The 24th General Assembly of the International Astronomical Union, held in Manchester from 6-18 August 2000, was attended by a record number of African Space Scientists. There were 14 IAU members and 4 invited participants from Algeria (2), Egypt (3), South Africa (11), Zambia (1) and Zimbabwe (1). During the Special Session on Astronomy for Developing Countries, the session chairman, Prof Alan Batten, attributed this growth in African participation to our Working Group.
In spite of the promising (modest) growth in the number of African participants, there is still a very serious dearth of African members of the IAU. The advent of large-scale facilities such as SALT, HESS and the World Space Observatory, coupled to increasing internet access, presents unprecedented opportunities for the sustainable development of space science in Africa. This should lead to a steady growth in the numbers of African participants at future IAU general assemblies.
The importance of impact cratering (by asteroids, comets, and large meteorites) and the potential danger that it represents to mankind has, in recent years, been widely publicised and debated. Most recently, the British parliament held a debate dedicated to this issue and resolved that more efforts had to be made to detect potentially earth-orbit crossing asteroids and comets. American and British projects, such as Spaceguard, have already been highly successful in identifying a large number of previously unknown Near-Earth Asteroids and other, possible, threats. NASA's Shoemaker-NEAR (Near-Earth-Asteroid-Rendezvous) mission has already provided an enormous amount of previously unknown information about the nature of asteroids, and will continue to do so until the mission comes to an end in 2001. The international impact cratering community has made major efforts to arrange for a deep-drilling program into one of the world's largest impact structures, the 65 million year old Chicxulub impact structure off the Yucatan peninsula in Mexico. And European and African (from Ghana and South Africa) scientists are working towards a drilling investigation of the 10 km wide, complex meteorite crater Bosumtwi in Ghana.
To date, 19 impact structures are known from Africa. Most of them are located in Saharan Africa and were discovered in the course of oil exploration around the mid-20th century. Others are known from southern Africa, and in part have been known for many decades but were hotly debated as being of impact or some other geological origin. Much work on these structures has been carried out over the past 20 years at the University of the Witwatersrand (Wits) in Johannesburg. In 1999 many new impact cratering related results were presented at the 62nd Annual meeting of the Meteoritical Society in Johannesburg, Gauteng, the "city of gold". On that occasion, the first dedicated African Impact Cratering Research Group (ICRG), founded shortly before by Wits University, was presented to the international community. Since then, workers at the Wits Geology Department, the Hugh Allsopp Isotope Laboratory, and at the University of the North West - collectively forming the ICRG, have been tremendously active. More than 20 research articles, partially in close collaboration with researchers in Europe and the United States, have been published. The group continued work on the world's largest known impact structure, the Vredefort Structure which incorporates the gold-rich Witwatersrand basin, Bosumtwi in Ghana, and the 70 km-wide impact structure Morokweng in North-West Province of South Africa. Following a first report at the Meteoritical Society conference by geologists from Botswana of an interesting crater structure in the eastern part of that country, the 2.5 km-wide Kgagodi impact crater was confirmed and presented to the planetological community at the 2000 Meteoritical Society conference in Chicago. The Kgagodi impact crater has the potential to provide a significant, rather long palaeo-environmental record, should it be possible to drill into this structure in its center and to obtain a complete drill core through the sedimentological crater fill. This is a very important prospect for the international global change programme.
The ICRG successfully presented a proposal to participate in the Chicxulub drilling project and now hopes that this multinational investigation will be successfully started. In July 2000, the 4th Snowbird Conference, titled "Impacts and Beyond...." took place in Vienna, and the ICRG team participated with three delegates, who presented talks on the African impact cratering record and the South African sections across the Permian-Triiassic boundary, which demarcates the time at 250 million years ago, when by far most lifeforms became extinct in a relatively short time. It is hotly debated whether this mass extinction, like that at the Cretaceous-Tertiary Boundary at 65 million years ago, could be the result of a catastrophic impact event as well. Experimental work towards the understanding of shock metamorphic micro-deformation in the very resistant (to weathering and metamorphism, for example) mineral zircon has also been conducted, in collaboration with Austrian and German scientists. Clearly, the impact cratering community - and the ICRG workers - deal with a multi-disciplinary subject, involving astronomy and earth science disciplines such as sedimentology, geochemistry, mineralogy, and palaeontology, inter alia.
