On a clear night away from streetlights, a person can see a few thousand stars without a telescope. In the daytime, you cannot see them, because daytime sunlight hides the stars from view. Sirius is the brightest star in the night sky. A shooting star is not a star. It is a streak of light from a meteoroid burning up in Earth's atmosphere.

People long ago grouped stars into patterns called constellations. Today there are 88 official constellations. Stars and constellations stay in approximately the same spot in the sky for many years. Which constellations you can see at night depends on the time of year. Polaris stays in the same northerly direction as the Earth turns, while other stars seem to revolve around it. Polaris is not the brightest star in the sky.

Stars twinkle because we see their light through Earth's air. Starlight bends a little each time it enters warmer or cooler air. Seen from the Moon, where there is no air, stars do not twinkle at all. Planets twinkle less than stars do. They tend to glow with a steady light.

Stars come in different sizes, and there are bigger stars and smaller stars than the Sun. Stars also come in different colors, such as red, orange, yellow, white and blue. A star's color tells about its temperature. Blue-white stars are much hotter than the Sun, and red stars are cooler. A red dwarf is too faint to see with the unaided eye.

Except for the Sun, stars are so far away that they look like pinpoints of light. A light-year is the distance that light travels in one year. Proxima Centauri is the nearest star to the Sun. As of November 2026, it is about 4.24 light-years away. The farther away an object in space is, the farther in the past we see it, because light takes time to travel.

Words to know

• constellations: star patterns
• meteoroid: space rock bit
• Polaris: the North Star
• temperature: how hot