Search results for boulder tracks

Boulder Tracks

The Boulder Tracks thread is one of the most popular within the Moon Zoo forum and we have some amazing tracks posted there.

Boulder tracks are important to the Moon Zoo project – the following quote is from one of the Moon Zoo team members:

One of the main reasons we are asking Moon Zoo users to search for scars left behind by tumbling boulders is to help support future lunar exploration initiatives. Boulders that have rolled down hillsides from crater walls, or massifs like the Apollo 17 landing site, provide samples of geologic units that may be high up a hillside and thus difficult to access otherwise by a rover or a manned crew vehicle. If mission planning can include traverses to boulders that have rolled down hills, and we can track these boulders back up to the part of hillside from where they have originated, it provides a neat sampling strategy to accessing more geological units than would have been possible otherwise… Thus we hope to use Moon Zoo user data to produce a map of known boulder tracks (and terminal boulders) across the Moon. – Katie Joy

Recently ElisabethB (Els) posted the tracks shown below. Quite an amazing variety of track sizes and shapes! The track on the bottom appears to have mounds inside the track caused by the shape of the boulder that created the track.
Also, some of the tracks have craters overlapping them which may have been caused by the same impact. The original impact would have sent boulders bouncing and rolling along the regolith but would also have sent boulders upwards and they would have eventually fallen back and created craters.

The area where these tracks are found is Montes Alpes / Vallis Alpes.

ID: AMZ4003tvl
Latitude: 48.611°
Longitude: 1.70272°
Sun Angle: -62.71°
Scale: 0.51 meters / pixel
Zoom Level: 3


Exploding Boulders!

We are used to seeing boulder tracks on Moon Zoo and often come across (or actively go hunting for!) the boulder that caused them. Usually we find something like these large intact boulders having come to rest at the end of their tracks.

highlighted by placidstorm and kodemunkey

Moon Zoo team member Dr Anthony Cook recently sent me this picture of two boulder tracks in Schiller crater:

In this case the boulders are far from intact and appear to have “exploded” at the end of their journeys. What might have caused these boulders to fracture and fragment? One theory Tony suggested was that due to being under tension the boulders might have fractured before they rolled down the slope and that the movement further weakened them. Then over time the extreme temperature variations between lunar day and night could have fragmented the weakened rocks resulting in the appearance we see in the image.

Tony said:


I’m a bit puzzled though why the one on the top left has rock debris so far away from the centre. The boulder that looks like a skull rock on the bottom right has debris a lot closer to it, that could simply be explained by bits falling off as one would expect from the explanation above.

An alternative theory is that the boulders did roll down the hill intact, but were of sufficient size, area and age to be impacted by later meteorites, and these high velocity impacts split the rocks into many pieces. However, as Tony points out, the chances of this happening to two large rocks next to each other seem a bit remote.

Here is the NAC image M109502471L and the LROC article “A Recent Journey.”

In order to study this process in more detail we need more examples. So if you find any exploded (or partly exploded) boulders please post them on the forum here.

Ejecta Blocking Boulder

On the floor of Al-Bakri crater lies an approximately 100 foot diameter crater with a very unusual feature that may have interfered with its impact ejecta pattern.

ACT-REACT map NAC photo strip

You can see the open wedge area (no ejecta) caused from a strategically placed boulder near its rim.  Here is what Moon Zoo Team member Irene Antonenko ( IreneAnt ) has to say:

” This is really interesting because the boulder really shouldn’t affect the placement of the ejecta all that much. When the crater is being formed, ejecta is being thrown out from closer to the centre, so the boulder would be too far away to affect the ejection of material. And, when the material lands, it is thought to land from above (not sideways), so again, the boulder shouldn’t affect the emplacement of ejecta material. “

There may be some tells as one looks around the crater floor for clues that may help solve this mystery.  Our ejecta blocking boulder appears to have been sitting at that location for quite some time. There does not appear to be any boulder tracks like the one below from a boulder that probably rolled down from the rim of Al-Bakri crater south of our mystery boulder.

