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Marsden Fund NewsletterNo 12 June 2000
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| Panel | No. of preliminary proposals | No. of invitations for full proposals |
|---|---|---|
| Biochemical & Biomedical Sciences | 126 (115) | 16 (17) |
| Cellular, Molecular & Physiological Biology | 158 (171) | 24 (25) |
| Ecology, Evolution & Behaviour | 189 (175) | 29 (23) |
| Earth Sciences & Astronomy | 83 (79) | 14 (13) |
| Humanities | 32 (37) | 8 (10) |
| Mathematical & Information Sciences | 61 (46) | 13 (13) |
| Physical Sciences & Engineering | 103 (119) | 18 (18) |
| Social Sciences | 82 (92) | 15 (15) |
| Total | 834 (834) | 137 (134) |
A team of marsden-funded physicists and astronomers is studying planets orbiting distant stars, known as exoplanets, using nearer stars as "magnifying glasses".
Observations are being carried out at the Mt John University Observatory by a group of researchers from Auckland, Canterbury and Victoria Universities, plus the Carter Observatory. Japanese astronomers are assisting with the work. The group calls itself MOA (Microlensing Observations in Astrophysics).
The team uses light to probe planetary structure, as shown. When two stars are aligned with Earth, light from the distant star is bent by the gravitational field of the nearer star. Einstein predicted this bending, and its observation early last century led to the acceptance of his theory of General Relativity.
The effect causes the distant star to appear brighter than normal. It is like looking at a distant candle through a magnifying glass; as the magnifying glass (the nearer star) passes between the candle (the distant star) and your eye (the Earth), the candle suddenly appears brighter.
"In collaboration with other international teams, we have extended the concept to include the bending effect of planets orbiting the intermediate star," explained Associate Professor Philip Yock from Auckland University.
"This small effect is detectable for pairs of stars that are very closely aligned with Earth. Such alignments are rare and brief, because all stars are in motion. Using large CCD cameras and large computers it is, however, possible to monitor millions of stars in a night to search for such alignments. This is what we have been doing since 1995, in partnership with other teams."
The search is now beginning to pay dividends. In July 1998, the New Zealanders and their American counterparts monitored an almost perfect alignment.
"In this event, bending was observed by both teams that is consistent with a low-mass 'terrestrial' planet in the habitable zone around the intermediate star. This is the first evidence of any kind for such an exoplanet," he explained.
The equipment being used in this work includes a telescope belonging to the University of Canterbury, and an electronic CCD camera supplied by the National Astronomical Observatory of Japan. The telescope was modified for the observations with grants from the Science Lottery Board, Auckland University and the NZ/Japan Foundation. The work was reviewed recently in Science.
With experience, scientists worldwide are improving their techniques, and further results may be expected soon. Dr Ian Bond, a Marsden Fellow in the MOA team, reported progress on the first search for an exoplanet in another galaxy at a recent conference in Cape Town.
"The ultimate goal of this work is to determine the fraction of stars with Earth-like planets. Other techniques being used by groups at Canterbury and Victoria Universities are capable of determining the fraction of nearby stars with gas-giant planets like Jupiter," Yock explained.
"The gravitational bending effect has other applications. In favourable circumstances, fine detail can be resolved on the surfaces of distant stars. In one case, our team and its partners resolved some detail on the surface of a star near the centre of the Galaxy, exceeding by a factor of more than 8000 the resolution of the Hubble Space Telescope. Subsequently, other teams improved on this by a factor of one hundred, on another star."
Yock says these are exciting times for astrophysics and related fields, with the origin of life, and indeed of the Universe, increasingly under the spotlight.
"On the local astronomical scene, an additional telescope from Japan is expected to be installed soon at Mt John. And just last month, the University of Canterbury became a founding partner in the Southern African Large Telescope (SALT), a 10m spectroscopic telescope to be built in South Africa during the next four years." For further information, contact Associate Professor Philip Yock, Tamaki Campus, The University of Auckland Phone: 649373 7599 ext 6838 Fax: 649308 2377 Email: p.yock@auckland.ac.nz Address: Private Bag 92019, Auckland
The principle of gravitational lensing. When a nearer star (centre) passes between a distant star (left) and Earth (right), the gravitational field of the nearer star causes the light to deviate slightly, making the distant star brighter than normal. Planets around the nearer star cause an additional, but tiny, deviation that also affects the brightness.
Some planet hunters at a recent meeting in Cape Town. From left: Phil Yock (MOA, Auckland), Debra Fischer (USA), Ian Bond (MOA, Mt John), Mine Takeuti (MOA, Japan), Jovan Skuljan (MOA, Canterbury) and Robert Bradbury (USA).
Printing and publishing used to be one of New Zealand's biggest industries and the huge infrastructure to support it was largely based in Otago. By the 1880s, the province had the biggest number of the country's printing establishments, and both papermaking mills were located there.
Marsden researchers Dr Shef Rogers and Dr Noel Waite are attempting to find out what made Otago such a dominant presence in the industry, to analyse how that success shaped the region, and to compare its history with that of other regions in New Zealand, Australia and Canada.
