A number of different robotics labs are already working on this - see the linked posts.

Sorry, but I'm not sure what is meant by "abrasive toronto"?!

Yes, indeed, gorgeous photographs of spectacular landscapes! I'll take some of the descriptions from the book: the top image is of salt caravans passing each other "in the enormous Tenere are of the Sahara. The caravan in the foreground is on its way out of the deaert, each camel loaded with 450 pounds of salt, while the one in the background is on its way to the salt mines at Bilma." The cover image is of the "Karnasai Valley, Chad. Pinnacles of sandstone rise through orange dunes a few miles from Chad's border with Libya. During the conflict between the two countries in the 1980s, the entrance to this valley was planted with landmines, which keeps people out of this remote part of the Central Sahara." The third photo is of dunes in Saudi Arabia's Empty Quarter, the great sand seas of the Rub' al Khali. Dunes come in many shapes and sizes, and these are "star" dunes,shaped by more than one dominant wind direction. The last is of the Adjder Oasis, 100 km NW of Timimoun in the Grand Erg (sand sea) of Algeria. "Each of these sand pits, surrounded by dunes, contains a family farm or garden in its hollow. Barriers of palm fronds stop blowing sand from burying these plots.. The recent introduction of electric pumps is rapidly lowering the water level by three feet per year and is endangering this centuries-old system of agriculture." Hope this helps! Go to Steinmetz's website to find many more wonderful images.

Liam - thanks for the comment and the question. However, I fear that my personal expertise in abrasives is very much limited to amateur DIY projects and the occasional rock grinding. I had a look at the site you linked to, and they certainly seem to offer a wide range of high-tech professional products; perhaps worth contacting them directly with your specific needs(although it seems that French is the default language)? I guess one of the challenges is finding a specialist company that deals with individuals versus businesses. What kind of projects are you working on?

Probably not!?

Richard - that link to the article on the CIA and Abstract Expressionism is fascinating, and something I was completely unaware of. It led me to hallucinate a traveling exhibition of NASA's Earth as Art images that would emphasize their complete lack of competition from the legacy of the USSR - an antidote to competitive barbarism. But the idea is, of course, pure fantasy - the likes of Rockefeller and his "Mummy's museum" seem to be in short supply these days.

Richard - the phase diagram approaches that I have come across address the phenomenon of jamming, a behaviour that bizarrely overlaps granular materials, glasses, and foams. I wish that my comprehension of physics was at a level that allowed me to attempt to apply my "explanatory gifts" (thank you for your generosity) to this work. However, once I am faced with "Super-Arrhenius increase of the viscosity" or "data for the colloidal glass transition that can be fit to the Vogel-Fulcher form," then to say that I am out of my depth is a gross understatement. For a resource that at least begins with an accessible introduction to the issues before becoming, at least to me, quite opaque, try http://www.physics.upenn.edu/liugroup/talks/0811.UToronto.pdf Also, by the same group headed by Liu at Penn, see http://www.physics.upenn.edu/liugroup/jamming.html I would be most interested if you would share your level of penetration of this fascinating (but challenging - even to the researchers) topic!

Fethi - thanks for the comment. Unfortunately, being a geologist, I know more about the materials than the methods - architecture and building are not my specialty. I did, however, come across this comment on the famous underground buildings elsewhere in Tunisia, at Bulla Regia: "Particularly interesting is the Bulla Regia unique site where Romans built underground rooms to protect them from the summer heat and cold of the winter. They employed hollow tubes In order to create light-weight overhead vaults (the same technique can be seen in Rome, where amphorae were often embedded into upper walls to make the load much lighter)." A little research along these lines might provide more information on the answer to your question. Michael

1. I agree - don't we have enough golf courses already? Why do we always need more???? 2. Please go ahead. 3. Oops! and many thanks for pointing this out - it's just that old habit of "finish a sentence, put in the period." Now corrected, I hope (.)

