Look up on a clear night, far from streetlights. You can see a few thousand stars.

Stars are so far away. They look like pinpoints of light, except for the Sun. In the day, sunlight hides the stars.

Stars twinkle because we see their light through Earth's air. On the Moon, there is no air. Stars do not twinkle at all there. Planets twinkle less than stars do.

A star is a giant ball of gas. The Sun is the closest star to Earth. It is medium-sized. There are bigger and smaller stars than the Sun.

Stars have many colors. Some are red, orange, yellow, white or blue. Sirius is the brightest star in the night sky.

People long ago grouped stars into patterns. They are called constellations. Today there are 88 official constellations.

Stars are in huge groups called galaxies. The Sun belongs to a galaxy called the Milky Way. As of November 2026, it holds over 100 billion stars.

Words to know

• constellations: star patterns
• galaxies: huge star groups
• pinpoints: tiny dots
• twinkle: blink with light