Fit the cosmic facts
I was delighted with Roger Penrose’s article on the merits of string and twistor theory related to space and time (31 July, p 26).
Recent attempted descriptions of the universe have meant invoking multidimensional, and even multi-universe views, and exotic substances like dark matter and dark energy. These concepts sometimes appear to resemble older distractions, such as phlogiston 鈥� that strange substance chemists invented to explain weight loss during combustion processes 鈥� or the need for complex spiral planetary orbits to satisfy the religious authorities when a simple Copernican heliocentric model would suffice.
It is refreshing to see an attempt to make the theories fit our observations, rather than the observations fit flights of scientific fancy.
Letter
I may never be as fine a mathematician as the illustrious Penrose, but luckily my garden hose has three dimensions when examined closely, not just two. That comes in handy when I force a volume of water through it.
Faster future
Your article predicted that SETI, the search for extraterrestrial intelligence, should detect an alien radio signal within 20 years, based on the assumption that the growth in computing power will slow after 2015 (24 July, p 24).
Given the way quantum computing is progressing, with the first successful large-scale commercial implementation estimated to be only 10 years away, the calculations should account for an accelerating rate of growth in computing power instead of the opposite, don’t you think?
Flipping patients
Lucy Porter has designed a plastic virtual reality headset to work in an MRI scanner to reduce the claustrophobic experience (10 July, p 20). It is a clever high-tech solution to a high-tech problem. May I suggest a possible low-tech one?
Back in the good old days when I was thinner, much thinner, I used to go caving. It was quite noticeable that struggling to get through a nice tight passage with rock above and below you was much more fun on your stomach than on your back. In fact, there seems to be something profoundly unnatural about lying on your back with a hard surface just above your nose.
Most MRI scans are done with the patient in just this position: perhaps the low-tech solution is just to turn them over.
For the record
鈥� In the article on the plan to elevate Venice (24 July, p 36) we refer to team leader Giuseppe Gambolati as an applied mathematician. He is in fact a geomechanical engineer.
鈥� Marion Hoar of Haydensville, Massachusetts, US, points out that if Napoleon was given 600 milligrams of mercuric chloride, he certainly was murdered (24 July, p 16). Mercuric chloride is an abandoned, very toxic disinfectant. Mercurous chloride, or calomel, is an abandoned but much less toxic laxative and purgative.
Bali bomb response
I am head of the emergency response team here in Bali, where I live and work. I was invited to take on this role as a result of my actions in the Bali bombing of 2002. Frank Furedi’s comments about how communities respond to disasters appear to be confirmed by our experiences here (8 May, p 19).
The situation during the first, crucial 24 to 36 hours after the bomb, which I coordinated, was handled by a massive group of more than 400 volunteers who came together and efficiently functioned as a single unit. We brought order to chaos and resolved hundreds of complex situations that the authorities were not able to deal with.
Even after this initial period, the volunteers were the backbone of the entire effort. Government agencies unfortunately proved to be incapable of relevant responses, having nothing to guide them.
For example, we contacted the US consulate in Surabaya, a city on the neighbouring island of Java, and advised them we had one of their nationals in a terrible state with 60 per cent burns. They responded by asking if he had a credit card to pay for his own evacuation. Incredulous at this reply, we pointed out he had almost no skin, let alone a credit card 鈥� but the official could not offer or suggest any constructive course of action. We subsequently arranged to have him flown to Australia.
This lack of relevant response was mirrored by many of the government representatives we contacted throughout the crisis. They were for the most part at a loss and unable to improvise. It is to the credit of the Indonesian authorities that they reacted and embraced this spontaneous assistance from the community in this time of desperate need.
This would appear to reinforce Furedi and the Disaster Research Center’s findings that a group of people with a single intention and clear goal and, most importantly, local knowledge, can be more effective than anyone could ever imagine in a disaster situation. Governments seem to have a problem acknowledging this.
Our nuclear future
The letter on the cost of nuclear power from Peter Jennings deserves an answer (31 July, p 24).
For 40 years, he has been waiting to hear of a permanent method of disposing of nuclear waste. He has missed the boat. It has, for many years, been perfectly possible to glassify waste and bury it thousands of feet below ground.
The only objection to this, endorsed by the UK government in its report Managing Radioactive Waste Safely, was that this would make it impossible to recover material when it became valuable 鈥� an objection that supporters of nuclear power can endorse, but which is hardly consistent with the position of objectors.
