The Age from Melbourne, Victoria, Australia • Page 13

THE AGE, Monday 10 June 1985 13 EDITED BY philip Mcintosh FUTURE AGE a Giant eyes peer deep into space From San Francisco IAN ANDERSON reports on US plans for orbiting telescopes that will revolutionise astronomy. Another camera will take both sweeping views of distant galaxies and high resolution photographs of planets in our solar system. Other instruments will measure the chemical composition of faint light sources, determine distances by precisely measuring light intensity, and explore the physical characteristics of interstellar gas clouds and matter escaping from stars. The telescope is expected to be operational for 15 years. For nine of those years it will complement the world's largest ground-based telescope which will be built at a cost of $US85 million on Mauna Kea, a mountain in Hawaii.

Called the Keck telescope, it should be completed in 1992. It will see some objects better than the Hubble telescope because its reflecting mirror of 10 metres will be more than four times larger and capable of collecting 18 times more light But atmospheric conditions will still limit its maximum penetration to about four billion light years. The Hubble telescope may have to be brought back to Earth every so often for a major overhaul, but that would be a drastic step. NASA would prefer that it be serviced either from the shuttle or in a workshop planned for the manned space station which should be in orbit by 1993. The space station will play a central role in the other four orbiting telescopes, all of which should be launched by 1994 unless funding suddenly dries up.

One of the telescopes the as-trometric telescope is actually planned to be part of the space station and may be one of the early payloads. It may be tethered to the station to reduce vibrations. The telescope has a specific purpose it measures the movement of heavenly bodies relative to one another and is expected to detect planetary systems in other galaxies. The measurements, which rely on visible light, need to be made over many years. Supporters of the astrometric telescope within NASA say that it will be more effective at finding planets and planetary systems than the Hubble telescope because the glare of bright objects might obscure the weaker signals from planets.

The space station would service the other three telescopes which would fly in a higher orbit. A manned spacecraft called an orbiting manoeuvring vehicle will be sent out to do repairs, or the telescopes could be hauled back to the workshop. The gamma ray observatory, which will detect the shortest wavelengths of the electromagnetic spectrum, is due to be launched in 1988. It will monitor the most violent cosmic events such as nuclear fires in extremely hot exploding galaxies. The advanced x-ray astrophysics facility, set for a 1991 launch, will explore the radiation produced by stars as they are sucked into black holes cosmic objects so dense that light cannot escape.

The fifth telescope will need replenishment of a coolant liquid helium every two years. Operating in the infrared, the telescope is simply a highly sensitive heat detector. But to prevent measurements being contaminated by its own heat, the telescope must be cooled to within a few degrees of absolute zero (minus (273 Celsius). Regular replenishment of the cryogenic fluid is an ideal job for the space station. Called the space infrared telescope facility (SIRTF), it could push observations back to 15 billion light years.

Viewed from Earth, the objects on the outer limits of the universe are receding at almost the speed of light 299,330 kilometres a second. Radiation is emitted at the red end of the spectrum. The faster the object moves, the greater its "red shift" appears to be. SIRTF will measure this movement. Astronomers preparing SIRTF for a 1993 launch hope that it will detect and analyse so far undiscovered These are clumps of condensing molecular gas and dust that have not yet turned on their thermonuclear fires.

They could hold the key to the process of star formation. Another target will be "brown which could be giant planets or "failed SIRTF will also explore in detail some 300,000 previously unknown objects detected in 1983 by the highly successful infrared astronomical satellite (IRAS) which mapped the sky in the infrared. SIRTF will be 1000 to 4000 times more sensitive than IRAS. The telescope will cost almost 5US600 million to build and operate for one year. It is a cost that has yet to be approved by Congress, but the lure of the unknown is so great that funding should be forthcoming.

AZE at the heavens this i evening. If it is a clear night without too much atmospheric pollution and you have good eyesight, the most distant objects you see will be some 600,000 light years away. That is about the viewing limit of the unaided eye. Ground based observatories can dp better, but surprisingly not that much better. The largest telescopes can detect light emitted from objects two billion light years away from our galaxy.

Their view is restricted by the shimmering effects caused by the dust and moisture of the Earth's atmosphere. But soon the heavens will open up. We are about to enter a golden age of astronomy from space. It is being hailed as the greatest revolution in astronomy since Galileo invented the simple telescope 370 years ago. The National Aeronautics and Space Administration (NASA) in the United States is devising five entirely different telescopes to be deployed in space.

By orbiting well above the Earth's atmosphere, they will push the limits of the known universe back to at least 14 billion light years seven times the current limit. A light year is the distance light travels in one yean 9.45 trillion kilometres. Each telescope will operate at a different wavelength of the electromagnetic spectrum and "see" events that might be missed by one of the other telescopes. Some objects, for example, will be too cool to be seen by optical telescopes. But like the darkened embers of a fire they will still be emitting heat and energy that can be detected in the infrared.

