1. Gravity: Stars are massive balls of gas, primarily hydrogen and helium. Their immense gravity pulls the gas inwards, creating incredible pressure and heat in the star's core.
2. Fusion: Under these extreme conditions, hydrogen atoms collide with such force that they overcome their natural repulsion and fuse together to form helium atoms. This process releases a tremendous amount of energy in the form of light and heat.
3. Energy Release: The fusion reaction converts a tiny bit of mass into a huge amount of energy, following Einstein's famous equation E=mc². This energy radiates outwards, powering the star's luminosity and keeping it stable.
In simpler terms:
Imagine you have a tiny ball of hydrogen. If you squeeze it hard enough, the hydrogen atoms will combine to form a helium atom. This tiny change in form releases a huge burst of energy, which we see as light and feel as heat.
Key takeaway: The heat and light of a star is a direct result of nuclear fusion happening in its core, fueled by the immense pressure and gravity.
