Peter Goldreich, Emeritus Professor at the Institute for Advanced Studies, Princeton, and Emeritus Lee A. DuBridge Professor of Astrophysics and Planetary Physics at the California Institute of Technology, will visit the Institute of Sciences of the Cosmos at the University of Barcelona, on Monday, October 28, 2013.
He will give a colloquium entitled “Reading the Record of Ancient Impacts”, at the Aula Magna of the Faculty of Physics of the UB, at 12:00.
Professor Goldreich is well known for his pioneering work on the origin of planetesimals, the alleged precursors to fully-fledged planets. He also studies the important problem of the migration of planets. The Kepler satellite is discovering thousands of extrasolar planets, with a rich variety of properties, often drastically different from those of the solar system planets, and in contradiction of basic ideas about planet formation. An important example is the existence of so-called "hotJupiters’’, very massive planets found to orbit extremely close to their star. Models of planet migration, as those proposed by Professor Goldreich, address these challenging problems presented by the Kepler’s ever growing sample of extrasolar planets. Professor Goldreich’s most recent research turns to Earth to look for a new kind of evidence of the process of formation of the solar system: impact spherules. The main topic of his colloquium, impact spherules are the leftovers of asteroid impacts on Earth. When a fragment of an asteroid hits the Earth, the impact vaporizes ambient rocks generating a vapor plume,also known as a fireball. The cooling of the fireball results in the formation of nearly spherical droplets of molten rock, known as impact spherules. Theoretical physicists, like Professor Goldreich, develop models that allow them to derive the size of the asteroid (from the thickness of the spherule layer deposits) and the velocity of the impact (from the size of the spherules).
Professor Goldreich is one of the most accomplished and diverse theoretical astrophysicists. He is the recipient of the 2007 Shaw Prize, also known as the "Nobel Prize of the East’’, for his achievements on theoretical astrophysics and planetary sciences. Earning his PhD from Cornell University in 1963, he was an Assistant Professor of Astronomy and Geophysics at the University of California, Los Angeles, between 1964 and 1966, and became Associate Professor at the California Institute of Technology in 1966, and then Full Professor in 1969. He has also been a professor at the prestigious Institute for Advanced Studies at Princeton since 2005. His work has led to profound contributions in our understanding of the rotation of planets, the dynamics of planetary rings and planet satellites, the spiral arms of galaxies, the oscillations of the sun and white dwarfs, the nature of pulsars, the physics of turbulence in magnetized fluids, and the origin of planets.
