Science
What is the Sun?
The Sun is the star at the centre of our solar system — a giant ball of hot, glowing gas (mostly hydrogen and helium) that gives Earth light and heat. Its gravity holds all the planets in orbit, and nuclear fusion in its core powers nearly all life on Earth.
See it, don’t just read it.
Watch a 2-minute lesson with voice + animation that explains the sun.
Key things to understand
- 1The Sun is a star — the closest one to Earth, about 150 million km away.
- 2It's a huge sphere of plasma, mostly hydrogen and helium, around 1.4 million km across (over a million Earths would fit inside).
- 3Its energy comes from nuclear fusion in the core, where hydrogen fuses into helium, releasing enormous light and heat.
- 4Its gravity keeps the planets, including Earth, in orbit around it.
- 5Sunlight drives Earth's climate, weather, and — through photosynthesis — almost all life.
Frequently asked questions
- Is the Sun a star?
- Yes — the Sun is a medium-sized star, the closest one to us. It only looks bigger and brighter than other stars because it's so much nearer.
- What is the Sun made of?
- Mostly hydrogen (about 73%) and helium (about 25%), with traces of heavier elements. It's not solid — it's a giant ball of superheated plasma.
- How does the Sun produce energy?
- By nuclear fusion: in its core, hydrogen nuclei fuse into helium under crushing pressure and heat, releasing the energy that reaches us as sunlight.