Listening to a recent Scientific American podcast on my way into work this morning I stumbled upon an item about a project called Galaxy Zoo. This is an internet-based science project that anyone can sign up to help with in which “citizen scientists” (ordinary people) look at pictures of galaxies and classify them by following a sequence of simple questions. This is a highly efficient way of sifting through the mass of galaxy images captured by space telescpes so that scientists can then focus in on particular types of galaxies that they are interested in. It is a good approach because the human brain is really good at visual processing and can perform the classification task more reliably that a computer algorithm. So, if you fancy a bit of star-gazing you can sign up at the Galaxy Zoo website and join in.
Down down, deeper and down
There’s a report on the BBC website about a new robotic submarine that is currently undergoing final preparations ahead of an attempted dive to the deepest part of the world’s oceans, The Challenger Deep in the Mariana Trench (~11,000 metres down). This depth is deeper than Mount Everest is high (incidentally, did you know that George Everest’s name was actually pronounced Eve-Rest rather than the Ever-Est that we now use to describe the mountain that was named after him?). The robotic submarine has been developed by scientists and engineers at the Woods Hole Oceanographic Institution in the USA and is named Nereus (after the son of Pontus [the sea] and Gaia [the Earth] in Greek mythology). Challenger Deep has previously been visited only twice before, both times by human-operated vehicles, so there is plenty of potential for Nereus to turn up some interesting information. The Challenger Deep is part of a major subduction zone in the western Pacific in which oceanic crust that forms the base of the Pacific Ocean is forced down and underneath the oceanic crust that neighbours the Asian landmass and for this reason it is a major earthquake region. At this kind of depth the pressure experienced due to the weight of water supported is over 1000 times greater than the pressure we experience at sea level (due to the weight of the overlying air in the atmosphere).
The heat is on
We hear a lot about global warming these days – increasing temperatures that result from higher concentrations of greenhouse gases in the atmosphere which trap heat emitted from the Earth’s surface. But the planet is heating up for another reason, namely that all of the energy that we use that is generated from non-renewable sources eventually ends up being dissipated as heat. The problem is neatly presented in a recent essay in New Sciensist, Issue 2702 [4 April 2009] by astrophysicist Eric Chaisson from Tufts University, Massachusetts, USA. The second law of thermodynamics tells us that energy eventually tends to dissipate into heat and so everything we do that utilises energy ends up generating heat that can nothing but warm the planet. Currently, this kind of heat input to the Earth system has only increased the temperature of the biosphere by 0.1 degrees Celsius but as energy use soars in the future a 3 degrees Celsius rise within 300 years is not unlikely – on top of “ordinary” global warming this is a significant amount. However, there is a way out of this problem, namely to generate energy from renewable sources. This works because energy from renewable sources is already accounted for in the global thermal budget, for example solar energy already warms the Earth so if we use some of it to generate electricity which then ends up dissipating as heat we’re not adding more heat to the system. This is another good argument for increasing our use of renewable energy sources (along with the fact that this would reduce greenhouse gas emissions) and it turns out that there’s is loads of power available in this way (there is ~7000 more power in the sunlight arriving on Earth as the current power consumption of all humans). It almost seems like a no-brainer to me.
The Arctic time bomb
It is becoming common knowledge that sea-ice is melting at increasing rates in the Arctic with predictions now suggesting that the region might be ice free in the summer by 2030. The question is, should we really be worried about this, and if so, just how worried should we be? Much of the media attention on the Arctic region is focused on how melting sea ice might alter ocean currents in the north Atlantic, but the real danger lies in what might happen as more and more of the permafrost (permanently frozen soil, water and rock) melts. Locked up in the permafrost are large quantities of carbon (which could be released to the atmosphere as carbon dioxide gas) and, particularly worrying, given its potency as a greenhouse gas, methane. If the permafrost all melts (which apparently could happen within the next 100 years) then the addition of so much carbon dioxide and methane to the atmosphere could lead to an additional increase in global temperatures of 10 degrees Celsius. Put bluntly, that would just about blast humans off the planet. Another key aspect of this issue is that it’s not a tap that can be turned on or off. If temperatures rise enough to melt all of the permafrost then the additional release of greenhouse gases will mean that there’s nothing that can be done to reverse the process. The only hope then is to try to limit the temperature increases that are already in the pipeline to prevent this runaway gas release from occuring. There’s a detailed article on this topic in New Scientist, Issue 2701 [28 March 2009] .
Visual Thinking – The Back of The Napkin
Last year I stumbled upon a book called “The Back of The Napkin” by Dan Roam which is all about “visual thinking” and how to use simple drawing techniques to solve problems. I was sitting in a doctor’s waiting room when I picked up a supplement of The Guardian newspaper and saw an article about the book. It looked like the kind of thing that interests me and so I rapidly followed this up by purchasing and then reading the book. I enjoyed it and dabbled with the ideas a bit but that was about it (although I did completely alter the way that I delivered my first year physics lectures as a result). Anyway, the author, Dan Roam, also has a website/blog and I always keep an eye out for interesting bits and pieces that appear on this so I was really pleased when I spotted an entry which links to a 60 minute presentation given by Dan Roam about his visual thinking techniques (here is a link that goes straight to the full presentation – to get this to work I have found that I need to click it once and wait for it to finish downloading and then click it a second time to actually watch presentation). I’ve just watched the whole presentation and it is a really nice introduction to the material covered in the book and has re-inspired me to look at these ideas some more.