The burned-out remnants of a dead 3l rSUNSHADE Mj INSULATION I CUUfc VALVE 'suPERFLUlO HELIUM TANK The space infra-red telescope facility in flight (above) and in detail (left). It will look stars" and "brown star or the slowly coalescing gases of a yet unborn star could be seen in this way. But violent events such as exploding stars or hot gases being sucked into black holes release so much high energy that they require detection at the other end of the spectrum. Also, astronomers now realise that the universe is far more diverse and volatile than was earlier imagined. Its mysteries can only be solved by a variety of instruments.

The biggest mystery of all is the creation of the universe. In a few years we will able to see back to that time. Astrophysicists believe that the universe is between 15 billion and 20 billion years old. By penetrating to 14 billion light years and beyond, the telescopes will be viewing events that occurred as stars and their systems galaxies were formed. Other instruments will look in detail at closer celestial phenomena.

Also, astronomers will benefit greatly from a network of tracking and relay satellites that is gradually being put into orbit some 34,000 kilometres above the Earth. Astronomers will have continuous and rapid communication with the telescopes. The flagship of the new telescopes will be the Edwin P. Hubble space telescope. Named after a pioneering American astronomer, the telescope will explore 350 times the volume of space that can now be seen by the best ground-based optical telescopes.

It will peer to the edge of the universe, 14 billion light years away. After eight years of delays and escalating costs, the telescope is now nearing completion at Lockheed Missiles and Space Company in California. It is due to be finished in March next year. Its size (13.1 metres long with a diameter of 4.25 metres) and weight (11,250 kilograms) will make it too big for transport by air to Cape Canaveral in Florida. Instead it will be shipped through the Panama Canal.

It is scheduled to be launched aboard the space shuttle Atlantis on 8 August 1986 and deployed at an altitude of 593 kilometres. The total cost will be SUS1.3 billion, about twice the estimated cost when first approved by Congress in 1977. Intense excitement surrounds the telescope. Astronomers can only guess at what it might find. White dwarfs, quasars and exploding stars called supernovae will be viewed as never before.

Known objects will be seen with 10 times the clarity and thousands of new discoveries will be made. The instruments will locate objects 50 times fainter than those seen by Earth-based observatories. About 4500 hours of observation will be possible each year, more than double the the observation time achieved from Earth. Also, it will be able to detect ultraviolet light which is screened out by the Earth's atmosphere before reaching ground-based observatories. Engineers are already trumpet- PRIMARY MIRROR Turtles take over island in record nesting season away.

The secondary mirror will send the light through a hole in the centre of the large mirror, back to the scientific instruments. Five instruments will be on board. The European Space Agency is building a camera to photograph objects so faint that cumulative exposures over many orbits will be required to produce an image. Among other things it will search for yet to be discovered planets. ESA is also constructing the solar arrays that will power the telescope.

In return European scientists will be allocated about 15 per cent of the telescope's observation time. ovary that has laid up to 1000 eggs in a nesting season looks very different to one that has never laid eggs at all, even if, as now seems likely, such seasons are five to 10 years apart. Such recovery as there is takes at least a year while the expansion of blood supply to the ovary and the storage of the necessary fat takes a similar period. It was with this technique that Limpus predicted the big turtle year on Raine Island. Most of his research on green turtles is done at Heron Island where, for many years, he and Phil Reed have tagged every turtle coming ashore to nest.

In 1983-4 few nested and, in their feeding grounds offshore, only a small proportion had large ovaries. Some 60 per cent however, were preparing to breed in 1984-5. The southern Barrier Reef was going to have a big year. The opportunity to study turtles nesting at Raine came unexpectedly. Turtles tagged at Raine had been found on feeding grounds as far apart as Indonesia and the Solomons and few Raine turtles were thought to spend their non-breed STEPHEN GARNETT was on the Great Barrier Reef to watch the biggest green turtle nesting ever recorded in the world.

He reports on research on the turtle's breeding habits. tant It will not need a cyclone to predict the number that will nest at Raine; that can be done much more easily at Heron. Further, should the Raine Island turtles be over-hunted at their largely unprotected feeding grounds, there will be a discrepancy between the predicted and actual number nesting there. Over-exploitation can be detected in the year it occurs, not 50 years too late. The next step is to discover the environmental trigger that simultaneously stimulates breeding by green turtles over a large part of the Pacific and Indian oceans.

That discovery should benefit not only the turtles but also many tropical marine industries. Bodies funding biological research would do well to follow the example being set by the Queensland National Parks and Wildlife Service in sustaining support for long enough to answer not only their own management questions but much else besides. Dr Stephen Garnett has been researching turtles in Torres Strait for six years. SECONDARY MIRROR ing the stability of the telescope's guidance and pointing system. The precision is such that it could focus on a dime in Los Angeles from a vantage point in San Francisco, 700 kilometres away.

