Exploring the Moon with Moon Zoo: lunar science from public participation

Our nearest celestial neighbour still has much to tell us about the origin and evolution of the Solar System. The primary scientific importance of the Moon arises from the fact that it has an extremely ancient surface, mostly older than 3 billion years, with some areas extending almost all the way back to the origin of the Solar System 4.5 billion years ago. The lunar surface therefore preserves a geological record of the early evolution of a terrestrial planet, which more complicated bodies such as Earth, Venus and Mars have long lost. Moreover, as the Moon has been orbiting the Earth for all this time, much of this record is directly relevant to understanding the cosmic context for the earliest history of our own planet.

One of the most powerful tools currently being used in these studies is the high-resolution Lunar Reconnaissance Orbiter Camera (LROC) currently orbiting the Moon on NASA’s Lunar Reconnaissance Orbiter (LRO) spacecraft, which is able to resolve features as small as 50cm across on the surface. Our project will utilise an unprecedented new catalogue of lunar surface features imaged by LROC, and which already contains the sizes, shapes, and locations of several million craters, boulders, and volcanic landforms on the lunar surface. This unique database is being compiled by the Moon Zoo citizen science project (http://www.moonzoo.org/), which harnesses ‘crowd-sourcing’ techniques to identify lunar surface features. The aim of the project is to turn this rich, and growing, archive of observations into new knowledge of lunar and Solar System processes.

A large part of the project will involve statistical studies of the distribution of small craters (tens to hundreds of metres across) on the lunar surface. This will enable us to estimate the ages of the surfaces studied (because older surfaces accumulate more craters), and to determine the thickness of the lunar soil (‘regolith’). We will also be able to map the distribution of boulders across the lunar surface, which will enable us to produce boulder-density hazard maps for the identification of safe landing sites for future missions to the Moon. In addition, by comparing Moon Zoo images with images obtained by earlier space missions we hope to be identify changes which have occurred on the lunar surface within the last four decades; in particular, identifying the locations of recent impact craters will enable us to calculate the current impact flux rate of the Earth-Moon system, and thus assess the risk of meteorite impacts on our own planet. Last but not least, Moon Zoo users are asked to identify the location of lunar features which appear to be unusual, and we expect that important serendipitous discoveries may be made as a result.

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Left (a): The Moon Zoo website graphical user interface (GUI) used for crater identification and measurements. Here, a crater has been located and its size has been determined by dragging the orange cursor until the shaded area coincides with the crater rim. Clicking the ‘submit’ button enters the location and size of this crater into the Moon Zoo database. At right are the task options, including crater identification [top cross], unusual feature identification [exclamation mark], and options to indicate if a crater is full of boulders or not. The menu in the panel to the left of the image links to a range of educational and other activities.

Right (b): LROC image of a boulder-covered bench crater. The impact has excavated large blocks from below the regolith. This crater is 130m in diameter, so the regolith here is estimated to be less than about 13m deep. By determining the maximum size of craters in this area that have not excavated boulders the actual depth of the local regolith can be determined.

The Moon Zoo project is now poised to deliver high quality data to address key questions in lunar science, and is an excellent educational tool to help promote lunar science and exploration. To this end the Moon Zoo web interface is linked to a wide range of educational and public outreach material, and we hope that this will help engage the public in learning about the process of scientific discovery.

Dr Ian Crawford
Birkbeck, University of London

(co-applicants: Steven Bamford, University of Nottingham; Chris Lintott, University of Oxford; Katherine Joy, University College London)

Ian was awarded a Research Project Grant in November 2011; providing £142,443 over 36 months.