| Galaxy and cosmic microwave background (CMB) surveys see the Universe in very different ways, but the measurements they provide are remarkably complementary. I will discuss how data from these surveys can be combined to improve our understanding of the astrophysics of gravitationally bound structures across an enormous range of length scales. Starting with the largest bound structures in the Universe, I will discuss how galaxy and CMB surveys can be used to study the mass and gas profiles of galaxy clusters. The cluster mass profiles provide insight into the "splashback" phenomenon, which is a powerful probe of cluster accretion and quenching of star formation. The gas profiles, on the other hand, are important for understanding baryonic feedback processes, and for extracting cosmological constraints from weak lensing surveys. Moving to scales roughly 10 million times smaller, I will discuss how CMB surveys can be used in conjunction with optical data to study material in orbit around stellar systems. In particular, I will show how CMB surveys may prove useful for detecting a Planet 9 in our own solar system, and for detecting Oort clouds around other stars. |