Behind the looming shortage in Australia is a deterioration in the quality
of science education, due to a shortage of qualified science teachers and
a general undervaluing of education. The key issues, as so often stated
in the current debate, are career structure, communication and cash. Addressing
any one of these factors in isolation is an exercise in futility. But tackling
all three simultaneously could produce results.

Many top scientists chose a career in scientific research primarily
because they were inspired by an enthusiastic science teacher. Good science
teachers certainly inspire, but poor science teaching destroys the curiosity
and thirst for inquiry that children show from an early age. The consequences
are a lack of interest in scientific careers and a dwindling of the numbers
entering science teaching courses.

This trend is confirmed by the entry requirements for science courses
at Australian universities, where admission is based on a points system.
This year, the University of Queensland is asking a score of 820 in the
final year of school, 60 lower than in 1989, while the entry score for science
at the University of Sydney has dropped to the level of the lowest admissable
score for entry to the university. Corresponding falls in demand for science
education courses suggest that fewer top-quality teachers are entering the
profession, at a time when many are leaving, disillusioned and attracted
by the salaries in industry.

Throwing money at teachers to encourage them to stay in the profession
is seen by some as the best way out of the crisis. Australia’s Minister
for Education, John Dawkins, said recently that scientists, engineers and
teachers should get better pay, with significant increases going to retain
maths and science teachers. But what government could afford the enormous
costs associated with granting a significant salary increase to such a massive
number of teachers? Pay rises linked to career restructuring have been proposed,
but the proposals do not go far enough to attract the numbers required.

Consider what could evolve, however, from a constructive liaison between
science and education. The research community and teachers must surely be
able to agree on some common goals and work together to their mutual benefit.
Of utmost importance in any such collaboration would be recognition of the
damaging schism between the worlds of science and education, a divide which
must be bridged. It is enormously difficult to cross from pure science into
education or vice versa, not least because of the qualifications hurdles
each side has erected. But if teachers could also work as researchers, and
researchers as teachers, a whole range of benefits would follow.

A teacher who worked for, say, three days each week in a school and
two days in a research environment would experience science at first hand,
possibly for the first time. The diversity of the work, regular contact
with the scientific community and a wealth of resources to take back to
the classroom could serve only to increase self-esteem and a feeling of
professional worth. Renewed enthusiasm among science teachers could fire
up the next generation of potential scientists and help to stop the rot.

What would the science community gain from such an arrangement? First,
there would be a greater supply of scientific talent, after the necessary
period of in-service training. Next, the teacher-as-researcher would bring
a broader perspective to the research environment than currently tends to
be the case. And perhaps most importantly, the scientist who chose to work
as a teacher for part of the time would be better equipped to address effectively
the issue of communication of science to the world beyond the laboratory.
The image of science has taken a battering in recent years, not least because
of poor communication between scientists and the general public. Enhanced
communication through a researcher-as-teacher programme could improve this
situation, by bringing scientists out into the community to inform the public
and present a balanced scientific view on major issues.

The concepts of teacher-as-researcher, researcher-as-teacher will not
catch on overnight, given the traditional conservatism of teachers and schools,
scientists and research organisations. The cost of such an exercise would
not be insignificant, either. But even modest funding, made available as
the shortage of scientists starts to be felt, could get a programme running.
Even Australian industry might be persuaded to contribute, given its vested
interest in the country’s scientific and technological future.

Paul Butler is a teacher and science writer living in Melbourne.

SEVERAL years ago, nuclear winter the cold, dark aftermath of a nuclear war – was making the headlines. Since then, people have continued to improve their computer models of the world climate after a major exchange of nuclear weapons. The latest calculations confirm that the basic physics used in such models is correct and that the environmental impact of the war would indeed be worse than the direct effects. At the same time, it is now clear that although a nuclear ‘exchange’ might be confined to the northern hemisphere only, the south in general – and Australia in particular – would suffer devastating climatic changes and crop failures.

The theory of the nuclear winter was first aired by Paul Crutzen and John Birks in the environmental journal Ambio in 1982 (vol 11, p 114). More detailed calculations were carried out by a team that became known as TTAPS (from their surnames, Turco, Toon, Ackerman, Pollack and Sagan). The calculations suggested that soot, injected into the atmosphere from the fires started by a major nuclear exchange, would block out the heat of the Sun and change rainfall patterns, freezing the northern hemisphere – the nuclear winter effect (Eos, vol 63, p 1018; Science, vol 222, p 1283).

These claims led to a flurry of further research into the properties of the kind of soot particles that would be produced by forest fires and by burning cities and oil depots. Researchers wanted to know what changes such particles would bring about in the climate. At the same time, computer models of the workings of the atmosphere were improved.

Some of these later calculations modified the scenario of the nuclear winter, suggesting that the cooling might not be as severe as suggested in the TTAPS papers. On the other hand, studies of different aspects of the problem suggested that things could be worse than the TTAPS model.

