236 SOLAR SYSTEM/Meteorites The Twentieth-Century Revolution in Meteoritics Up to the orbital flight of Sputnik heralding the space age in 1957, the study of meteorites was a quiet museum occupation The scientific interest in meteorites then exploded because of what they might tell us about planets, satellites, and asteroids By coincidence, the year of Apollo XI, 1969, saw a Japanese party find nine meteorites on an area of bare ice in the Yamato Mountains Antarctica This  10 km area subsequently yielded 1000 meteorites Blue ice areas and moraines in Antarctica have now yielded approximately 30 000 specimens representing some 20 000 falls Two principle factors produce the optimum conditions for recovery: weathering is virtually nil in the arid climatic conditions and low temperatures prevailing, and the ‘conveyor belt’ situation on the ice sheet, snow falling and being buried and compacted to ice together with any meteorites on the surface, the snow moves coastwards and where nunataks (rocky peaks) obstruct its passage, the entrained and buried meteorites are excavated by wind action which removes the ice above (Figures 15 and 16) By coincidence again, in the 1960s, rabbit trappers kept bringing in meteorite finds strewing the limestone surface of the arid Nullarbor Plain in Western Australia, and the writer of this entry, then working at the Western Australian Museum, wrote prophetically, ‘‘that the Nullarbor Plain must be littered with meteorites of all types’’ This was indeed so and systematic collection has so far yielded about 300 individual meteorites including two shower groups of more than 500 meteorite masses Other desert areas of the world were then searched and Libya, Algeria, Morocco, and Oman have yielded several hundred finds, while desert areas in Roosevelt County, New Mexico have also proved productive Neither Antarctica nor the desert areas are ‘worked out’ and many more finds will undoubtedly be made in the next years of this century There are some desert areas in Asia, including the Gobi, that are not even searched so far, but a reconnaissance in the Gobi proved disappointing State-of-the-Art Research Meteoritics is a major area of scientific research nowadays and as many as 500 scientists may attend the yearly meetings of the Meteoritical Society Research topics are extremely varied and besides such related topics as impact processes; tektites; planetary, lunar, satellite, cometary, and asteroid exploration, topics bearing directly on meteorites may include: Ca-Al rich inclusions (CAIs) in meteorites, believed to be survivals from the accretion of the Solar System Isotope fractionation in pre-solar graphite in carbonaceous chondrites Isotope studies of chondrules and CAIs Modelling conditions for the launch-window of ?Martian meteorites Aqueous alteration of carbonaceous chondrites Presolar nano-diamonds in meteorites Xenon isotopes in nano-diamonds Trapped gases in ordinary chondrites Trace elements trapped in lunar meteorites Figure 15 A meteorite as found on blue ice, its position flagged, Antarctica (from McCall 1999, reproduced with permis sion of Palgrave Macmillan) This random sample illustrates the diversity of research: the revolution in meteoritics described above has produced enough subject material to keep science busy for many decades, if not centuries, and more keeps coming in The important point to remember that meteorites come in free of charge – they have been called the poor man’s ‘space probe’ Even the cost of searching after major bolide events, searching Antarctica and systematic searching of the