Our Sun is in a continual state of oscillation. Large patches of the Sun vibrate in and out, back and forth, even as the Sun rotates. One mode of Solar oscillation is depicted graphically above, with blue indicating outward motion, and red indicating inward motion. Although sensitive optical solar observatories can only directly detect surface motions, they give information about vibrations occurring much deeper in the Sun. In helioseismology, these oscillations are being analyzed and are revealing unprecedented information about the density, temperature, motion, and chemical composition of the entire Sun.