Understanding What a Star Is
A star is a massive ball of hot gas that shines by producing energy. The heat and light come from nuclear reactions deep inside, where hydrogen is converted into helium.
How a Star Begins
Stars are born in giant clouds of gas and dust called nebulae. Over time, gravity pulls the material together. As the cloud becomes denser, it heats up and forms a young, glowing object.
The Birth of a True Star
When the core becomes hot enough, nuclear fusion ignites. This reaction releases enormous amounts of energy, and the object officially becomes a star capable of shining for millions or billions of years.
Why Stars Shine
Fusion produces light, heat, and radiation. The outward pressure from fusion balances the inward pull of gravity, keeping the star stable and bright throughout most of its life.
The Simple Takeaway
A star forms when gravity compresses gas until nuclear fusion starts. This process creates the light and energy that make stars the building blocks of galaxies.