Besides being busy with these and a few other projects, the ICRG is engaged in meteorite research. Meteorites, in South Africa, are strictly protected by the government, and permits are required even to study them. The ICRG has obtained the only permit yet issued in South Africa granting permission to "damage meteorites for the purpose of their proper identification and classification". "Damage" here, of course, means that small samples may be extracted for mineralogical or geochemical analysis. It is therefore possible to contact the ICRG with any find which may be thought to represent a meteorite and request to have the specimen identified. So far, a number of "meteo-wrongs" have been studied, but in due course the "real McCoy" (meteo-rights) will appear. There must be thousands of meteorites lying on the surface of the African continent - at least some of which will be of great scientific and educational value and still have the potential to make major contributions to our understanding of the formation and evolution of the Solar System.
The ICRG is dedicated to state-of-the-art research on impact crater structures and meteorites, but not only within the South African context. Collaboration with other countries in Africa is encouraged and desirable, and the members of the research group look forward to contacts (address details are given below) from all parts of Africa. Many analytical facilities are available to the ICRG, but should it not be possible to assist with analytical work in South Africa, contacts with all other parts of the world do exist. It is also possible to assist with setting up direct research links between African and overseas researchers.
| Professor Wolf Uwe Reimold Head: Impact Cratering Research Group Department of Geology University of the Witwatersrand Private Bag 3 P.O. Wits 2050 Johannesburg South Africa |
Tel. +27 11 717 6565 Fax +27 11 339 1697 E-mail: 065wur@cosmos.wits.ac.za |
On 1 September 2000, international and local partner and scientists, as well as other dignitaries attended the ground-breaking ceremony to mark the official start of construction of the Southern African Large Telescope (SALT) at the South African Astronomical Observatory (SAAO), near Sutherland in the Northern Cape.
Funding partners from five countries joined Dr Ben Ngubane, South Africa's Minister of Arts, Culture, Science and Technology in digging into the rock-hard soil where SALT will be built over the next four years. Germany, New Zealand, the UK, Poland and the USA are all committed to supporting Africa's quest for a giant eye to the universe. The international representatives described SALT as a bold step into the future and wished South Africa every success with the construction phase lying ahead.
"It is with great national pride that we stand here today to witness the turning of the sod of what will be the most powerful telescope - not only on the continent of Africa, but in the entire southern hemisphere," said Minister Ben Ngubane. "Such a telescope will provide a focus for the development of basic sciences on the African continent," he said.
"The new telescope will have two primary objectives - to do cutting-edge physics, and to change the fortunes of the country," said Dr Khotso Mokhele, President of the National Research Foundation (NRF). The NRF is the official South African SALT partner, with funding provided by the Department of Arts, Culture, Science and Technology (DACST).
Minister Ngubane expressed the hope that SALT would be a significant catalyst in producing more black post-graduate students in science and engineering. The great economic and educational benefits expected from the project were emphasised throughout the day.
The local community of Sutherland is positioning itself to become a popular tourism and science destination. Earlier in the day, a twinning agreement was signed between Sutherland and Fort Davis in Texas, USA. Fort Davis is home to the Hobby-Eberley Telescope, which pioneered the design being used in SALT.
Exactly the right thing, at the right time and in the right place. That was the overwhelming feeling at the ground-breaking ceremony.
