Life on Earth would cease to exist without the Sun. The Sun is the main source of energy for the Earth. It provides energy as light and heat.
Plants convert the solar energy to chemical energy in a process called photosynthesis.
Gravity from the Sun keeps all of the planets in their orbits. This is the only temperature range that can sustain life. It is different from an average star because it larger and burns hotter. Fortunately, the Sun is not any larger because larger stars are much brighter and do not last as long as smaller ones because they burn more fuel on a similar time scale. In the years that followed, Kelvin studied the Sun and calculated that it would burn for about 30 million years.