Roughly sunrise
Stewart says: “Quantum stuff apart, we can state with assurance that there really is no such thing as randomness.”
What we call the randomness of an event may be relative to a particular level of description of that event, but this isn’t to say such randomness doesn’t exist. What we generally mean by randomness is unpredictability from a typical or relevant standpoint. This standpoint is rarely that of an omniscient being, so whatever discoveries are made at a micro level, people will continue quite justifiably to describe some things as random and others as not.
Clear about Coriolis
Feedback is too harsh on the West Australian’s reply to the question of why whirlpools rotate in different directions in the northern and southern hemispheres (25 September). The explanation given is both crystal-clear and correct.
It is substantially easier to remember than the usual “deflection is to the right in the northern hemisphere and to the left in the south” rule that is normally applied to rote learning of the effects of Coriolis force. With a little thought, it also shows why hurricanes remain confined to their own half of the globe, and disposes of the usual arguments about whirlpools in two adjacent bathtubs on opposite sides of the equator. Thanks to Feedback I can now add this to my armoury when teaching rotational dynamics to second-year physicists.
Harriet and Venus
Just when we astronomers have been stressing that nobody alive had seen a transit of Venus until the one on 8 June this year, since the previous one was in 1882 and the oldest person on Earth is 115 years old, along comes Harriet (11 September, p 38). Though she is a tortoise, I’m delighted to learn that 173-year-old Harriet, from her perch in the Galapagos, may well have seen the transit of Venus of 1882 and even of 1874.
Use the bag again
Did I miss the point when I read your article about plastic shopping bags, or was it the author 鈥� and possibly the Carrier Bag Consortium (11 September, p 30)? To me, the main problem is not the use of plastic bags per se, but the mentality of “use a bag once and then get rid of it”, as mentioned all too briefly in the article.
Yes, by all means use a plastic bag (if you prefer that to a string bag, or heavy-duty cotton bag, or whatever your taste may be). The important thing is to reuse it for the same purpose for which it is designed 鈥� carrying things. It is ludicrous to imply that the only alternative to single-use plastic bags is single-use paper bags or cardboard boxes.
Turn the TV off
I was appalled by the suggestion of leaving TVs in the US on standby, ready to be activated remotely in case of emergency (25 September, p 24). The article failed to pick up on the fact that this could only enhance the country’s position as the world’s biggest consumer of natural resources.
Domestic appliances such as TVs and videos still consume power while on standby, making them major wasters of electricity. The suggestion that all households should have a TV permanently on standby “just in case” seems likely to do major environmental harm.
Really hard problem
Richard Wilson tries to demystify the “hard problem” of consciousness by citing what he describes as the emergence of water from the combination of two gases, hydrogen and oxygen (2 October, p 31). This comparison of water with consciousness breaks down at critical points.
True, water has different properties from those of elemental hydrogen and oxygen. But they are still just measurable physical properties such as mass, volume, temperature and pressure, which have no application to consciousness.
Furthermore, when combined to form water, hydrogen and oxygen lose their original properties and cease to exist in their gaseous states. The neuron networks that supposedly generate consciousness undergo no such transformation. They continue to exist as the observable physical structures they are, without becoming a constituent element of the consciousness they supposedly generate.
Devotees of naive materialism routinely dismiss any doubts that neuroscience will eventually solve the “hard problem” of consciousness. It is evident to me, having followed this discussion for many years, that this confidence is based on nothing more than blind faith.
Waste of good fish
Whether or not harvesting fish for aquaculture is sustainable, it is without doubt a waste of perfectly edible fish (2 October, p 16).
Your report mentions two species: horse mackerel and blue whiting. The former turn up regularly on the south coast of England during the summer. Given the choice between a piece of farmed salmon or a horse mackerel, I would give the farmed salmon to the cat and eat the horse mackerel. They are a delicious oily fish. Whiting, too, are excellent, as an ingredient for fish cakes or fish fingers.