If you look at the other boulders in the area you will see that they appear to be white (high albedo). The ejecta blocking boulder is darker and appears to be the black sheep of the boulder community. This anomaly may be resolved if one considers that the darker color of the boulder may be due to it being covered with a dusting of fine ejecta particles from the impact.

It appears that the major force of the impact, as Irene stated above, moved up and over the boulder not affecting or having little affect on its placement. However, there does seem to be a lateral surface flow of ejecta that hit the boulder. The boulder then acted like a nozzle/guide that created the unique ejecta- free wedge design out from the crater. There is also a possibility that crater excavation moved our mystery boulder up to its present position while blocking the ejecta along the way.

The old boulder may have staked its claim to that spot first and was not willing to give it up even with the more recent arrival of a claim jumping impactor.  What are your thoughts?

Tom128 is a regular contributor on the Moon Zoo forum.

Why Study The Moon?

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.

Boulder Tracks

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!

Moon Zoo Science Goals

Here’s a reminder the Moon Zoo science goals- and what our clicks are being used for.


 Crater Survey

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.

Boulder Wars

To produce a boulder density hazard map to assist in identifying suitable landing sites for future human or robotic lunar missions.


  1. To produce peer-reviewed science.
  2. To promote lunar and planetary science through using Moon Zoo as an educational and public outreach tool.
  3. To identify small, highly elliptical craters that may have preserved meteoritic material.
  4. To assess degraded craters according to variations in user measurements and produce maps of crater degradation states.

Into the lake of death!

The ‘Lake of Death’ (Lacus Mortis) lies in the northeastern part of the Moon, north of Mare Serenitatis, and is either an ancient crater or a basin, which has been flooded by lava. It is about 150 km in diameter with the crater Burg, which was formed less than a million years ago, situated approximately in the centre. Lacus Mortis was named by selenographer Giovanni Riccioli in 1651 but he gave no reason for its strange name.

Lacus Mortis also contains one of the few “true” faults found on the Moon and you can see it (marked with an orange arrow) in the image below starting at the southern boundary of Lacus Mortis and going north before finally turning into a rille. (See the first link under Useful Links for more images of the fault).
The western half of Lacus Mortis also contains several rilles, the main one of which is Rimae Burg which is over a 100 km in length and is a graben. Where this rille crosses the boundary between Lacus Mortis and the highlands in the southwest, there are some volcanic cones – see link #4 under Useful Links for more information.



A larger image containing feature names will be found here: LROC Context Image

Burg crater, within Lacus Mortis, is worth exploring as it has many boulder tracks and some nice landslide textures on the western crater wall. See links #2 and #3 under Useful Links for more information.

Strip: M113778346LE
Boulder tracks within Burg crater

Landslide textures from inner wall of Burg crater, western side.

Useful Links

A true fault in Lacus Mortis: Lacus Mortis Fault

Boulder tracks within Burg crater: A Gathering in Lacus Mortis

Description of Burg crater: Not your average complex crater

Volcanic domes: Volcanoes in the Lake of Death

A mystery! Tidbits of Strangeness

Schiller Crater

The Image of the Week for 20th February 2012 featured exploding boulders, discovered by Dr Anthony Cook, in Schiller crater which is located in the southwestern region of the Moon, south of Oceanus Procellarum at coordinates 51.8 S / 40.0 W. This crater is interesting in its own right apart from the exploding boulders!

Schiller crater is one of the most uniquely shaped craters on the Moon and its formation is still a bit of a mystery. It is elongated as if it had been stretched lengthwise at some point but was probably created by a grazing (oblique) impact or is a secondary impact crater. At least one article claims that it was created by a multiple impact, i.e. the impacting object broke up just before hitting the Moon (see Formation of Irregular Craters on the Moon below).
The crater is approximately 180 km in length and 70 km wide.
The image below is an LROC WAC Global 100 meter mosaic draped over the laser altimetry (LOLA) digital elevation model as seen from an imaginary point 65 kilometers over the elongated crater’s southeast.

