Catherine Corrigan Catherine Corrigan Catherine Margaret Corrigan (born 1972), often known as Cari Corrigan, is an American scientist best known as a curator of the meteorite collection at the Smithsonian Institution. She is a scientist in the Department of Mineral Science at the National Museum of Natural History. Corrigan obtained a Bachelor of Science in 1995 and a Master of Science in 1998, both in Geology at Michigan State University. Her master's thesis was titled "The Composition of Impact Breccias from the Chicxulub Impact Crater, Yucatan Peninsula, Yucatan, Mexico". She later earned a Ph.D in Planetary Science at Case Western Reserve University
Impact crater describe what are now recognised as impact-related features on Earth. The cratering records of very old surfaces, such as Mercury, the Moon, and the southern highlands of Mars, record a period of intense early bombardment in the inner Solar System around 3.9 billion years ago. The rate of crater production on Earth has since been considerably lower, but it is appreciable nonetheless; Earth experiences from one to three impacts large enough to produce a 20 km diameter crater about once every million years on average. This indicates that there should be far more relatively young craters on the planet than