Everything in the universe is in motion. The Earth turns on its axis, as does the Sun. This image, taken with radio telescopes, demonstrates that the galaxy NGC 4565 is also rotating.
Different colors represent the varying speeds at which neutral hydrogen in the galaxy is moving. Blue corresponds to blueshifted emission (this part of the galaxy is spinning toward us); red is redshifted emission (this part is moving away).
The image also shows the angle at which the galaxy is observed. The curved ends of the colored band indicate that the galaxy is not exactly edge-on. If it were, the graph would form a straight line.