What happens exactly at the core of the sun?

 

An illustration of the structure of the Sun. Credit: https://en.wikipedia.org/

The core of the sun is the innermost region of the star, where the majority of its energy is produced. It is located at the center of the sun and extends outward to about 25% of the sun's radius. The core is the hottest and densest part of the sun, with temperatures reaching as high as 27 million degrees Fahrenheit (15 million degrees Celsius) and densities reaching more than 150 times that of water.

At the core of the sun, the extreme temperature and pressure cause hydrogen atoms to fuse together and form helium, a process known as nuclear fusion. This fusion releases a tremendous amount of energy in the form of light and heat, which is then radiated outwards from the sun's surface. The energy produced in the core is what powers the sun and makes it shine.

The process of nuclear fusion in the core of the sun is what keeps the star stable and in a state of equilibrium. The energy produced by the fusion reactions is balanced by the gravitational force trying to pull the sun's matter inward. This balance allows the sun to maintain its size and shape and prevents it from collapsing in on itself.

The sun is a main-sequence star, which means that it is currently in the stable part of its life cycle, converting hydrogen into helium through nuclear fusion in its core. Main-sequence stars like the sun are expected to remain in this stable phase for a significant portion of their lifetime, typically several billion years.