The Sun's energy is supplied by a. nuclear fusion. b. gravitational collapse. c. energy balance. d. neutrinos.

The Sun generates its energy through a process known as nuclear fusion. In the core of the Sun, intense pressure and high temperatures cause hydrogen atoms to collide with each other at very high speeds. When these hydrogen atoms combine, they form a new helium atom. This process releases a tremendous amount of energy in the form of light and heat. The Sun's core is like a gigantic natural nuclear reactor where fusion happens regularly. Every second, about 600 million tons of hydrogen are converted into helium. The energy produced by this nuclear fusion makes its way out from the Sun's core and eventually reaches Earth, providing the light and heat that sustain life on our planet.

Understanding the fundamental concepts of astronomy is crucial to grasp how stars like the Sun work. Stars are massive spheres of hot gas primarily made up of hydrogen and helium. The basic life cycle of a star depends on its mass. Most stars begin their life by burning hydrogen in their core, a phase during which they are called 'main-sequence stars.' The Sun is a typical main-sequence star in this stage. By observing stars at different stages in their life cycle, astronomers can piece together how nuclear fusion drives a star's energy production and helps it shine.

Solar physics is the branch of astrophysics that specializes in the study of our Sun. This field focuses on understanding the many phenomena originating from the Sun's activity. Scientists study solar flares, sunspots, and the solar wind. All these phenomena are directly linked to the energy and processes happening within the Sun's interior. One of the key aspects of solar physics is understanding the flow of energy from the Sun's core to its surface, how it impacts space weather, and ultimately how it influences the Earth. By studying these processes, scientists strive to predict solar events and their potential impacts on our planet.

Stars, including the Sun, are essentially gigantic factories for nuclear reactions. The most common type of nuclear reaction that occurs in stars is nuclear fusion, but other processes can take place as a star evolves. In more massive stars, elements heavier than helium can undergo fusion in their cores. These nuclear reactions are remarkably efficient at producing energy. In the core of the Sun, the fusion of hydrogen into helium proceeds through a series of steps known as the proton-proton chain reaction. This series of reactions turns four hydrogen nuclei into one helium nucleus and releases a vast amount of energy. These reactions are what make stars shine brightly for millions or even billions of years.