Yes, we need a real humdinger of a North Sea storm to illustrate to DT where the true megalomania lies! And I suspect that Scotland's environment laws are perfectly adequate (the proposal was originally turned down) - it's simply that good old human nature and vested interests entered the equation. And on your "unrelated" link, no, I hadn't seen this remarkable news. Another illustration of how sand can help with all kinds of clever stuff - the University of Toronto press release is at http://www.news.utoronto.ca/u-t-engineers-win-third-place-gates-foundation-toilet-challenge Thanks for the link!

I suspect that you're right, Howard - it's just that I had never seen a blue one before, nor one that has broken this perfectly!

Me too, Suvrat! A long time ago now, first of all working on Landsat images of the Basin and Range of Nevada; then comparing the Ouachita Mountains and the Makran accretionary wedge to come up with some outrageous analogue hypothesis.... We obviously feel the same way about the contributions of this program - and thanks for putting in the primary link.

Drinking beer? Surely not - geologists are a sober bunch.... Thanks for the link, which I hadn't seen (although I, too, can access only the abstract right now). Interestingly dramatic seasonality to these things. What I also wonder at is the calligraphy created by the dust devils - see also, from many examples, http://www.nasa.gov/mission_pages/MRO/multimedia/mro20080123.html, and, of course, http://throughthesandglass.typepad.com/through_the_sandglass/2010/09/its-all-about-size-martian-dust-devils.html.

Hi R and F - thanks for the comments and the ideas - and the research. I suspect that the relationship between vegetation growth and sand mobility is a complex one, a variety of the chicken and egg thing. Vegetation certainly reduces mobility, but the opposite is also true - mobile sand prevents vegetation gaining a hold. My guess is that the initial vegetation got going during a time of climate and aridity change, with perhaps sufficient rainfall during the transition to stabilise the sand and allow seeds to get a grip. If this has been a cyclical phenomenon from more to less to more arid, then the totally unvegetated periods when the sand was on the move may have been relatively short, and the grains did not have time to become appreciably rounded (it's a slow process). I can get pretty windy out there today - there were a couple of occasions on my trip that watched grains on the move, and I can verify that saltation is a global phenomenon. But I would also suggest that the total distance any individual grain travels is short, before it gets buried in a sand drift against a bush. And distance travelled is an important factor in grain rounding.

Cristy - many thanks, I'm honoured!

Mohsen - you're absolutely right, they are "miracle beasts" and have been responsible for saving countless lives around the world over the centuries. Would it be correct to say that his camels are a Bedouin's most precious possessions?

Hmm - "flirting" with camels..... Thanks for the correction - there was an original typo that I corrected - but incorrectly!

Very modest by the international arenophile standards! And I really don't know - I was trying to catch up with the un-catalogued plastic bags before I left to work take up this job, and there have been quite a few sands added by myself and my battalions of arenokleptomaniacal friends over the last eighteen months. I would guess 500+ - I'll get them all organised when I'm back in the UK, I'm sure I will....

Thanks, Richard - and I love the faked sandstorm!

Erik - thanks for the information. I've had browse around Google Earth, but with no success - it's perfectly possible to spend hours doing so, and I'm sure that a lot of people are doing exactly that (but I found all kinds of other interesting stuff!). I think the other reference must be to the oasis of Farafra - directly west of there is the Great Sand Sea and then the mountains of the Gilf Kebir, but then the desert is a huge place.

Blaize - no such thing as a dunderheaded question in my opinion (and apologies for taking a while to respond). It's a good question, and raises some points about the profound differences between the history of Mars and that of the Moon. Moon sediments contain relatively small proportions of sand (typically less than 20%) and what there is is mixed up with the predominant dust (plus lumps of rock). This is because there have never been processes on the Moon to sort the sediments into different sizes and separate them - it takes water or wind to do that. All there is on the Moon is the debris that fell back to the surface after an impact, and that debris just lay there (until the next impact). And any pile of such mixed-up sediment really doesn't tell us much about the angle of repose of any particular component, just the mixture whose behaviour is more complex than that of any one constituent. Water may only have flowed on Mars a long time ago, but it did sort things out (as the wind still does for the finer material). Hope this answers your question!