If we knew how to make proper use of the range of available fish species, it would cease to be economic to catch perfectly edible fish and use it as fish food. Aquaculture has its place, but the appropriate species are sedentary herbivorous fish such as carp, which have been farmed for centuries.
Shooting down missiles
I cannot say for certain whether a nuclear missile defence system is possible, or, as Theodore Postol claims, impossible. I can say that his claims are based on insufficient data to make a determination, as they rest on only two examples: the inability of the Patriot missile to intercept Scuds in 1990, and the shooting down of a friendly aircraft in the more recent Iraq war (2 October, p 23).
In the first instance, a point-defence anti-aircraft weapon that had been intentionally downgraded to prevent it from being used as a missile interceptor was asked to perform as an area-defence weapon against missiles. While few if any warheads were intercepted, the Patriots actually intercepted many of the Scud boosters. It should, incidentally, be noted that they performed magnificently in their main political role: keeping Israel out of the conflict. In the second instance, Postol has uncovered two incidents where the Patriot failed to distinguish friend from foe in the heat of battle.
One only has to look at the improvements in targeting technology between the laser-guided weapons of the first Gulf war to the GPS-guided weapons of the second to see that huge leaps in this sort of technology are not uncommon.
Hungry rescue rats
The idea of rescue rats trained to locate trapped survivors is appealing (25 September, p 21). However, I note that the design has feedback only to the pleasure area of the rats’ brains, not to the “don’t eat that, it tastes vile” area, if there is such a thing.
Which leads one to ask what the first instinct of a rat will be on finding a wounded, immobilised person?
Hungry rescue rats
As I read through the article I kept expecting to come across one piece of information which was disturbingly absent from the report. By what means are the rats’ natural appetites suppressed?
The Editor replies:
鈥� A number of readers have asked what the rescue rats will do on encountering a human body under rubble 鈥� in particular, whether they will start nibbling it? The researchers say they have found that even hungry rats will ignore buried sweetened cereal in favour of continuing to search for the target odour 鈥� a person 鈥� in anticipation of the reward of “several pulse trains” to their pleasure centre when they find it. In their tests, the team has not found it necessary to administer any aversive stimulation to prevent the rats taking a bite. They also consider that it would not be humane to do so.
Addled add-ons
Just before I received your 2 October issue, I “upgraded” my PC with XP Service Pack 2 using the “automatic update facility”. Now I discover from your article (p 26) that Microsoft knew that this might block some of my add-ons. Now my digital radio adapter and my TV tuner adapter don’t work.
I understand that Microsoft is a leading member of the Federation Against Software Theft. Is there any organisation that can protect millions of PC owners 鈥� who have paid for their PC, their Windows operating system and their applications 鈥� from action by Microsoft that deprives them of access to their television and radio?
Dream plugs
If dreams are to stop your sleep being interrupted by noise in the real world (18 September, p 9), do people who sleep with ear muffs or earplugs have fewer dreams?
Roughly sunrise
Ian Stewart should have used a different example of precise prediction than the time of sunrise, which cannot, as he claims, be predicted within fractions of a second (25 September, p 28).
While the sun’s physical direction in space with respect to any location on the Earth can be predicted precisely, albeit within limits subject to irregularities in the rotation rate of the Earth, its apparent position is affected by refraction in the Earth’s atmosphere by an amount dependent upon atmospheric pressure and temperature, and this effect is particularly pronounced near the horizon.
As Jean Meeus states on p 103 of Astronomical Algorithms: “Giving rising or setting times of a body more accurately than to the nearest minute makes no sense.”
Tackling bird flu
Your article suggested that nothing meaningful could be done to help most of the world’s population if a bird flu pandemic develops (2 October, p 10). This may be too pessimistic. If antiviral neuraminidase inhibitors taken early prove effective there is a possible approach.
Patients could be allowed private prescriptions, one per family member. That would bring the drug into the population early and many would now take out this insurance against the disease. It would help push up production targets. Even if only wealthier people responded, this strategy would create a firewall.
Any population-wide scheme has risks. But with the possibility of millions of deaths, now is the time to establish large pilot trials.