Credit: NASA/GFSC/Arizona State University

Useful Links

An interesting article about boulders and boulder tracks around the central peak complex of Schiller crater. Some worthwhile images in the article.
LROC: A Recent Journey

Geologic Studies of the Schiller-Schickard Region of the Moon – PDF

Formation of Green Coffee Cup Shaped Irregular Craters on the Moon – PDF

One Year on the Moon

This week, Moon Zoo celebrates its first year since launch back in May 2010. Initially designed as a way to count and measure craters, the simple ‘point and click’ interface was an inspired idea allowing users to mark out craters seen in high resolution images of the lunar surface.  The addition of a tool to ‘flag’ interesting features, objects and locations has provided some great discussion and superb image posts to our forum.
We’ve hunted down and rediscovered the ‘Apollo’ and ‘Lunar’ landing sites in unprecedented detail, searched for lost spacecraft debris and followed miles of boulder tracks. Our hunt for the ‘weird and wonderful’ has revealed stunning volcanic vistas, beautifully defined features and intricate crater chains.  Recent work on the forum, using new tools and techniques, has allowed us to study the lunar surface at oblique angles revealing yet more lunar mysteries and, equally, more questions.

For this special ‘Image of the Week’/Blog I have decided to take a retrospective look at the last year, recounting some of the amazing features and locations posted on the forum. I would like to post every image from our weekly slot but I’ll choose one of my personal favourites from each month.

I hope you enjoy them as much as I do.

From our first Image of the Week in May 2010 The volcanic caldera ‘Ina’.

Ina (named after a lunar goddess in Polynesian mythology) is an odd looking “D shaped” lunar geological feature about 2 kilometres wide which was first spotted by the Apollo Astronauts. (Jules)

LPOD image

Moon Zoo image

June 2010 Caro’s Tadpole.

Posted by Caro as something odd and maybe a possible crater chain, it is rich in detail and looks a little like a tadpole complete with a tail. (Thomas)

July 2010 Great Fresh Whites.

Fresh white impact craters are the most recent impacts on the Moon. Anything less than a billion years old (which means it is from the current Copernican era), is considered young in lunar terms. (Jules)

August 2010 Deep Seated Fractures.

Could they help us in the hunt for Transient Lunar Phenomena (TLP)?

September 2010 Moon Bridges

This is the King Crater Bridge from LROC image number M113168034R (Jules)

October 2010 The Aristarcus Region.

Aristarchus crater was named after the Greek astronomer Aristarchus of Samos by an Italian mapmaker called Giovanni Riccioli. The crater is relatively young, being formed approximately 450 million years ago and is one of the brightest craters on the nearside with an albedo almost double that of other similar features. (Geoff)

November 2010 Awesome Crater.

This crater was found by user mercutin and posted in the Crater Questions thread on 4th November 2010. I downloaded the LRO strip containing the crater and extracted the following image. (Geoff)

December 2010 Dark ejecta from Daguerre Crater.

A stunning picture of the dark material spreading out in a ray pattern and also cascading over the crater wall towards the crater floor. (Tom128)

January 2011 South Ray Crater

South Ray crater is about 2 million years old and the Apollo 16 astronauts returned samples from this area for analysis back on Earth. (Geoff)

An image stitched together by Moon Zoo forum member Bunny Burton Bradford

February 2011 Stratified Ejecta Blocks.

Another hunt….and this time it’s stripy! (jules)

Katie Joy from the Moon Zoo team says: We would like you to take a closer look at large boulders in Moon Zoo images. We want people to spot boulders that have layers cutting across the rock.

LROC image

Forum members Half65 and Tom128 found these examples of stratified bouders in Aristarchus.

An example posted by Geoff

March 2011 Tycho.

Appropriately named after one of the most colourful characters in astronomy, Tycho Brahe, Tycho is one of the most prominent craters on the Moon with its large, bright ray system dominating the southern hemisphere. (Jules)

credit NASA

And here’s a close up of the rugged crater floor. (Jules)

April 2011 Potential Caves and Sink Holes in Copernicus Crater.

I came across one good candidate on the floor of Copernicus Crater (JFincannon)

Moon Zoo users have now classified 2,087,029; an area of 48,348 square miles or 206.6 Chigacos within the first year. With more images to come and fresh locations to search, I look forward to another successful year of discovery and learning as we reveal more of our closest neighbour.


