The Sun is the most prominent feature in our solar system. It is the largestobject and contains approximately 98% of the total solar system mass. One hundredand nine Earths would be required to fit across the Sun’s disk, and its interior couldhold over 1.3 million Earths. The Sun’s outer visible layer is called the photosphereand has a temperature of 6,000°C (11,000°F). This layer has a mottled appearance dueto the turbulent eruptions of energy at the surface.Solar energyis created deep within the core of the Sun. It is here that thetemperature (15,000,000° C; 27,000,000° F) and pressure (340 billion times Earth’s air pressure at sea level) is so intense that nuclear reactions take place. This reactioncauses four protons or hydrogen nuclei to fuse together to form one alpha particle or helium nucleus. The alpha particle is about .7 percent less massive than the four protons. The difference in mass is expelled as energy and is carried to the surface of the Sun, through a process known asconvection, where it is released as light and heat.Energy generated in the Sun’s core takes a million years to reach its surface. Everysecond 700 million tons of hydrogen are converted into heliumashes. In the process 5million tons of pure energy is released; therefore, as time goes on the Sun is becominglighter.