On April 27, mysterious glowing objects began falling out of the Western Cape sky. The largest fell on a farm about 37 km NE of the centre of Cape Town, only 13 km from the centre of the suburb of Durbanville. Another landed about 70 km further ESE at Lemoenpoort (100 km ENE of Cape Town and 25 km south of the town of Worcester). A third hit the ground another 24 km further ESE, near the town of Robertson. The story about the Lemoenpoort "space ball" broke first, with 15-year old Theodore Solomons telling how a "glowing hot" ball "came out of nowhere, straight at me. It didn't come from straight above, but at an angle. Then I ran away and I heard something like two gunshots when the ball hit the ground only meters away, but it didn't make much of a dent". It was still too hot to touch half an hour later, when farmer Pieter Viljoen arrived. Labourers in his vineyards had told him about a shining ball that hit the ground 50 m from where they were working, and as soon as it was cool enough he loaded the mysterious intruder into his bakkie (pickup truck) for storage in his barn. It eventually ended up being investigated by the Department of Civil Aviation at Cape Town International Airport, who soon realized this was not part of any known aircraft.
Chris Koen at SAAO found himself fielding media calls the next day, with the media apparently reasoning that astronomers ought to know about things that come from the sky. After a hasty consultation with retired SAAO astronomer and satellite-tracking hobbyist Greg Roberts, Chris was able to suggest various bits of orbital debris that might conceivably have come down to earth that day.
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But the story didn't die, as over the weekend newspapers began reporting the landing of a much bigger, oblong object on Buurmanskraal, Philip Scher's farm, near Durbanville. Neighbour Lampies Lampbrecht heard "a sort of crack and then an explosion", and some of his farm workers saw the glowing "ball" land on Scher's farm a short distance away. Lampbrecht said it looked like a 3000-litre water tank. Monday, 1 May, was a holiday, but SAAO's Dave Laney found himself rousted out of bed by media calls about this latest rusty intruder from outer space, which early reports said had fallen a day after the first "space ball". A bit of hasty web research showed that a suspiciously similar object had fallen near Georgetown, Texas on January 22, 1997 - a propellant tank from the second stage of a Delta II rocket. A team of e-tv reporters who arrived for an interview later in the day looked at the web page picture and immediately identified the Durbanville "spaceball" as almost identical to the Texas object, in size, shape and appearance. Alan Pickup in Edinburgh quickly posted an analysis giving the likely culprit as the Delta II second stage rocket from the launch of a GPS satellite in March 1996.
It was predicted to decay around the time when eyewitnesses reported the various falling objects (between 1300 and 1330 UTC), and it was over the Cape at the right time. New interviews by reporters established that all objects had in fact fallen on the same day at roughly the same time.
On May 3, a report previously buried in a local newspaper reached Cape Town. The Afrikaans newspaper "Die Burger" reported that Bertie Nel, manager of Le Grande Chasseur wine cellar near Robertson, had heard a noise "like a helicopter", then looked up to see a glowing object apparently 150 m up and falling fast. About a second later it had made a dent in the yard of Wouter de Wet some 200 m away, splashing hot metal as it landed. A piece of what looked like rubber appeared to be melting in the heat. This was the "thrust chamber" (exhaust nozzle), "about as large as a 20-litre drum" It hit the ground at 1530 SAST on April 27, farthest east along the track of the orbiting rocket stage and presumably last to land.
Reports and pictures matched what would be expected if these were bits of a Delta II second stage, but it was time for a personal view. The first close encounter was at the Kraaifontein police station's vehicle pound, where Case Rijsdijk and Dave Laney of SAAO photographed the main propellant tank. Captain Jane Cohen was more than willing to deliver it to SAAO for safekeeping the next day. Sightseers kept arriving to see the "space ball", and the vehicle pound offered no protection from rain. The Robertson police were just as happy to give up the exhaust nozzle, providing Case drove out to fetch it. It took a bit more persuasion to get the civil aviation authorities to give up the Worcester object, which proved to be one of the pressurisation spheres mounted around the base of a Delta II second stage. After a short stay in SAAO's mechanical workshop, the objects went on display in Cape Town's new MTN ScienCentre.
