Science
How do stars form?
A star forms when a giant cloud of gas and dust collapses under its own gravity. As it shrinks, the center grows incredibly hot and dense until nuclear fusion ignites — and the star begins to shine.
See it in motion.
Watch a 2-minute animated lesson that shows exactly how stars works.
Step by step
- 1It starts as a vast cloud of gas and dust.
- 2Gravity pulls the cloud inward, making it collapse.
- 3The core heats up as it becomes denser.
- 4When it's hot enough, nuclear fusion ignites and the star shines.
Frequently asked questions
- How do stars form?
- Clouds of gas and dust collapse under gravity until their cores get hot enough to start nuclear fusion.
- What makes a star shine?
- Nuclear fusion in its core converts hydrogen into helium, releasing enormous light and heat.
- How long do stars live?
- From millions to billions of years, depending on their mass — smaller stars last far longer.