Why are so many meteorites found in deserts?
Deserts are dry, so meteorites rust very slowly and can survive for tens of thousands of years. Sparse vegetation and pale ground also make dark stones easy to spot.
Meteorites land everywhere, but in most places they vanish quickly. Rain, damp soil and plant roots attack the iron metal and minerals inside them, so in a wet climate a stony meteorite may crumble or become unrecognisable within decades to a few thousand years. Deserts slow that destruction dramatically.
With very little rain, chemical weathering happens at a crawl. Meteorites in hot deserts can survive on the surface for tens of thousands of years, and in exceptionally dry places such as Chile's Atacama Desert some have lasted far longer. That means a desert surface slowly accumulates meteorites from many thousands of years of falls.
Deserts also make finding them easier. There is little soil, grass or forest to hide them. Many desert surfaces are deflation surfaces or gravel plains, where wind has blown away fine sand and left a layer of stones. A dark, crusted meteorite can stand out clearly against pale limestone, sand or salt flats. Searchers can drive slowly or walk long distances, scanning wide areas.
Since the late 1980s, and especially from the late 1990s, the Sahara has produced thousands of meteorites, many labelled NWA (Northwest Africa) when their exact find site is unknown. Oman, Libya, Algeria, the Nullarbor Plain in Australia, and dry lake beds in the United States have also been rich sources. These finds have brought to light rare treasures, including many lunar and Martian meteorites. Desert meteorites do show their age: crusts darken or wear away, and metal turns brown with rust. Scientists grade this with weathering scales. Before searching any desert, remember that laws differ greatly between countries; some ban collecting or exporting meteorites entirely, and you always need permission to search land.