Nobody was hurt by the falls in the U.S. or South Africa, though a bit of "gauze" hit a woman in Oklahoma. So far the only "sky is falling" casualty is a Cuban cow hit by another piece of American space hardware years ago. The propellant tank definitely took some hits in orbit before falling on South Africa, however. Photographs show a number of micrometeorite pits from small bits of debris. Even a fleck of paint can make a surprisingly large dent when travelling at 30 000 km/h.
Japanese and South African astronomers are about to start putting together a clearer, sharper picture of the two nearest galaxies to our own (the Magellanic Clouds) and of the central regions of our own Milky Way galaxy. These will be the main targets of surveys with the new InfraRed Survey Facility (IRSF), officially opening on Wednesday 15 November 2000.
The IRSF is the seventh telescope on the South African Astronomical Observatory (SAAO) observing site near Sutherland in the Northern Cape, and the second largest there, with a mirror 1.4-metres in diameter.
"Japan and South Africa have long been partners in building and using infrared cameras for astronomy. This international partnership resulted in the new computerised, hi-tech facility at Sutherland, ushering in an exciting new era for infrared astronomy," says Dr Khotso Mokhele, President of the National Research Foundation (NRF). Mokhele officially opened the facility with Prof Shuji Sato, Principal Investigator and Head of the Infrared Group at Nagoya University, Japan.
"We can't see infrared radiation, but we may feel it as heat. At these wavelengths we can 'see' through dust clouds to regions otherwise hidden from our view," explains Dr Bob Stobie, Director of the South African Astronomical Observatory (SAAO). "Infrared light is also ideal for studying cool stars that radiate most of their energy at wavelengths too long for the eye to see," he says.
To date, collaboration between Japanese and South African astronomers for infrared observations has mainly involved the 0.75-metre telescope at the SAAO's Sutherland site and a small 0.4-m telescope at the SAAO in Cape Town.
The total construction cost of the IRSF is about R18 million (US $2.25 million). The SAAO is responsible for the building (R1.1 million), infrastructure and continuing support. Major funding came from the Japanese Ministry of Education. Nagoya University in Japan built the infrared camera (SIRIUS) at a cost of R7 million. University staff worked with an optical company at Kyoto to build the telescope (R10 million), using Russian optics.
In each infrared survey exposure at Sutherland, an area of the sky (a square about one quarter as wide as the full moon) will be recorded in three different infrared wavebands simultaneously. Previous infrared surveys have covered large areas of sky, while the Sutherland project will record fainter objects, in images four times as sharp.
The 10th UN/ESA Workshop on Basic Space Science, titled "Exploring the Universe - Sky Surveys, Space Exploration, and Space Technologies," will be hosted by the University of Mauritius from 25 to 29 June 2001.
In 1900, the United Nations, in cooperation with the European Space Agency, initiated the organization of annual Workshops on Basic Space Science as part of the Programme on Space Applications of the United Nations Office for Outer Space Affairs. These Workshops, focusing on planetary exploration and astronomy, have been held in India (1991) and Sri Lanka (1995) for Asia and the Pacific, Costa Rica (1992) and Honduras (1997) for Central America, Colombia (1992) for South America, Nigeria (1993) for Africa, Egypt (1994) and Jordan (1999) for Western Asia, and Germany (1996) and France (2000) for Europe.
This Workshop is the 10th in the series of UN/ESA Workshops on Basic Space Science and will be oriented to the opportunities for developing countries to participate in world space observations and in the utilization of space technologies. Efforts will focus on sky surveys, breakthroughs in space science/technology and the studies of the universe. Emphasis will be placed on data manipulation techniques (including data reduction, archiving, retrieval, etc) and multi-wavelength analysis.
The programme of the Workshop will comprise:
Updated information about the Workshop series can be obtained via
the World-Wide-Web
at
http:// www.seas.columbia.edu/~ah297/un-esa/.
Indication of Interest deadline is 1 May 2001
WGSSA