previous moons which used a destabilised asteroid orbit-triggered capture method as well as a virtual onscreen heavy bombardment in lieu of a physical impact.
The iMoon uses an LRO data connection allowing browsing on the Internet, loading and streaming of media, and installation of software. Some models also have a 0.167G wireless data connection which can connect to LROC data networks. The device is managed and synced on a personal computer via a very, very long USB cable. The new iMoon has an external magnetic field of the order of 1 to a 100 nanoteslas. It does not currently have a global dipolar magnetic field. Future iMoon upgrades will come with a liquid metal core geodynamo.
The iMoon 2 – order yours today. Please allow 27.3 days for delivery.
One thing that I have learned here at Moon Zoo as a full member-newbie is that when considering the lunar landscape what is dark may not be black and what is light may not be white. A case in point is this photograph that stumped me shortly upon arrival at Moon Zoo.
Luckily, Forum moderator Thomas J introduced me to a term called albedo. He said:
“There are a number of reasons for this change in shade. The reflectivity of the surface material is known as its albedo; material that is highly reflective will have a higher albedo than that which is not as reflective. In some situations certain areas may display high albedo material due to geological activity such as impact effects, volcanic effects and even Moon quakes. It is, therefore, not uncommon to see two contrasting shades in adjacent regions. Also, the Moon’s surface is not flat, the topography rises and falls with slopes, hills and mountains. When the Sun is low in the sky a slight slope downward can leave an area in shade. So, in this image it may be that the material on the right has a higher albedo, or it may be a downward slope on the ground level to the left with a rise to that on the right.”
Why do the tracks of the astronauts on the lunar surface appear darker than the surrounding area? One answer from spacefellowship.com is:
” This effect is most likely due to compaction of a very loose surface powder by simply walking around. The more walking in a given area, the more compaction that takes place, and thus the lower the albedo.”
We know certain areas of the lunar surface have coloration due to crater impacts and lava flows such as the famous orange soil of Apollo 17 near Shorty Crater but generally the lunar landscape was described by the Apollo astronauts as concrete, mouse grey and/or light brown in color.
This brings me to the Apollo 12 lunar sample 12047,6 that is now on loan from NASA to the Seattle Museum of Flight.
Apollo 12 astronauts Pete Conrad and Alan Bean collected this specimen while at the mare region called Ocean of Storms. It is an Ilmenite Basalt sample. From the black and white photograph you can tell that it is a concrete like color not unlike many of the photographs we view here at Moon Zoo. What is interesting is that there is more to this specimen than what you see here and read about in the paper linked to above and that is the albedo effect and color change.
I happen to be lucky and live about 15 miles from the Seattle Museum of Flight. However, it was not until I viewed an online photograph of NASA 12047,6 taken by an amateur photographer visiting the museum that I found out that the sample was on display there. On my first visit I was perplexed as the sample did not look quite like the beautiful one in the photograph but more like the concrete colored black and white photograph, though not quite as drab looking. For a month or so this mystery nagged on me and I went so far as to question the on site guides about the authenticity of the display item. Maybe it was another sample or a copy. However, I was told that it is a genuine lunar sample.
Searching the internet I found reference to color change on the lunar surface:
“The orbiting Apollo astronauts noticed a peculiar phenomenon when they observed the lunar surface at a small angle related to the sun’s light. At such small angle, the lunar surface appeared warm brown colored.”
Yes, the light bulb went on in my head and I returned to the museum several months later. When moving as close to the display case as possible and viewing the lunar rock at a sharp angle, the brown color showed up. So, here is a photograph of NASA 12047,6 taken at the Seattle Museum of Flight by amateur photographer Svacher. Just as the astronauts did, we can see the brown color of the lunar surface when the sun or in this case the viewer is correctly positioned.
Here’s some more related reading:
And thanks to Moon Zoo Team member Katie Joy for providing the following additional information and links:
Lunar Sample Atlas
Katie says: “Thin or polished samples of lunar rock can be quite pretty. Some have hints of orange (glass), others bright green (the mineral olivine), some pink (the mineral spinel.) When you view them under the microscope using polarized light rather than direct light then all the minerals appear as a really bright range of colours and look like a stain glass window.”
A Final Thought:
Being one of many amateur scientists here at MZ, the notion of albedo and color change as it applies to larger natural occurring and unaltered geology samples comes to mind such as the Apollo 12 lunar sample above. Here the surface of the sample is in its natural state showing the color change in the visible light spectrum similar to what the Apollo astronauts would have seen in similar lighting conditions.