Now, the TTAPS team has reviewed all the evidence gathered by these studies during the 1980s. The team concludes that the various adjustments that have been made to the nuclear winter model in the light of recent work more or less cancel each other out. The physics has been reaffirmed, and the picture is still one in which land temperatures in midsummer decrease by between 10 and 20 Degree C in northern mid-latitudes, while some continental regions cool by as much as 35 Degree C (Science, vol 247, p 166).

The general picture of nuclear winter now suggests that the smoke generated during nuclear war would decrease the intensity of sunlight at the ground by at least 50 per cent over the whole northern hemisphere. Sooty smoke from urban fires is the main contributor to this effect. It stays in the air for a long time because upper layers of the atmosphere, or stratosphere, may be heated by as much as 100 Degree C. Such heating evens out the temperature difference between the upper atmosphere and the ground, and so slows down convection.

This stabilising and heating of the stratosphere will help the soot to spread into the southern hemisphere. At the same time, in a new twist to the scenario, it now seems that the material injected into the stratosphere by the nuclear explosions will cause ‘severe ozone depletion’ in the north.

The estimated changes in rainfall are dramatic. According to TTAPS, the average decrease over land in July at latitudes between 30 Degree and 70 Degree North would be about 75 per cent. The summer monsoon in Asia fails in all of the forecasts. These changes, the researchers say, would be ‘unprecedented in human history’, and this ‘chronic phase’ would last for up to three years.

Over the same timescale, the smoke and oxides of nitrogen that would be injected into the stratosphere would remove at least half of the ozone there. Half of this depletion would be because the ozone is destroyed and the rest because the pall of ‘nuclear smoke’ physically pushes the ozone into the southern hemisphere. This would be a major problem once the smoke began to clear and sunlight penetrated to the ground once more. The amount of biologically damaging UV-B radiation reaching the ground at middle latitudes would be between two and three times the present dose for a year or more after the smoke had cleared.

The southern hemisphere would suffer less, but would not entirely escape the consequences of nuclear war in the north. Barrie Pittock, who heads the Climate Impacts Group in the Division of Atmospheric Research of Australia’s national research organisation, CSIRO, recently reported a study of the likely effects on Australia in a report in Ambio (vol 18). He concludes that although most of the population of Australia could survive the effects of a major conflagration in the northern hemisphere, climatic and other stresses, combined with a possible large influx of refugees, would threaten the ability of Australia to feed its own population.

The layer of smoke high in the atmosphere, spreading south from the northern hemisphere, would absorb significant amounts of sunlight for more than a year. An overall cooling of about 5 Degree C would be accompanied by a halving in rainfall, cutting farming yields by 30 per cent.

Rainfall is the limiting factor on productivity under Australian conditions, but other stresses would also be at work. The climatic changes would probably be accompanied by a reduction in the number of daylight hours from 8.5 to 6 at 30 Degree South, the latitude of Sydney and Perth, reducing sunlight for photosynthesis. And it is possible that depletion of ozone by smoke and other contaminants in the stratosphere might lead to an increase in UV-B radiation at the ground, in spite of the extra ozone being pushed south.

The good news, such as it is, in Pittock’s analysis is that the increase in the background gamma radiation produced by the spread of radioactive dust would amount to no more than one-third of the natural background dose, if there were no nuclear detonations in Australia.

And in itself, a reduction of 30 per cent in major crops such as wheat would not be disastrous, because at present Australia has a surplus. But Pittock concludes that the influx of refugees from countries more badly affected by war than Australia could tip the balance towards starvation.

A VISIT by two senior Australian scientists to Japan last month has
led to an agreement in principle on collaboration between the two countries
on research into gravity waves. The Japanese scientists expect soon to apply
to their Ministry of Education for funding next year to participate in the
construction of a gravity-wave telescope in Australia.

John Sandeman, from the Australian National University (ANU), and David
Blair, from the University of Western Australia (UWA), met Satio Hayakawa,
president of Nagoya University, and representatives from the University
of Tokyo, the Institute of Space and Astronomical Science, the National
Laboratory for High Energy Physics and the National Astronomical Laboratory.

The Japanese scientists want to collaborate with Australia on the building
of a gravity-wave telescope because Japan suffers from a high level of seismic
activity.

The Australian scientists are still waiting for a decision from the
Australian Research Council on its request for more than A$30 million (around
Pounds sterling 15 million) for the project, which would take five to six
years to complete. Meanwhile, a site has beenselected for the telescope:
a sandy areaon Wallingup Plain, near GinGin, 60 kilometres north of Perth.
The government of Western Australia has been working closely with the project
group and has already given approval for the site to be used for the installation.