The report mentioned, but specifically did not endorse, the suggestion that relatively heavy radioactive particles would escape from state-of-the-art sealed containers and make their way back, via groundwater, in sufficient quantities to increase the background radiation.
It is also possible to bury the material in areas where the mantle is being subducted towards the Earth’s core. If buried in this way it is unlikely it would be recycled to the surface within the lifetime of our planet 鈥� though this seems a degree of overkill.
On cost, let me put Jennings’s mind at ease. The cost of burying a few tens of cubic metres of waste is insignificant compared with the cost of dismantling the tens, perhaps hundreds, of thousands of windmills we would need to replace nuclear power.
The major cost of removing windmills is not, as he imagines, dismantling the tower, but removing up to 1000 tonnes of poured concrete making up the foundation. The wind industry has guaranteed to remove this but, unlike the nuclear industry, is not required to lay aside money for it.
Let me set his mind further at ease. He refers to the problems of storing high-level waste for 100,000 years. Since high-level waste has, almost by definition, a short half-life, almost all such waste including retired reactors themselves will be down to safe levels within 50 years and indistinguishable from background levels within a few hundred.
Nuclear power is not only cheaper, more reliable and less polluting than the alternatives, but the only arguments against it turn out to owe more to hysteria and Luddism than good science.
Towering oversight
I read with interest your article “Power Tower” (31 July, p 42).
As a rather simple back-of-the-envelope calculation will establish, the amount of energy necessary to obtain the raw materials and erect such a gigantic solar tower would be considerably more than the estimated energy extracted. Therefore it is not a truly renewable resource and can be erected only if there is sufficient fossil energy left on Earth.
However, there might be a value if the generated power could be used to create an oasis of vegetation with its own ecosystem in the Australian desert. This may be sustainable. Colonel Gaddafi is attempting to do something similar in the Libyan desert.
A decent carbon burial
Whilst I agree with Frederic Hauge and Marius Holm about the potential value of carbon storage in mitigating climate change, I think that they understate the possible risks arising from leakage (17 July, p 16).
Using a high-emissions scenario, the atmospheric concentration of carbon dioxide might not peak for 250 years. Hence, if large amounts of stored CO2 did leak out of reservoirs in just 100 years, it could seriously exacerbate the problem of climate change in the next few centuries. Storage for thousands of years is more prudent.
There may also be absolute thresholds in the ability of ecosystems to cope with ever higher concentrations of CO2. These would require that some of our fossil fuel reserves remain unutilised.
Bohr is still wrong
A number of your readers have pointed out that Shahriar Afshar’s grid wires are placed in just the positions that would form a diffraction grating creating an image of pinhole one at the position of the pinhole-two image (7 August, p 24). Does this destroy the purity of Afshar’s “which-way” measurement (24 July, p 30)?
I raised the same question with Afshar earlier this year, and the answer is no. The reason is that the wires intercept no light and so cannot diffract. He has done a variation of his experiment using only a single wire and recorded all the light in the focal plane of the pinholes under three conditions: wire in, one pinhole; wire in, two pinholes; and wire out, two pinholes.
The first shows lots of scattering from the wire away from the image points, indicating that with only one pinhole open the wire is intercepting and scattering light. The second and third set-ups show clear images of the pinholes with nothing in between and are indistinguishable.
The conclusion is that no light is scattered or intercepted by the wire in the second case, because the interference pattern is present and the wire is at a zero intensity position in the pattern. A single wire cannot function as a diffraction grating. Bohr is still wrong.
Yawning warning
Your article reports that contagious yawning in chimps suggests an ability to understand others’ state of mind (31 July, p 15). This study errs by trying to answer the question “do chimpanzees empathise?” without having answered the question “why are yawns contagious?”
Though it is commonly believed that yawning is a self-arousal technique or, as suggested in the article, a signal for bedtime, neither theory explains why carnivores yawn and herbivores don’t.
I propose that yawning is merely a display of teeth, intended to give enemies second thoughts about ambushing a drowsy foe. This would explain why more docile mammals, with no fierce teeth of their own, don’t yawn. With our less than intimidating jaws, we primates may have adapted communal yawning as a means of showing our strength in numbers.
From this perspective, contagious yawning does not indicate empathy at all. Instead, it’s a purely autonomic means of warding off unseen predators, courtesy of mother nature.
Letter
Please reassure me that I was not the only reader to find myself trying, unsuccessfully, to stifle a yawn while reading the article under the photograph of a yawning chimp. The article’s subject? Contagious yawning.