Analyzing existing samples at the Johnson Space Center in their natural-unaltered state (if not already performed) while replicating the effect of a lunar sun at all possible angles may provide valuable information about the lunar landscape – a more holistic perspective. It may also give clues to color change of lunar formations helping to explain some anomalies associated with transient lunar phenomena.
Mapping color change of the lunar landscape at specific areas may be a helpful tool to acclimate astronauts as they once again walk on the Moon.
Tom128 is a Moon Zoo participant and a regular contributor to the Forum.
Dark haloed craters are windows to the volcanic history of the Moon. This blog entry was inspired by Thomas’s choice of Image of the Week where he highlights impact craters that have dark material surrounding the crater hole itself.
Dark haloed craters provide us with key insights into what must have been a dramatic and violent volcanic period of lunar history. To probe a little further here is a little background about eruptive volcanism on the Moon:
Between about 4 billion years ago and 3 billion years ago the lunar mantle underwent a period of partial melting where magma was generated at depth and then propagated up through fracture networks and magma conduits towards the lunar surface. It has been proposed that some of this lava was very rich in gases like carbon monoxide that may have caused rapid upward movement (maybe on the scale of one to several days) and caused dramatic pyroclastic eruptions at the lunar surface. These fire-fountaining events are similar to, but on a much larger scale than, eruptions witnessed at volcanoes in Hawaii, with some plumes of lava being thrown up to 40 km in height above the surface of Moon!
Other lavas that were less gas-rich would have migrated to the lunar surface more slowly, and could have erupted more gently, forming long lava flows that travelled great distances from their volcanic vent site. These lava flows are thought to have the consistency of runny motor oil and easily flowed into topographic lows like impact craters. Sometimes large quantities of lava must have flowed in channel networks – forming rivers of fire across the lunar surface. It must have been a dramatic time, but as available heat sources were diminished in the lunar interior, less magma was generated and by about 1 billion years ago we believe the Moon’s eruptive volcanic history came to a close.
So how do dark haloed craters fit into this story? Well they actually help address two separate lunar science questions as there are two types of dark haloed craters to keep an eye out for in Moon Zoo images (although we would please like you to classify them using the same button!)…
1. Volcanic eruption sites – these are rare places where pyroclastic beads, the ‘airfall’ deposits of lunar volcanoes, are concentrated on the lunar surface and form mantles around their source vents. These beads are a little bit like the volcanic ash or the Pele’s tears glass that gets erupted from volcanoes on Earth and you can read more about these types of dark halo mantles at:
- Explosive Volcanic Eruptions on the Moon.
- The Pyroclastic Volcanism Project at the US Geological Survey.
- Moon Zoo Thomas’s guide to pyroclastic craters.
- Pyroclastic bead features seen in LROC NAC images.
2. Crater excavation sites – you are far more likely to spot these types of dark haloed craters in Moon Zoo images. The dark haloed craters provide us with a neat view down through a series of geological layers. These are formed when an asteroid or comets smashes into the Moon, punches through an overlying light coloured layer (probably an ejecta blanket material from a nearby highland impact crater) and excavates material from below that is darker in colour. This darker material is likely to be a lava flow that was buried at depth and that is now revealed by the impact cratering process.
Here’s a nice diagram of this process can be seen at where the lower image shows a schematic of what two dark haloed impact craters look like from side-on. You can also view a 3D perspective of this process.
We call these types of buried lava flows cryptomaria as they would otherwise be hidden from view if we had not have spotted the tell tale signs of dark haloed craters. By mapping the location and extent of dark haloed craters we can therefore map out the distribution of buried lava flows at depth across the Moon and get a much better idea of the amount of ancient volcanism on the Moon. This in turn helps to shed new light on the Moon’s thermal and magmatic history, helping us to understand geological processes on small rocky planetary bodies.
Good examples of these types of impact formed dark-haloed craters spotted by Moon Zoo users include:
- http://www.moonzoo.org/examine/AMZ100185s (top right)
- http://forum.moonzoo.org/index.php?topic=209.msg4111#msg4111 (lovely collection of small craters at left centre)
- http://forum.moonzoo.org/index.php?topic=209.msg4270#msg4270 (right centre)
- Other good examples are provided on the Moon Zoo How to Take Part Tutorial.
So please do keep an eye our dark haloed craters on your Moon Zoo lunar exploring! Thanks to Irene Antonenko for providing helpful guidance about this topic.