I spend most of my time looking for and intensely studying the small icy objects at the edge of our solar system, in the Kuiper belt. These Kuiper belt objects are fascinating to me in two ways. First, as the debris left over from the formation of the solar system, they are a fossil record of the very earliest history of the planets. The bodies in the Kuiper belt tell a history of rapid accretion, quiescent growth, violent perturbation, and giant impacts, all tied to the growth of the giant planets. Trying to understand solar system history by looking only at the small number of remaining planets is hard, but the imprint left on the thousands of objects in the Kuiper belt is a fossil record that we can slowly piece together. The tools used for this forensic work include large surveys with facilities like the Subaru telescope on Mauna Kea and also massive dynamical simulations that explore different possibilities for the formation and evolution of the solar system.
In addition to being simple dynamical tracers, some of these objects in the outer solar system ‚ particularly the largest ones , are fascinating worlds in their own right. We are trying to understand the basic geophysics of large icy bodies by studying atmospheric creation, surface chemistry, interior differentiation, and impact resurfacing on these bodies, all by gleaning observational hints from telescopes like Keck, Hubble, and CARMA.
As a hobby, I also use images and spectra from the Cassini spacecraft, in orbit around Saturn, to study Titan. Titan has long fascinated me for its methane hydrological cycle, in many ways similar to the Earth's but in many other ways completely alien. For years our best tool to study Titan was the Keck telescope, but these days we use Cassini. While buiding bigger telescopes is always better, sometimes it is easier just to fly your telescope to the place you want to study and look from there.
[Image credits: Robert Hurt (IPAC); Barbara Staggs]