Topic: Earth's atmosphere

This seminar examines comet impacts during the dispersal of the outer Solar System's planetesimal disk. Instability among the giant planets sent some bodies toward the terrestrial planets. Noble gases preserved in Earth's atmosphere provide evidence for the scale of this bombardment and help relate its timing to the growth of Earth.

This lecture examines the composition of Earth's atmosphere and how it is reconstructed through time. It distinguishes abundant nitrogen and oxygen from trace gases whose concentrations respond strongly to human emissions. Measurements are used to compare natural changes with human influences relevant to climate.