Have fun and happy hunting.

Moon Zoo Forum

Additional  news links:

Moon Zoo featured on BBC (at18:20 min)
From NASA JPL, Moon Zoo Telecon
From Scientific American

Thomas J is a volunteer moderator for the Moon Zoo forum.

Apollo 12 and Surveyor 3

Here is a seldom posted photograph showing Surveyor 3 from Block crater which is a small crater just inside the rim of Surveyor crater.  The Apollo 12 lunar module Intrepid, not shown, would be behind astronaut Alan Bean who took the photograph.  Notice the astronauts’ path in the regolith at top of Surveyor crater moving along the rim.  Click on NASA link below for an incredible view (click on photo to magnify).  Apollo 12 landed on the Ocean of Storms on November 19, 1969.

Below is a photograph mosaic taken by Surveyor 3 that shows Block crater right of center.  Surveyor 3 landed on April 20, 1967.  Its camera is pointed in the direction where Alan Bean would be standing and aiming his camera at Surveyor 3 two and a half years later.  Here is a contour map of Surveyor crater.

Surveyor 3 made scoop marks in the lunar regolith that were recorded with its television camera.  31 months later (see diagram of scoop marks) the Apollo 12 astronauts photographed them. and

The scoop mark in right photograph is just below the footprint.  At Moon Zoo we know that these disturbances of the regolith last a very long time and can be seen in many MZ photographs such as the landing site photograph featured later in this article.  Here is what the Apollo 12 Surface Journal says:

“Post-mission analysis indicated that, in the 31 months since Surveyor landed, no meteoritic craters larger than 1.5 mm in diameter had been created in the bottom of the footpad imprint or in the areas disturbed by the Surveyor scoop. The analysis also did not show any signs of weathering over 31 months. Erosion of features by the steady rain of small meteorites is an extremely slow process.”  You can also click here to read an analysis of Sureyor 3 material returned to Earth.

Lateral Lines in Survey Crater
The astronauts came across some very interesting lateral lines in Surveyor crater that they could not explain.  This is what they said:

133:58:51 Conrad: Oh, that is interesting! What in the hell…
133:58:52 Bean: Look at how it’s kind of made them into…Once again, it looks like something has rained on it. They’ve taken on a little…
133:58:58 Conrad: Wonder if that was from us?
133:59:00 Bean: Oh, no! I don’t think so. (Pause) Hey, you notice, there’s a general trend of lines along here from the north…that would be the northeast to the southwest. See those little lines running along through the crater here?
133:59:15 Conrad: Yeah.
133:59:16 Bean: I think I’ll take a picture of that. (Pause)

Alan Bean photographed the lateral lines below and I cropped and enlarged them to show more detail. There are several of them running along the crater and I bracketed a couple between the white lines.  Surveyor 3 scoop is shown on the left.  The dark stuff is shadow.

At the Moon Zoo Forum, we often share interesting photographs that give clues to what is happening on the lunar surface.  ElizabethB submitted this Moon Zoo photograph below. What Pete Conrad and Alan Bean may have been looking at were mini boulder tracks running through Surveyor crater.


Intrepid descending

Forum member Caro made an outstanding composite photograph from Moon Zoo Apollo 12 pics below.  Surveyor 3 is on left side of crater (large crater left in MZ composite photograph) about half way down.  You can follow the footsteps from the lunar module descent stage.  NASA LROC article, ” First Look: Apollo 12 and Surveyor 3″ with more information.

The craters seen from lunar orbit were called Snowman and used as a landing aid.  Surveyor crater was the snowman’s main body.  The photo below is what Richard Gordon saw looking through his sextant from the orbiting command module Yankee Clipper. You will need good eyes.  Luckily an annotated version was made.  This link takes you to a NASA diagram of Apollo 12 mission ground tracking of Intrepid as it makes its approach and lands near Surveyor crater.

