solar physics

The Sun rings like an enormous bell. Convection keeps striking it, and the resulting sound waves bounce around inside, shifting the visible surface by tiny amounts. Measuring those shifts lets astronomers map the Sun's interior, rotation, and composition.

Every 11 years or so, the Sun's magnetic activity rises and falls in a cycle that astronomers have tracked since Galileo's era. The solar cycle sets how many sunspots, flares, and coronal mass ejections occur, and it shapes space weather at Earth.

If the Sun stopped shining tomorrow, Earth would still feel its gravity but lose its energy. Here's what would actually happen — minute by minute, day by day, month by month.