Abstract: Dust from the deserts. Smoke from wild fires. Pollution from developing economies. These are some of the components of the Earth's aerosol system. Aerosol particles from these different sources affect human health and play a role in climate forcing. The particles also modify clouds, the hydrological cycle and affect atmospheric circulations and weather. In fact aerosols and clouds are so closely linked that we may think of them as one continuous system. The global aerosol system is highly variable in space and time, and thus to characterize these particles we need a variety of observational and modeling tools. One set of tools are the constellation of satellites currently observing the earth and providing a continuous stream of data that we are only beginning to exploit. It is time to use the data in a variety of ways to learn something about aerosols and clouds, and to try to answer some of the most pressing scientific questions that we have concerning climate change and air quality. During this seminar I will provide an introduction to how we retrieve aerosol and cloud information from the satellite radiances, what satellite products are available that focus on atmospheric variables, what are the limitations of these data, and a survey of the many ways we use satellite data to learn about our planet.