Galaxies Don’t Spin The Way You Think

Galaxies Don’t Spin The Way You Think

A galaxy is a gravitationally bound system of stars, stellar remnants, interstellar gas, dust, and dark matter. The word galaxy is derived from the Greek galaxias (γαλαξίας), literally « milky », a reference to the Milky Way. Galaxies range in size from dwarfs with just a few hundred million (10⁸) stars to giants with one hundred trillion (10¹⁴) stars, each orbiting its galaxy’s center of mass.

Galaxies are not spinning tops. So how do stars move within them?