Apollo 12 mission commander Pete Conrad was a colorful individual who left a enduring legacy at NASA.  His biography, “Rocket Man” by Nancy Conrad and Howard Klausner is well worth reading.  Alan Bean was his lunar module pilot and later became an artist.  This video is an excerpt from an an excellent documentary on the lightning strike during Apollo 12 lift off and the near abort.

I think you will enjoy Alan Bean’s art gallery of Apollo missions.  Click on the “Entrance” icon and go to the index of collections.

Tom128 is a regular contributor to the Moon Zoo Forum.

Let’s Talk Moon

People take the Moon for granted. It’s familiar. It’s always there. Since the 1950s small American and Russian spacecraft have been sent to orbit it, photograph it and crash into it. Some never made it and blew up on launch, others completely missed it and are now orbiting the Sun but some successfully orbited it or landed on it and took what were back in the day considered to be amazing images.

Luna 3 and the photos it took of the far side of the Moon in 1959 (wikipedia,

The first photos taken from the lunar surface by Luna 9 in 1966 (

Landing a spacecraft on the Moon represented a very significant achievement. It showed that it was possible to land things on the Moon, that the surface would support the weight of spacecraft and, therefore, astronauts who wouldn’t disappear into lunar quicksand. Apart from these fact finding missions people had looked through telescopes at the Moon, photographed it and sketched it for years before Neil Armstrong took one small step and actually stood on it. This and the following 5 manned missions provided a wealth of data and information which is still being studied today. So several scouting missions, 6 Apollo landing missions and nearly 400kg of lunar rock later what more could there possibly be left to learn? Plenty!

Just looking up at the Moon we can see the familiar dark and light patches so it’s easy for everyone to see that the Moon has two different kinds of terrain. Look through binoculars and we can make out some craters, bright crater rays and bumpy bits and the Moon starts looking a little more complicated. Through even a small telescope the Moon is transformed into a land of mountains, hills, deep shadowy craters some with mountains in the centre, craters within craters, dark areas and incredibly bright areas. Anyone who has done this might then wonder what the mountains and craters look like up close. Now we can find out.

Moon Zoo gives us a chance to get up close and personal with the Moon using bite sized images from the Lunar Reconnaissance Orbiter Camera. The resolution of these images is staggering. Not only can we see craters as small as 1 metre in diameter we can also see individual boulders and rocks. The media has picked up on the fact that it is now possible to identify bits of spacecraft and there are many pictures in magazines, newspapers and on the internet showing the crash sites of various American and Russian spacecraft. Most of the debris has already been found and identified but it’s fun to spot it in the Moon Zoo images too.

What is quite unexpected and sometimes takes your breath away is the sheer variety of the lunar landscape. This is where the Moon Zoo forum comes into its own. Some of the images posted on the forum are just stunning. There is everything from mountain ranges and rugged boulder strewn regions to smooth plains and picturesque valleys. We have found evidence of boulders sliding and bouncing down slopes, volcanic activity and, yes, we have found spacecraft. Every click is contributing to science. We are providing data for lunar scientists to find out more about the Moon, its geology, its past and to help pinpoint areas for future exploration.

Here are just some of our recent finds:

Ina – an unusual volcanic feature A lunar tadpole Boulders close up
. . .
Bouncing, sliding boulder tracks Apollo 17 Lunar Alpine Valley
. . .

So while you are clicking on Moon Zoo please consider contributing to the forum. That’s where you can discuss your finds, post your favourite images and learn more about the Moon. We have boards where you can post images and discuss them and we choose one each week to highlight in our Image of the Week feature. We even have a virtual cafe where you can chat and chill. Don’t let that image with a striking odd feature or the image you think one of the science team should really take a look at go unnoticed — the forum is the place to post it. That’s where the Moon Zoo science team go to look. That’s where you can learn about and discuss the science and that’s where discoveries of the strange and unusual are likely to be made. It’s a mixture of amateur clickers and lunar scientists all with one thing in common — a desire to learn more about the Moon. It’s informal, friendly, and there is no such thing as a silly question. Make one post or become a regular, it’s entirely up to you, but please come and join us — you’ll get a warm welcome!

Jules is the volunteer Moderator of the Moon Zoo Forum