High Quality Content by WIKIPEDIA articles! Dr. H. Jay Melosh (born June 23, 1947) is an American geophysicist, renowned as an expert on impact cratering. He earned a degree in physics from Princeton University and a doctoral degree in physics and geology from Caltech in 1972. Dr. Melosh`s research interests include impact craters, planetary tectonics, and the physics of earthquakes and landslides. His recent research includes studies of the giant impact origin of the moon, the K/T impact that extinguished the dinosaurs and the ejection of rocks from their parent bodies. He is also active in astrobiological studies that relate chiefly to the exchange of microorganisms between the terrestrial planets (a process known as panspermia, or in his terms transpermia ). In 1989, Oxford University Press published his book "Impact Cratering: A Geologic Process" (ISBN 0-19-510463-3)