The 2.4-metre mirror is the heart of the telescope. Its surface is so fine that if it were scaled up to years old. Not so. When Limpus measured the growth rate of immature turtles he found it would take at least 30 years before they reached the size of the smallest breeding female. Many would not breed until they were over 50.

One implication is that any reduction in breeding population now, say from over-hunting in the Gulf of Papua, could not be detected on the nesting beaches until well into next century. Mr Limpus has discovered, along with fellow workers Phil Reed and Jeff Miller, that temperature, not genes, determines the sex of young turtles. In a par-, ticularly hot summer most of the Dr David Kemp the parasite in some parts of the world. Dr Kemp said the ability to identify different strains of the parasite would help scientists to track their activity in the population; to see whether certain strains were eradicated and possibly replaced by others. One of the problems of vaccine development was that a vaccine might be effective against one strain of the parasite, but then another strain appears in the population.

"Now that we can follow the genetics of it, we will be able to understand much more quickly what's happening in terms of variation. We will be able to say wheth- Illustration: MIKE CONNOLLY MULTIPLE INSTRUMENT CHAMBER a size of the Earth, none of its features would be more than 12.7 centimetres above the surface. Light entering the telescope will be reflected off the primary mirror to the secondary mirror 4.5 metres hatchlings will end up female. If. however, a cooling cyclone comes through at the critical time a third of the way through incubation of the eggs, at which time sex is determined, the beach will be covered in tiny males.

The discovery has also caused much debate about what is termed "head-starting" whereby eggs are taken from the wild and incubated in Eskys. The young turtles are then released, having avoided pre-dation on the beach, in an effort to restock the depleted Caribbean from which turtles were all but wiped out by the early mariners. Unfortunately most of the young turtles given this head start were probably males. Of course there is no reason why the natural sex ratio should not be skewed, given the lack of genetic control over sex determination. However, until recently, only the sex of mature male turtles muiH be distinguished in the wild.

An adult male trails behind it what Torres Strait islanders have christened a sword. Females and young males have tiny tails and are externally identical. The only option was to look inside. Limpus took a course in laparos-copy at a Melbourne hospital and then applied the technique to turtles. The gonads he saw revealed not only the sex of the animal the sex ratio proved to be pretty even but many of the secrets of the females sexual history.

An er there are different patterns of chromosomes which correlate with different areas and different types" of illness," Dr Kemp said. Plasmodium falciparum is many times smaller than the red blood cells in which it grows and its chromosomes are hard to see and count. The technique Dr Kemp's group used is a new method of separating different molecules of DNA, the molecules that compose chromosomes, by their lengths. The molecules are made to run in an electric field through a gel with cross-links like a net. Because the molecules are much longer than the holes in the gel, they must orient themselves end on to pass through the gel.

Every 80 seconds an electric pulse forces the molecules to make a 90 degree turn, so the longer the molecule, the slower it turns. All the molecules are therefore separated according to the time they take to pass through the gel. Dr Kemp said that similar studies have been carried out on try-panosomes, parasites that cause sleeping sickness in Africa. "These probably have at least 100 mini-chromosomes as well as some of similar size to the ones we have found," he said. Commenting on these developments in 'Nature', a parasitologist at London UniversityProfessor Frank Cox, said the application of the new and relatively simple technique represented a milestone in the modern study of parasites.

It would help scientists to understand how parasites can avoid destruction either by the body's defence systems or by drugs. ing lives in Australian waters. Then, in early 1984, came the immensely powerful Cyclone Kathy. Sweeping south-west across the Gulf of Carpentaria she lifted the sea confined between the Sir Edward Pellew islands and the coast and dumped it behind the mangroves. The water soon ran back to the sea but the turtles within it were stranded on the mud.

Limpus and Reed were part of a small rescue team called in by the Northern Territory Conservation Commission. Nearly two-thirds of the stranded turtles had been getting fat on the seagrass meadows offshore. Several of those returned by helicopter to the sea had been carrying tags from Raine Island. Predicting a big turtle year is useful. More importantly, for the first time anywhere in the world, it is now possible to calculate the size of the turtle population.

If two-thirds of the female turtles are preparing to nest it follows that the number of females in the population is one and a half times the number that do nest. The apparent synchrony of Heron and Raine islands is also impor rfe'T m- -x it rffitiiii tifftfffi field destroying every file on a tape. And only Tallgrass' new PCT has enhanced data integrity by adding the ability to correct errors from damaged tape. Just as you'd eXDect from the wor ri learipr in the HIGH On the north-eastern shoulder of Australia lies the remarkable Raine Island. As well as supporting the largest sea-bird breeding colony on the Great Barrier Reef it is also the nestling site for hundreds of green turtles every summer.

