All of the energy that we detect as light and heat originates in nuclear reactions deep inside the Sun's high-temperature "core." This core extends about one quarter of the way from the center of Sun to it's surface where the temperature is around 15 million Kelvin (K) (or 27 million degrees Fahrenheit (F)). Above this core, we can think of the Sun's interior as being like two nested spherical shells that surround the core. In the innermost shell, right above the core, energy is carried outwards by radiation. This "radiative zone" extends about three quarters of the way to the surface. The radiation does not travel directly outwards - in this part of the Sun's interior, the plasma density is very high, and the radiation gets bounced around countless numbers of times, following a zig-zag path outward. It takes about 170 thousand years for radiation to make its way from the core to the top of the radiative zone!
SOHO/MDI, SOHO/LASCO (ESA & NASA) SOHO is a project of international cooperation between ESA and NASA. |
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