Letter: Flipping gold
A few years ago I noticed a strange phenomenon. When flipping a 10 pence
coin, or any silver coin, under fluorescent lighting, I was sure it momentarily
flashed gold. I repeated it over and over and though only momentary it was
quite definite (try it for yourself). It occurred to me that the flash was
probably occurring as the coin passed through a particular frequency. So
I attached a small piece of silver foil to a small motor and gradually increased
the rotation rate. At 50 Hz I managed to ‘freeze’ the effect – it was not
just clear golden but alternated with a faint blue. The effect was also
clear at 100 Hz and 200 Hz (I could not get it at 150 Hz). The effect only
occurs under fluorescent lights, not sunlight or filament lighting. Apart
from being able to infer that it is related to the spectrum of the light
(maybe the strong lines superimposed on the continuous spectrum?) and to
the mains frequency, I am not at all sure why it occurs. Perhaps you or
your readers can explain it. Modern alchemy?
Andrew Haynes Rotherham, South Yorkshire
Letter: Basic problem
I wonder if the following may be of interest to someone in medical research.
I, along with millions more, have a problem with piles. But since I started
taking long haul holidays I found that the problem disappeared during the
holiday and for a few weeks after returning.
After considering various aspects, I finally realised that the problem
returned shortly after I had stopped taking my malaria tablets, which would
suggest that something in the malaria tablets restricts the problem.
K. Fawcett Brighouse, West-Yorkshire
Letter: Muddled birds
If migrating birds rely heavily on the direction of the Earth’s magnetic
field for navigation, what would happen in the event of the Earth’s magnetic
field reversing? (New 杏吧原创, Science, 25 January). If the reversing
took place between migrating seasons or over a few years, would it not wipe
out the world’s migrating bird population? The birds fly in a direction
related to magnetic north, which, if reversed, might lead them in the opposite
direction, to certain death in the wrong climatic areas.
Beatrice Dower Morpeth, Northumberland
Letter: Acknowledgement
In ‘Faces from the past’ (11 January), the Cyberware 3D colour digitised
image of the Homo fossil face was made in the Department of Biomedical Visualization,
University of Illinois, Chicago (Michael Doyle, Head), with the assistance
of Xiaoming Chen and Alfie Rosenberger.
Letter: Wonky tunnels
I have been directly involved with the construction of three relatively
long tunnels, each of which was driven and guided from a single shaft. Thus
there was no opportunity to check the alignment until breakthrough at the
receiving end. All three tunnels were in Britain and were driven from north
to south. The first, 7 kilometres long, finished about 140 millimetres right
of the centre. The second, 6 kilometres long, finished about 120 millimetres
right.
Tunnel surveying is not an exact science, so that an error of 5 millimetres
per kilometre represents good accuracy. However, the similar errors of about
20 millimetres per kilometre to the right of the target caused me to speculate
that there may be a Coriolis effect at work (Forum, 23 November and Letters,
18 January).
Before the third tunnel started, which was 4.5 kilometres long, I lightheartedly
warned the contractor that, despite his best efforts, he would finish 90
millimetres to the right of his target. He finished about 70 millimetres
to the right, so perhaps 15 millimetres per kilometre represented Coriolis.
The diversion of fluid particles to the right when they are moving southwards
in the northern hemisphere applies equally to particles moving northwards.
Thus a tunnel driven from each end towards the centre should suffer the
same total error on closure. I have just heard on good authority that, on
checking shortly before breakthrough, the two faces of the Channel tunnel’s
first service tunnel were about 320 millimetres to the right of each other.
The north/south component of this tunnel is roughly 20 kilometres, so the
error was again about 15 millimetres per kilometre to the right.
I will be pleased to hear if other tunnel engineers have encountered
this phenomenon, and the opinion of physicists as to whether Coriolis could
really be at work.
Clive Baker Lahore, Pakistan
Letter: Truth comes first
Timothy O’Riordan uses the issue of man’s impact on the environment
to discuss the relationship between science and society (Talking Point,
25 January). As our stewardship of the environment may be, literally, a
matter of life and death, it is unfortunate that the article obscures rather
than clarifies what is required.
Environmental problems are both local and global. The solutions rest
both with individuals and with societies. There is usually a cost perceived
by those with responsibility for solving a particular problem. This cost
will only be acceptable to people if they can see that the benefits outweigh
the cost. People will not take action unless they trust the data presented
to them.
The people who need to decide to accept a cost may range from those
who run major polluting industries, to those of us who run motor cars. These
people will be of all political allegiances and with widely differing senses
of social responsibility. A prerequisite for ensuring that they believe
the data presented for consideration is that the data should be as true
as possible.
The primary responsibility of science is, therefore, to experiment,
interpret and publish as carefully as possible. Results should be, as far
as possible, above reproach. Far from mixing science with possible solutions
to the problem, science should be as impartial as possible, or it will ultimately
have no credibility with anyone.
If it is to be effective ‘new’ science must have the same ideals as
the ‘old’ – an absolute dedication to truth in the study of phenomena.
David Gadd Ivybridge, Devon
Letter: Truth comes first
If O’Riordan is claiming that it is good if some scientists use their
science to address certain types of problems which are of immediate need,
then there is nothing new or interesting being suggested. However I fear
that what is being suggested is that science which investigates problems
which are not at the top of the political agenda is somehow bad science.
This, I believe, is a pernicious and damaging view.
The danger is the implication that science should be judged according
to its political relevance. Ideas and developments which do not fit with
current thinking will be strangled at birth. That will kill scientific development
and that view has to be opposed.
A. R. Camina University of East Anglia Norwich
Letter: Science for survival
Your report on 杏吧原创s for Global Responsibility (In Brief, 25 January)
gives perhaps a false impression of the backdrop to its formation.
