What Is The Sun?

    Published: 06-16-2009
    Views: 10,641
    Science expert Emerald Robinson explains all about Earth’s closest star, the Sun.

    Emerald Robinson: Hi I'm Emerald Robinson, in this What Is video we'll take a look at the star of our solar system, the Sun.

    The Sun is a medium-sized star at the center of our solar system and one of the hundreds of billions of stars in the Milky Way galaxy. It's estimated to be about 4.

    6 billion years old and its energy drives Earth's climate and weather.

    The Sun also supports almost all life on Earth through photosynthesis, a process that plants and other organisms use to convert light energy captured from the Sun into chemical energy.

    The Sun is a near perfect sphere of scorching hot hydrogen and helium. It's so big you can fit one million Earths inside it. Its surface temperature is about 10,000 degrees Fahrenheit and it's more than 27 million degrees at its core.

    The Sun gets its energy from nuclear fusion reactions of hydrogen being converted to helium deep in its core. Particles of light called photons carry this energy from Sun's radiative zone to the top level of Sun's interior, the convection zone. There are boiling motions of gases finally transfers this energy to the surface, called the photosphere.

    The Sun also has an atmosphere which can only be seen by the naked eye during a solar eclipse. The Sun's atmosphere is where streams of charged particles called the solar wind are ejected into the solar system. As the solar wind reaches Earth it is responsible for the northern and southern lights in our atmosphere.

    However during intense activities on the Sun's surface a solar flare can inject enough charge particles to disrupt power and communications on Earth. Scientists believe the Sun has enough nuclear fuel for another five billion years. After that the Sun will begin to burn helium and expand a 100 times its current size swallowing the Earth.

    It's believed the red giant Sun will burn for another billion years and then collapse into a white dwarf about the size of planet Earth. Until then, the forecast looks bright for our life-giving star, the Sun.