Gravity and Rotation
Part of Hall of the Universe.
The Museum’s Gilder Center is an early voting site. Find your poll site at vote.nyc.
Part of Hall of the Universe.
AMNH/D. Finnin
The shape of a galaxy is a result of the individual orbits and their collective rotation. The force of gravity from all the stars, gas, dust, and dark matter holds a galaxy together.
The flattened disk of a spiral galaxy is evidence of the rapid revolution of stars, gas, and dust around the center. The orbits are nearly circular and share a common plane.
If, however, the orbits are tipped at all angles to one another, the galaxy has a round and puffy shape. Such an elliptical galaxy rotates very slowly.