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II. The Sun As a Source of Radiation

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    Before we become highly involved in the details of how we obtain power from the sun’s rays, it is always necessary to understand the details about why the sun is such an abundant source of energy. In this section we will explain how the sun generates the radiation we receive on the earth.

    The sun seems reliable, stable, and convenient since our Earth is the perfect distance from the sun to maintain our existence. Within the sun, however, is much turmoil; the giant ball of gas is a dense, extremely hot, violent soup of nuclear reactions that is eating up its fuel and coming closer and closer to reaching the end of its life. Don’t worry! This will not happen anytime soon.

    Here are some main facts about the sun:

    • The sun contains hot plasma, which is essentially ionized gas. The movement of plasma and gas in the sun create an enormous, twisted magnetic field that causes some familiar phenomena such as sunspots and the solar cycle.
    • The sun was formed roughly 4.5 billion years ago, and is thus halfway through its main-sequence evolution, meaning that it is still young.
    • It is a relatively small yet bright star in the Milky Way Galaxy (classified as a type G2V star).
    • Once the core of the sun has used up all its fuel, it will shed its outer layers of hot gas as a planetary nebula and cool off into a white dwarf.


    Above we see traces of the sun’s magnetic field, which in some places forms twisted magnetic loops that create many solar phenomena. This warped magnetic field gives us an idea of the amount of activity going on in the sun’s interior.

    Source: <>

    II. The Sun As a Source of Radiation is shared under a not declared license and was authored, remixed, and/or curated by LibreTexts.

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