>Metric is taught in schools and is the exclusive unit system for scientific work. Not in astrophysics and cosmology. You almost never hear of meters or grams.

>Metric is taught in schools and is the exclusive unit system for scientific work. Not in astrophysics and cosmology. You almost never hear of meters or grams. We use a hodgepodge of different units depending on what is most convenient and sensible. Working in the solar system? AU. In the galaxy? Light-years or parsecs. And in theoretical work, you often will encounter mass measured in electron-volts, distances measured in solar masses, or temperature measured in square meters, or (more often) everything measured in unitless quantities with no dimensions at all. It really does feel a lot like the traditional medieval measuring systems, messy but once you learn them, useful and comfortable in the mind.