What are stars? Stars are made up of really hot gas. The gas is mostly made up of hydrogen and helium (helium is what makes balloons float!). Stars burn hydrogen to create helium. This process makes the star really hot and shine really bright and is called nuclear fusion.

Stars are born and they die when they complete their life cycle. The steps of a star’s life cycle are:

Life Cycle of a Star diagram. The basic steps of a star's life.
  1. Birth. Gas (remember the hydrogen and helium?) and dust particles called nebulae are brought together in space by gravity. The gas and nebulae are squished together until the center gets really hot. That’s when nuclear fusion begins!
  2. Main Sequence Star. Once the star is born, it will burn for billions of years. The star will stay in this phase until it runs out of hydrogen to burn. This is the longest part of the star’s life.
  3. Red Giant. The star expands! The star glows brighter, and the temperature of the star decreases.
  4. Collapse. Once all the star’s fuel is all used up, the star will collapse. When a star collapses, it can become a white dwarf star or, if it was really big, it can explode into a supernova!

So what are constellations?

Constellations are groupings of stars that form a pattern in the sky. They can make different patterns, like people, animals, or objects. There are 88 constellations!

The Big Dipper, one of the constellations.

In ancient times, constellations were used to keep track of the calendar and seasons. Stars have also been used by navigators to help them find their way. Have you ever heard of the North Star? The North Star is located almost directly above the North Pole. Explorers could use the North Star to determine which way was north! No need for GPS!

People have been fascinated with stars for centuries, and even today people like to stargaze for fun. Go outside tonight and see what stars you can find!

Download this free printable for the cool stories behind the constellations and their names.

For a fun space activity, make a flashlight constellation viewer! Get the instructions here, and video instructions here.

Stars and Constellations science lesson and STEM activity for kids.