What is the process that powers stars, including the Sun?

The process that powers stars, including the Sun, is nuclear fusion. In nuclear fusion, hydrogen nuclei combine under extreme temperatures and pressures to form helium nuclei, releasing a substantial amount of energy in the process. This energy is what we observe as light and heat emitted by the star.

In the core of the Sun, temperatures reach around 15 million degrees Celsius, providing the necessary conditions for nuclear fusion reactions to occur. The energy produced not only supports the star against gravitational collapse but also drives the ongoing processes within the star that ultimately lead to stellar stability and evolution.

Understanding nuclear fusion is critical when studying stellar lifecycles, as it influences everything from a star’s brightness and color to how long it will spend in each phase of its lifecycle. Consequently, this process is fundamental to both the physics of stars and a variety of phenomena in the universe, including the creation of heavier elements through subsequent fusion processes in more massive stars.