Why Stars Shine: Heat and Nuclear Fusion

Stars shine because nuclear fusion in their cores turns hydrogen into helium.
Fusion releases enormous energy as light and heat, powering the star’s glow.
The Sun fuses about 600 million tons of hydrogen every second.
Extreme pressure and temperature in the core—millions of degrees—make fusion possible.
The light we see took thousands of years to travel from the Sun’s core to its surface.
Fusion balances gravity’s inward pull, preventing stars from collapsing.
Different stars fuse different fuels—massive stars even burn helium, carbon, and heavier elements.
The energy radiates outward as visible light, ultraviolet rays, and infrared heat.
Without fusion, stars would just be cold balls of gas, invisible in the cosmos.
Fusion makes stars the universe’s power plants, forging both light and the elements of life.