In Defense of Food
I’ve just finished reading “In Defense of Food” by Michael Pollan (lent to me by an American work colleague). I have to say that this is one of the most thought-provoking books that I have ever read, making me question almost every aspect of my relationship with food. The book contains a really short and simple summary of its message which is “Eat Food. Not Too Much. Mostly Plants” – short, snappy and nice and easy to remember. There is lots of interesting material about how the growth of nutritionism (focusing on the nutrients within food rather than the food itself) and food science (which has replaced much of the food we used to eat with highly processed food substitutes). By pushing for ever highly yields we are now supplied with “food” that is high in calories but low in micro-nutrients and evidently this combination fails to suppress hunger (because the body still craves the micronutrients that it is not getting) and causes to eat more and take in more calories. There’s so many interesting insights and suggestions in the book that all I can really say is that you should get hold of a copy and read it for yourself. I think it is time well spent.
The other CO2 problem
Most people have been aware of the problem of global warming linked to increased levels of Greenhouse Gases in the atmosphere, but there is another problem created by the increased levels of carbon dioxide (CO2) which is only recently coming into the public realm. This is the problem of ocean acidification. The problem is nicely set out in a short film produced by children at a local secondary school (Ridgeway) in conjunction with scientists from the Plymouth Marine Laboratory. There is a piece about the film in the local newspaper from where it is also possible to view the film (or view it directly with this link).
Well done to everyone concerned.
Sea level rising faster – or is it?
New Scientist, Issue 2699 (14 March 2009) carries a rather confusing news story that reports that recent measurements show that sea level has been rising by 3 millimetres per year since 1993 which is higher than the 2007 forecast of the Intergovernmental Panel on Climate Change (IPCC). It seems that the differences comes from melting from the Greenland and Antarctic ice sheets which was not included in the IPCC forecast because of uncertainty over the models used to predict this. The IPCC forecast was for a sea level rise of 18-59 centimetres by 2100 but apparently if the current trend continues a rise of 1 metre or more by 2100 is likely. However, if you take the 3mm per year figure from the current measurements and extrapolate this out to 2100 you get a rise of about 27 cm (that’s 3 mm/year x 90 years = 270 mm = 27 cm) which is slap-bang in the lower-middle part of the 2007 IPCC forecast range. So, where’s the story gone…?
Power from seawater
A few weeks ago I wrote an entry about generation of electricity from the temperature differences that exist between seawater at the surface and at depth (OTEC) and it is common knowledge that it is feasible to generate power from waves, tidal currents or tidal water level changes. However, it is less well known – by which I mean that I had never ever heard of the idea – that it is possible to generate power from the difference in salt content between freshwater and typical seawater. An article in New Scientist, Issue 2697 (28 February 2009) introduces this idea, the basis of which is some kind of cell in which freshwater and seawater are separated by a special membrane. There are two ways that this arrangement could then lead to the generation of electricity depending on the set-up and the membrane used. First, the process of osmosis (in which water moves from a weak solution to a strong one across a semi-permeable membrane) can lead to water molecules from the freshwater side crossing the membrane into the seawater and thereby causing an increase in its pressure that can drive the water through a turbine. Alternatively, a more complex arrangements of membranes can be created that allows the salt ions to move in different directions (e.g. positively-charged sodium ions one way, negatively-charged chloride ions another way) so that the positive and negatively charged ions move towards a cathode and an anode respectively producing a voltage across the cell (basically a big battery). There are plans for a prototype power plant to be up and running soon but it does seem that this technology would only ever be a minor/local player in global power generation (despite figures that suggest it could provide 40% of the world’s electricity demands), especially as any such power plants could only ever be cited in regions where this is ample supply of both seawater and freshwater – namely large estuarine systems that are almost always both environmentally sensitive and quite highly developed already.
A Piano in the Pyrenees
Last night I finished reading “A Piano in the Pyrenees” by comedian and writer Tony Hawks (publishers mini-website here). This is the fourth book by Tony Hawks that I have read, beginning some years ago with “Around Ireland with a Fridge” and followed by “Playing the Moldovans at Tennis” and “One Hit Wonderland”. I’ve enjoyed all four books and I did enjoy reading the latest one, which is an auto-biographical account of how Hawks, on something of a whim, bought a house in the Pyrenees with the intention of using it as a place to practice the piano. The reader follows Hawks as he gets to know his new neighbours, tries to build a swimming pool and muses on love. The writing is witty but not hilarious and at times I was left feeling that it was a bit embarrassing for a nearly middle-aged single bloke to write so openly about his failures, his friends and his missing love-life etc. (his earlier books have all been based on a deliberately silly venture rather than a relatively normal chunk of his life). Still, it was an easy and fun read, and although he comes across as being someone with a certain amount of inner sadness, he does “bloke banter” very well.
Tim O'Hare 