Nature of project: data analysis, software
Available to students on full-time physics degree schemes or joint students.
Lunar impact basins are giant craters, as a rule of thumb greater than or equal to 300km in diameter. They are circular (or slightly elliptical) depressions with inner, and several outer, topographic rims. They often have radial ejecta scour marks in the topopgraphy outside their main ring and can be filled with basaltic mare lava fill. Impact basins have been found in the past by visual inspection of images (under certain equatorial illumination directions) and by studying gravity data obtained by spacecraft. However some ancient Pre-Nectarian era basins are so degraded by subsequent impacts that they may be difficult to detect with these two methods. Instead you will use NASA LRO LOLA altimeter derived digital elevation models (DEMs) to search for rings of topographic highs (these may not all be at the same height) or for large scale radial structures, either of which might point to the presence of an ancient impact basin.
A successful project will develop beyond the above in one/some of the following directions:
The work can be done by using visualisation software, supplied by your supervisor, to manually illuminate the surface from a variety of different directions (in real-life the Moon gets illuminated from a East-West direction), in order to show up rings of topographic highs. Or you can write your own code to automatically identify local topographic peaks and fit circles through them, or look for troughs in the DEMs and use the Hough transform to map out lineaments and see if these are radial to some origin.
When considering where to take your project, please bear in mind the time available. It is preferable to do fewer things well than to try many and not get conclusive results on any of them. However, sometimes it is useful to have a couple of strands of investigation in parallel to work on in case delays occur.
Additional scope or challenge if taken as a Year-4 project: 1) Compare to Gravity maps produced by the GRAIL mission
2) Check the geology present to see if there is Pre-Nectarian material where it would expect to be if the basins are Pre-Nectarian
3) See how the diameters of the basin rings found by the software for known impact basins compare with published values
Please speak to Tony Cook if you consider doing this project.
Initial literature for students:
Much of previous work has been done by visual inspection of images, or simply artifically flooding topographic lows in DEMs to find basins. Alternatively relying upon gravity data. The approach suggested here is specifically designed to look out for highly degraded ancient pre-Nectarian impact basins on the Moon.
Your supervisor will help find the data for you and give you lots of valuable pointers on how to do the work. He has discovered several previously unknown impact basins using similar techniques.
|milestone||to be completed by|
|Compiled a list of all known impact basins found by different methods - compare the dimensions of the basin rings found||Christmas|
|Fully acquainted with the visualisation software||end of February|
|Now will either have comprehensively generated lots of regional visualisations across the Moon and started listing newly suspected basins or will have software up and running to look for topographic highs and/or radial features||mid-March|
|Will have measured physical characteristics of the basins found (existing and newly discovered) and compared these to existing data||Easter|