Comparison of Sun and other stars

A star is a ball of hot, glowing gas that is hot enough and dense enough to trigger nuclear reactions, which fuel the star. In comparing the mass, light production, and size of the Sun to other stars, astronomers find that the Sun is a perfectly ordinary star. It behaves exactly the way they would expect a star of its size to behave. The main difference between the Sun and other stars is that the Sun is much closer to Earth.

The radius of the Sun is about average among stars. The radii of most stars fall between 0.2 and 15 times the Sun’s radius, although some giant stars are hundreds of times larger than the Sun. Larger stars usually have larger absolute luminosities.

We receive much more energy from the Sun than from other stars, because the Sun is so nearby. The Sun’s proximity also allows scientists to study its face in detail. A modest telescope can resolve solar structures that are 700 km (400 mi) across—about the distance from Boston, Massachusetts, to Washington, D.C. That level of detail is comparable to seeing the features on a coin from 1 km (0.6 mi) away. Other stars are so distant that the details on their surfaces remain unresolved with even the largest telescopes.