An Australian gravity telescope would be unique in the southern hemisphere
and provide a link in a planned network of telescopes across the world.
The effectiveness of the network would be limited in its directional capability
without Australia’s participation. It is also the best position from which
to locate optically certain astronomical events.

The next generation of gravity-wave detectors will be based on advanced
laser technology and will have a sensitivity of more than one thousand times
as great as existing ones.

The Australians plan to work closely with Jim Hough and his team at
the University of Glasgow, who are collaborating with a group at the Max
Planck Institute for Quantum Optics in Munich to build prototype laser interferometers
(This Week, 21 January). These groups are now working together towards a
larger detector. A team at the Rutherford Appleton Laboratory, led by Ian
Corbett, is also contributing to the mechanical design, including developing
the vacuum systems.

An agreement between the British, German and Australian groups will
give Australia access to engineering design and prototype instruments in
Germany and Britain, keeping the overall cost to Australia down. Another
collaboration agreement has just been signed with French and Italian groups,
led by Alain Brillet at the University of Paris South and Adalberto Giazotto
from Pisa, who are building the VIRGO interferometer in Italy.

In the US, the Massachusetts Institute of Technology and the California
Institute of Technology are jointly proposing to build and operate two gravity-wave
telescopes on the east and west coasts. These groups are working closely
with Bob Byer, fromStanford University, who is developingthe laser technology
that will be vital to theproposed designs.

The basic design of the next generationof gravity telescopes consists
of twostainless-steel vacuum tubes, typically 3kilometres long and 1.2 metres
in diameter,arranged at right angles to one another(see Diagram). Laser
light directed alongeach pipe reflects from pendulum-suspended mirrors at
the ends, which form part of a large optical interferometer.

This interferometer will be designed to detect movements of the mirrors
of the order of 10–**18 to 10–**19 metres resulting from the passage of
a gravity wave through the device. The diameter of the tubes has been chosen
to accommodate up to three laser beams at a time, although initial designs
will be limited to single beams.

The UWA team has been working with cryogenic resonant bar gravity-wave
detectors since 1976. In building the Australian gravity telescope, the
project team will draw on the expertise at UWA in suspension and vacuum
systems for seismic isolation. The ANU group will concentrate on the lasers
and optics.

The laser light must be particularly ‘quiet’, that is, the process of
generating the laser light should not contribute to the background noise
which could mask the activity of gravity waves. Gas lasers are intrinsically
too noisy, so the ANU group are looking closely at neodymium yttrium garnet
lasers pumped by diode lasers similar to those used in compact disc players,
but much more powerful.

There are clear future applications of these lasers in medicine, for
example in laser surgery, and in industry in cutting and shaping hard materials.
The ANU team hopes to find a company willing to develop the technology commercially.

The Australian groups from ANU and UWA have recently been granted A$100
000 for research into quantum-limited noise measurements, an area whichwill
contribute to the proposed gravity telescope.

The fabrication of a lightweight high-vacuum pipeline will be needed
to build the two 3-kilometre arms of the gravity telescope; these will also
require large ultra-high-vacuum valves. The Australian companies BHP Engineering
and Dynavac plan to take part in the development of these components, which
will have applications beyond the gravity telescope.

Very flat mirrors must be built for the end of each arm of the telescope,
to an accuracy of two-hundredths of the wavelength of the laser light. Australia’s
national research organisation, CSIRO, can already construct small mirrors
to this accuracy and are ready to develop the 30-centimetre mirrors needed
for the project. The mirror coatings themselves must approach perfection.
In particular, as much of the incident light as possible should be reflected.
British Aerospace Australia is interested in developing the coatings with
an eye to developing navigational instruments such as the lasergyroscope.

* * *

The search for gravity waves

THE EXISTENCE of gravity waves was predicted by Albert Einstein as a
consequence of the general theory of relativity. Only when massive bodies
like stars interact or explode can gravity waves become energetic enough
to be detected. Their detection is a vital step in understanding relativity
and astronomy.

Our Galaxy is known to contain a large population of neutron stars and
an unknown number of black holes, each the result of the dramatic stellar
collapse which would have generated a powerful burst of gravity waves. Another
example is when two neutron stars orbit around one another, as in the well-known
binary pulsar system. These lose energy at a rate consistent with that predicted
by relativity. The final coalescence of a binary pulsar should also generate
a tremendous pulse of gravity waves. The proposed worldwide system of gravity
telescopes will monitor more than a million galaxies and provide valuable
data about such cataclysmic astronomical events.

Collaboration will be the key to making the system work. The aim is
to build a group of telescopes which would operate in conjunction with one
another, since only this configuration will allow the accurate location
of sources of gravity waves. The best configuration would be four gravity-wave
antennas, one at each of the corners of a tetrahedron. The Australian instrument
will be the only one inthe southern hemisphere, and will helpto form a very
long baseline for thenetwork.