Stars and Galaxies — PHY2106.01
All but a handful of the objects you see in the night sky are stars in our Galaxy, the Milky Way. Although we know about these stars only from studying their light, we know today that they are not just points of light, but large, gravitationally‐bound balls of plasma governed by the laws of physics. Stars, together with dust, gas, and dark matter, are found in larger structures – galaxies. In turn, galaxies, are located in even larger structures called galaxy groups and galaxy clusters.