The Sun is a huge, bright ball of hot gas that makes light and heat for us here on Earth. The Sun is powered by nuclear energy. This means it is made up of tiny atoms that are held together very tightly in a big ball. Inside the Sun, these atoms are constantly splitting apart and combining to create energy, which comes out as light and heat. The light and heat we receive from the Sun helps us survive, because it helps plants and animals have enough energy to live. So if you see the Sun outside, remember – it's giving us all the light and heat we need to live!