Their study of regional printing before 1920 is part of the Otago Print Culture Project led by Dr Rogers from Otago University's English Department. Dr Waite, a Marsden Postdoctoral Fellow, is assisting.
"In our first six months of work, we have documented Otago's impressive contribution to a national infrastructure of printing and publishing. Two of the three major trade journals of the 1890s emanated from Dunedin, and the region's legacy survives in the firms of Reed Publishing, Coulls Somerville Wilkie (whose name survives in the Whitcoulls chain), and John McIndoe Ltd," Dr Rogers explained.
"We have concentrated on the earlier period because the printing trade underwent rapid expansion in the second half of the nineteenth century. By some accounts, the printing industry and its allied trades was the third largest industry in the country."
According to the Government Gazette of 28 January 1887, there were 135 printing establishments in New Zealand in March 1885. Otago had the largest number of any province with just over a quarter of that total (36), eight more than its next rival, Auckland. Otago also monopolised the allied trade of papermaking, with both mills located there.
"While industrial relations within the region were comparatively amicable, the rapid transition to mechanised production served to create a ruthlessly competitive industry," Dr Rogers added.
"Otago was not immune and the exploitation of partially skilled and child labour to underwrite low costings increased. Although the labour question was considered as part of the 1890 Sweating Commission, many employers had already recognised that such business practices were unsustainable and decided to follow the example of their workers and combine."
The establishment of the Otago Master Printers Association and a tariff of minimum prices in 1889 was a critical first step in addressing these problems. An early advocate of national federation, they also championed the adaptation of the Typothetae in 1906, an American system involving the registration and balloting of tenders in order to maintain prices.
"Comparable systems were later established in Australia, and in some cases led to allegations of price-fixing and monopolistic behaviour. However, in the Dunedin and regional context, they had the effect of stabilising and consolidating the industry, as well as allowing for fair wages to be paid to workers," he said.
"Further work remains to be done on how the ensuing debates over free trade versus protectionism (debates that sound remarkably familiar to contemporary ears) affected Otago's national and international presence in the printing world.
"But our preliminary results make it clear that the printing and publishing industries made important intellectual and valuable economic contributions to the region."
The project is one of several funded through Marsden grants to contribute to
the national History of Print Culture in New Zealand research programme. Initiated
in 1994 by the Humanities Society of New Zealand/Te Whaainga Aronui, the programme
is hosted by the Alexander Turnbull Library.
For further information, contact Dr Shef Rogers, Department of English, University
of Otago Phone: (03) 479 8892 Fax: (03) 479 8558 Email: shef.rogers@stonebow.otago.ac.nz
Address: PO Box 56, Dunedin
Otago binders at work around 1905.Reproduced from Peter J. Stewart, Type of a century: 100 years of trade unionism in the printing industry in Otago (Dunedin, Otago Branch of the N.Z. Printing and Related Trades Industrial Union of Workers, 1974).
Marsden researchers from Otago are at the vanguard of global work on mysterious electrical discharges known as "red sprites".
The team of physicists, consisting of Professor Richard Dowden and Drs Craig Rodger and James Brundell, recorded the first ground-based video images of these elusive high-altitude discharges outside the United States. The Otago researchers' theories of the composition of these elusive phenomena are now gaining currency worldwide.
First discovered in 1989, red sprites are believed to be produced by discharges racing from the top of thunderclouds, often about 10km high, to the base of the ionosphere, 90km up. The high-altitude sprites apparently follow immediately after much more easily visible cloud-to-ground lightning strikes.
"From 1995 on we have been actively involved in research on red sprites, first in the mid-western USA and, since 1997, in Australia's Northern Territory, supported by Marsden," Craig Rodger explained.
In the USA, the team operated very low frequency radio receivers and collaborated with American scientists on optical experiments.
"In our first two years of operation we showed that red sprites affected very low frequency radio transmissions, due to large changes in ionisation levels in the lower ionosphere. Initially our conclusions on red sprite ionisation levels were not accepted by the wider community," Dr Rodger continued.
"Measurements of the optical spectra of red sprites appeared to indicate no significant levels of ionisation. But advances in optical research techniques over recent years have helped confirm the existence of large amounts of ionisation in the lower parts of red sprites.
"Red sprite produced ionisation is clearly structured on ~100m scales, probably associated with the structure seen in the optical pictures. In 1997 our campaign produced the first ground-based red sprite observations made outside the USA, and showed that there is little to distinguish the red sprites observed near Darwin from those in America.
"Our optical images were captured by a Russian (supposedly ex-KGB) image intensifier whose output was recorded on a video camera. This was about a tenth of the cost of the camera systems used by most red sprite researchers, but produces images of similar quality."
The discovery of red sprites dates back to the day in 1989 when a group of researchers from the University of Minnesota were testing a sensitive TV camera system intended for flight on a high-altitude rocket. The camera was recording the star-field above a distant thunderstorm, occurring on the edge of Lake Superior.
The camera observed a twin upward flash apparently originating in the distant cloud tops lasting for two TV frames. The phenomena now termed a "red sprite" had been captured for the first time. We now know that red sprites are a relatively common event.
