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How do stars form?
Quick answer
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. It starts as a vast cloud of gas and dust.
Step by step
- It starts as a vast cloud of gas and dust.
- Gravity pulls the cloud inward, making it collapse.
- The core heats up as it becomes denser.
- When it's hot enough, nuclear fusion ignites and the star shines.
People also ask
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.
Part of the guide: Space & Astronomy →