May 21, 2019,
3:30 p.m. - 4:30 p.m.
Meteorites are time capsules of planet formation. The most abundant meteorites types originate from primitive bodies that never heated to the point of differentiation and contain chondrules, which were transiently molten silicate spherules. These primitive planetesimals formed contemporaneously with planets over the first few million years of the solar system. There is no consensus on the physical processes that formed chondrules and assembled them into planetesimals. Impact processes have been proposed many times but have been criticized as inconsistent with observations. I will present a new physical model for the formation of chondrules and chondrites based on previously unrecognized phenomena during high-velocity collisions between planetesimals. The model links the origin of chondrites to the dynamical excitation of planetesimals from the giant planets. I propose that the uncertain history of our giant planets, their formation locations and migration distances, was recorded by planetesimals that have been preserved in the asteroid belt. Meteorites are the Rosetta stones of planet formation that can relate the history of planetesimals to the history of the giant planets.