The reddish luminosity appears highly variable from sprite to sprite some are "carrot" or "plume" shaped, others appear as groups of luminous semi-vertical columns, and some bear a striking resemblance to enormous jellyfish. They are about 10100km wide and stretch from about 45km to 85km in altitude.
"Red sprites are short-lived, with durations of 1/100th to 1/10th second. The discovery of red sprites provided an explanation for observations we have been making since the late 1980s," said Dr Rodger.
"For many years we have monitored transmissions from large, high power, communications transmitters operating at very low frequencies. These transmitters exist primarily for military communication and navigation, and serve as 'standard candles' through which we observe changes in the lower ionosphere.
"For example, we have frequently observed disturbances in the transmissions of the US Navy transmitter near the North West Cape of Australia, which are associated with lightning discharges. Indeed, back in 1988 we suggested that these might be produced by 'stalactites' of ionisation poking down from the lower ionosphere red sprites appeared to meet this idea."
Dr Rodger says there is still much to learn about red sprites. "Many of the fundamental properties are still under dispute, as is the mechanism by which they are created. Red sprites occur in a region of the upper atmosphere which is relatively hard to probe far too high for balloons or aircraft, and too low for satellites.
"Other than very short term (and locally disruptive) rocket measurements,
investigations of the upper atmosphere have been mainly restricted to electromagnetic
probing at low frequencies. Red sprites provide another way to investigate what
is happening at these altitudes, and help us understand the coupling of thunderstorms
to the upper atmosphere." For further information, contact Professor
Richard Dowden from LF- EM Research Ltd Phone: (03) 473 0521 Fax: (03) 473 0526
Email: dowden@physicist.net Address: 17 Dunedin/Waitati Hwy, Pine Hill, Dunedin,
9001
Red sprite observed over Australia, south of Darwin, in 1997.
Marsden researchers have found that the strong easterly wind that often blasts the Mackenzie Basin in the afternoon is caused by the mountain region heating up and sucking in air from the surrounding plains.
A three-year project led by Associate Professor Andrew Sturman of the Geography Department at the University of Canterbury involved the gathering of field data from a network of weather stations, balloon sounding systems, sodar (acoustic radar) and an instrumented aircraft. A sophisticated modelling study was also undertaken.
A team of scientists from New Zealand, Canada and the United States had input into this major atmospheric research programme.
"People have long suspected that the easterly which enters the basin during the afternoon was either a sea breeze originating from the coast or is the intrusion of the well-known Canterbury north-easterly. In meteorology, winds are usually named after the place from where they originate, so an appropriate name for these easterly intrusions is the Canterbury Plains Breeze (CPB).
"Our results so far show that the key mechanism responsible for generating the CPB is the Mackenzie Basin acting as an elevated heat source, drawing air from outside through passes and gaps in the eastern foothills," Professor Sturman explained.
"Factors that affect the daytime heating rate of the basin, such as soil moisture, have a dramatic impact on its generation. We found that when the area is influenced by high-pressure weather systems, locally generated up-slope and up-valley winds dominate the flow in the basin in the morning and early afternoon. These interact with a circulation system generated by Lake Tekapo.
"The afternoon arrival of the CPB disrupts these localised winds and is a major feature of the climatology of the basin. It has the potential to carry pollutants and dust from the surrounding plains and adversely affect the air quality of this pristine area, with its well-established tourism industry."
The mechanism that generates the region's wind systems became the focus of a computer modelling study conducted by Peyman Zawar-Reza, a PhD student supported by the Marsden grant.
The model was able to simulate the CPB, with reasonable accuracy in predicting its wind speed, wind direction, and times of onset and cessation. To determine the mechanism(s) responsible for the generation of CPB, the simulations were repeated with changes in key parameters.
For example, when the ocean around the South Island was removed from one of the computer runs, the CPB was still evident, although with a minor reduction in wind speed, showing it is not a sea breeze intrusion into the basin.
"Locally generated winds, such as sea and land breezes, and mountain and valley winds have been studied by scientists for more than a century. Knowledge of these wind systems is important for a variety of practical applications such as aviation, air pollution and agricultural meteorology," said Professor Sturman.
"However, the local flows in the Mackenzie Basin are frequently disrupted later in the day by a persistent, strong wind intruding through the mountain gaps and passes from the east, which was observed at some weather stations well into the evening. Winds with similar characteristics have been the focus of recent studies in Washington State and Mexico City, where attempts are being made to explain their characteristics and model them because of the implications for air pollution dispersion."
Professor Sturman said the combination of field and modelling approaches to this problem had advanced understanding of the nature of airflow in the complex terrain common in New Zealand.
"It also provides the knowledge base required to address a number of contemporary environmental problems, such as the dispersion of air pollution and wind blown dust," he said. For further information, contact Associate Professor Andy Sturman at the Department of Geography, University of Canterbury Phone: (03) 364 2502 Email: a.sturman@geog.canterbury.ac.nz Address: Private Bag 4800, Christchurch
Researcher Stuart Powell from Victoria University helps in the gathering
of field data.