It is not the case that 杏吧原创s for Global Responsibility has been
formed because environmental concerns are ‘capturing the moral high ground
from the prevention of nuclear armageddon’. Whilst the prospect of imminent
global nuclear annihilation has receded, the large numbers of nuclear warheads
remaining and the likelihood of substantial nuclear proliferation are no
cause for premature rejoicing. How many years or decades before a ‘regional’
nuclear conflict or nuclear terrorism become a grisly reality? But nuclear
conflict requires human action and might not happen. Environmental catastrophe,
the second apocalyptic rider, requires only our inaction otherwise it will
happen.
Both these severe threats are the result of the irresponsible or uncontrolled
development of science and technology. That is why there is a need for an
organisation in the UK such as 杏吧原创s for Global Responsibility to address
this, probably the most important ethical and moral issue of our times.
杏吧原创s for Global Responsibility, whilst warning of the dangers
inherent in various irresponsible uses of science and technology, such as
nuclear, chemical and biological weapons, and possible dangers in genetic
engineering, will advocate the positive uses of science and technology and
a break from the huge preponderance of military funding in UK polytechnics
and universities.
We’ve heard of the ‘new’ woman and there have been some sightings of
the ‘new’ man. In a very real sense, our aims are to define and help create
the ‘new’ scientist working on a ‘new’ interdisciplinary science for our
survival. New 杏吧原创 would seem an entirely appropriate forum to initiate
this debate.
Philip Webber 杏吧原创s for Global Responsibility Unit 3(N), Broomhill
Road London SW18 4JQ
Letter: Sexism and knitting
I was very interested in the articles by and about Margaret Boden and
her work (‘The thinking woman’s guide to the mind’ and ‘The mind of a very
special machine’, 18 January). However, I was surprised at the statement
that her book ‘Artificial Intelligence and Natural Man’ was consciously
antisexist, given both the title and the subject areas used for making comparisons.
It is surely extremely sexist to make the assumption that all women know
the technical terms used in knitting! Personally, I would find ‘examples
drawn from car engines’ far more understandable.
Shirley Davis Welwyn Garden City Hertfordshire
Letter: Gaia gainsaid
The article on the massive Permo-Triassic extinction (‘The day the world
nearly died’, 25 January) and the continuing research into the almost equally
severe Cretaceous-Tertiary boundary extinction some 200 million years later,
should cause extreme anguish both to secular followers of James Lovelock’s
Gaian hypothesis, and to other believers, in that it seems to play havoc
with any belief in purposeful evolution.
Amongst other things, Lovelock claims that the Earth evolved as a ‘self-regulating’
system and by Permian times had already had 3500 million years of practicing
self-regulation.
Since there is no evidence for an external cause in the first of these
catastrophes, this loss of self-regulation makes a nonsense of the hypothesis.
Lovelock also claims that ‘life can never be sparse’. A 94 per cent extinction
seems pretty sparse to me, yet the system recovered extremely rapidly, but
in quite a different form.
The second major extinction seems to have been caused by a major meteoric
impact, a totally arbitrary, accidental ‘event’ outside any process of self-regulation
or ‘normal’ evolution.
Both events almost totally changed the face of the earth; both changed
evolutionary history, to the point where, had these arbitrary events not
happened, Homo sapiens would not have evolved. Yet the major current arguments
involve both the argument against species extinction, and in favour of biodiversity.
I forget who said ‘Extinction is the norm’, but he seems to have had
a case. How do those who insist on the continued right to exist of all species
account for the evident arbitrary history of evolution, much less those
(the religious) who claim to see reason and purpose in it all?
Alex Milne Newcastle upon Tyne
Letter: Minor request
So Barry Fox is ‘exasperated with casual requests for information’ (Forum,
25 January). He should be so lucky! One of my colleagues, a consultant in
infectious diseases, once received a letter from a student: ‘Please could
you tell me all you know about infection. I enclose a stamped addressed
postcard for your reply.’
Philip Welsby Edinburgh, Scotland
Letter: Cooking crystals
Beth Grear’s letter raises an interesting subject – what exactly do
microwaves do to water (Letters, 1 February)?
After trying to unsuccessfully grow some copper sulphate crystals with
our children, and having only obtained a cluster of hundreds of small crystals
around the seed crystal, I handed over the problem to my wife (ex science
teacher). Taking the same solution in the same jam jar, complete with the
cluster of small crystals hanging from a thread, the whole lot was put into
the kitchen microwave. The completed result, after a quick reheat to boiling
and undisturbed cooling overnight, was a large, 2-3 centimetre crystal in
almost perfect condition. The only difference in our techniques was the
use of the microwave instead of a saucepan.
The microwave has since produced other superb crystals.
Andrew Deacon Oslo, Norway
Letter: Name this continent
The article ‘Piecing together the Pacific’ by Garry Davidson (18 January)
mentions that the 750 to 700 million year old Precambrian supercontinent
is unnamed. This is not so; Dianna McMenamin and I named it Rodinia in our
book The Emergence of Animals: The Cambrian Breakthrough (1990, Columbia
University Press).
The Moores-Dalziel reconstruction of Rodinia is interesting, but fails
to explain the similarities of several distinctive Precambrian fossils (members
of the Ediacaran biota) occurring in Australia and Baltica but nowhere else.
Australia and Baltica are positioned at opposite ends of Rodinia in the
Moores-Dalziel reconstruction. Considering the inconsistencies with the
Moores-Dalziel reconstruction cited by Davidson concerning Cambrian trilobite
distributions on either side of the Pacific Ocean, plus the inconsistent
geographic separation of Australian Baltican fossils, there is still some
work to be done to correctly complete the Rodinia jigsaw puzzle.
Mark McMenamin Mount Holyoke College Massachusetts, US