Stars are formed in big clouds of gas and dust that are found in space. These clouds are called nebulae. Gravity causes these clouds to collapse under their own weight, and as they do, they heat up and start to glow. This is how stars are born.

Once a star is born, it spends most of its life burning hydrogen gas in its core and releasing energy in the form of light and heat. This process is called nuclear fusion. The energy released by nuclear fusion helps to balance the inward pull of gravity. This balance will last until the star eventually runs out of hydrogen fuel.

When a star runs out of fuel, it will begin to cool down and collapse in on itself. If the star is small, it will become a white dwarf - a tiny, hot ball of gas that will glow for billions of years. If the star is very large, it will explode in a supernova and then either collapse into a neutron star or a black hole.