This last summer, however, it was different. There were not hundreds of turtles but thousands. On good nights you could have walked the entire kilometre circumference of the island on their backs without once touching the sand. The scene was chaotic. They dug up each other's eggs, they buried each other alive, they lumbered across most of the bird nests, they tumbled over the island's small cliffs and lay helpless on their backs.

It was the biggest green turtle nesting ever recorded anywhere in the world. Almost more remarkable than the scale of the nesting was that it had been predicted nearly a year earlier by Col Limpus. a research scientist working with the Queensland National Parks and Wildlife Service. In any year the number of turtles coming to nest varies as dramatically and unpredictably as a political popularity poll. Mr Lim-pus's correct prediction this year is yet another of many discoveries atwut the green turtle that have astonished biologists and are providing a sound basis for their own future management I He has succeeded by combining studies of the nesting beaches, -7 Edited by Philip Mcintosh Childless GIFT Doctors at the University of Texas ia San Antonio have developed a fertilisation technique which is simpler, and probably cheaper, than in vitro fertilisation.

A 37-year-old Scottish woman recently became the first to give birth through the technique when she delivered twins. Several similar pregnancies have been confirmed in Europe. In the new technique called GIFT (for gamete intrafallopian transfer), researchers remove mature eggs from a woman's ovaries and place them in her fallopian tubes with her husband's sperm. Fertilisation then proceeds naturally in the tubes and the embryo travels to the womb. "We are just putting things together at the right time and the right place," says Dr Ricardo Asch.

In the IVF method the eggs are removed and fertilised in a Petri dish; the embryo grows there for a few days and then is transferred to the womb. But GIFT will not replace the earlier "technique. According to Dr Martin Quigley, of the infertility program at the Cleveland Clinic, GIFT is best suited for cases of unexplained infertility when the sperm may not reach the egg or Nobody 'DOS' it better because nobody makes mass data handling as quick and efficient as Tallgrass Technologies' new integrated hard disktape subsystems. It's that simple. Because nobody but Tallgrass boasts enhanced disk systems (faster, easier to install, and delivering up to 80 Mb of Malaria vaccine research gets a shot in the arm of mass data handling.

Tallgrass' new PCT format is based on very where most turtle research has been conducted, with work on turtles in their own habitat, the sea. First he looked at growth rate. It was an established myth that turtles first begin breeding when six An adult green turtle swims over a reef where it forages for sea grasses and algae.Thev surface about every 10 to 30 minutes for air. but can stav submerged for hours. the egg does not get into the tube.

This accounts for up to 15 per cent of infertility. Dr Asch now plans a 12-month worldwide trial with about 500 women to determine GIFT'S success rate and the risk of multiple births or tubal pregnancies. Weather prize The American Meteorological Society's committee on tropical meteorology and tropical cyclones has made an award to an Australian meteorologist, Dr Greg Holland, for papers on tropical weather. Dr Holland, employed in the Bureau of Meteorology's research centre in Melbourne, is the first Australian to receive the Banner I. Miller Award.

The award consists of a plaque and a cash prize and is made for the best contribution to the science of tropical cyclone and tropical weather forecasting published in a journal with international circulation from July 1982 to June 1984. Dr Holland was selected for two papers. The first described a theoretical technique for interpreting some of the mechanisms responsible for tropical cyclone motion, and the other showed that the predictions from this technique were consistent with available observations. Dr Holland has been invited to Miami in January to receive his award at the annual meeting of the American Meteorological Society. a sound reasoning: so that you'll spend time putting your system to use, not giving it abuse.

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Five Oock.N.S.W 2046 Pimm KWIJUWlin -n-yinnt By philip Mcintosh SCIENTISTS at the Walter and Eliza Hall Institute have made a major advance in malaria research by identifying some of the basic genetic structure of the tiny malaria parasite, Plasmodium falciparum. Many different viruses and bacteria are understood at a genetic level, but until recently nothing of this kind has been known about minute animal parasites such as Plasmodium. In an article just published in 'Nature, a group led by Dr David Kemp at Melbourne's Hall Institute has reported research which shows that the malaria parasite has seven chromosomes in its single cell. Using a new technique pioneered at Columbia University, New York, Dr Kemp's group looked at strains of the parasite from a number of countries including New Guinea, Thailand and Ghana. "We found the same number of chromosomes in each strain, but the chromosomes vary dramatically in size from one strain to another," he said in an interview.

The significance of this variation is not clear, but it might be related to variations in the parasite and the development of drug resistance by Available from authorised)BM, Olivetti, Sperry and other fine personal computer dealers..