The Sun's core is about 15 million degrees Celsius, hot enough to fuse hydrogen into helium
Deep inside the Sun, hydrogen is crushed and heated until it fuses into helium, releasing the energy that lights our sky.
The Sun looks serene from 150 million kilometres away, but its heart is a furnace. In the core the temperature reaches roughly 15 million degrees Celsius (about 27 million degrees Fahrenheit), and the matter there is squeezed to around 150 grams per cubic centimetre, several times denser than gold.
Under those conditions hydrogen nuclei slam together hard enough to overcome their mutual repulsion and fuse into helium. Each fusion converts a sliver of mass into energy, and the Sun does this on a staggering scale, turning millions of tonnes of hydrogen into helium every second.
The light and warmth that reach Earth are simply the long-delayed receipts of reactions happening in that unimaginably hot, dense core.
That outpouring of energy creates the outward pressure that holds the star up against its own gravity, a balance that has kept the Sun shining steadily for billions of years.
Sources & references
2 referencesWell-established. Corroborated by 2 independent sources.