Thanks for the correction - as I said, it was just a guess. I suppose that I was confused by the reference to Wadi el Gedid (or Wadi al-Jadid), which is an alternative term for the entire New Valley Governorate that covers a huge area of southern Egypt west of the Nile. Online maps showing Wadi al-Jadid (and I double-checked quite a few, including Egyptian ones) show a point south or southwest of Mut/Kharga (the governorate capital)which must locate approximately the centre of the administrative area, not a specific wadi. Add the 100 or 200 miles descriptions, and the fact that the guy who discovered it was on an expedition, plus the limestone landscape (not, admittedly, uncommon!)and I just made a guess. This does not detract, however, from the interest and poignancy of the story. BUT, Cassandra, could you provide a non-specific description of the general area in which the plane is - you say it is not south of Mut, is it north, west.....?

Forgiven! Wish I'd thought of it.... For those readers unfamiliar with the joys of dental-filling-extracting salt water taffy, see http://en.wikipedia.org/wiki/Salt_water_taffy.

Interesting ideas, Phillip - thanks for the contribution!

Ray - thanks for continuing the conversation. And you know what? In many ways I agree with you. We seem to think that models are miniature, algorithmic, versions of reality with powers and certainty unsupported by the way they work and the assumptions that went into them. For some time, I have treasured a couple of quotations from eminent physicists, the first from Werner Heisenberg: "We have to remember that what we observe is not nature in itself, but nature exposed to our method of questioning." The second is from Per Bak: "Sometimes we feel that our modeling of the world is so good that we are seduced into believing that our computer contains a copy of the real world, so that real experiments or observations are unnecessary." There is absolutely nothing wrong with models, they are powerful tools. As long as we recognise and document their limitations and the uncertainty associated with their outputs, and don't pervert them for axe-grinding. Professionally, I am intimately familiar with dealing with uncertainty - and I find it fascinating and stimulating: a certain world would be an excrutiatingly boring place in which to live (and there, of course, thrives science). The problem comes, as you say, when that intrinsic uncertainty is ignored or manipulated in the media (largely through ignorance) and when science provides the media and the public with little help in coming to grips with it. Science becomes politicised. In my view, there is nothing intrinsically wrong with the models used by climate scientists, or the work of the IPCC. BUT the conclusions drawn from them are over-simplified, melodramatic. And yet they don't need to be. The science of atmospheric greenhouse gases is indisputable - and our pouring huge volumes of those gases into our atmosphere simply seems like a stupid (and somewhat selfish)thing to do. The exact numbers and the reliability of predictions is open to debate, but the activity is, as I said, stupid. That is not to say that I subscribe to any kind of Gaia theory - as a geologist, to think that our planet in any way "cares" about our existence, or that the planet's future depends on what we, motes of dust on its scale, do, would be nonsense. My interest in uncertainty, its key role in science, and its misrepresentation in the public domain, led me to kick off a session at a Google "unconference" a couple of years ago. You can find a post or two on this back in the archives of the blog, but the interesting point here is that, in the process of this, I got to meet Judith Curry. Judith is a serious atmospheric and climate scientist at Georgia Tech, and she shares my views on the failure of climate science to describe properly the uncertainties. As a result, she has been vilified by a signficant segment of the "climate science community" but, at the same time, commands enormous respect in other segments. She keeps a very compelling blog at Climate Etc., http://judithcurry.com/. I recommend it, and I think you would find it interesting. Judith is not a "sceptic," but she simply wants to see the science done, and described, correctly, with the conclusions properly portrayed for anyone who is interested - or should be.