Layers of the Sun
The Sun consists of six distinct layers, each with unique properties and functions.
The following sections outline these layers:
- Core
- The innermost and hottest layer of the Sun, where nuclear fusion occurs.
- Temperature: Approximately 15 million °C. (gaseous state)
- Density: About 160 g/cm³, significantly denser than lead. (10 times that of lead).
- Fusion reactions in the core produce energy in the form of gamma rays and neutrinos, which eventually move outward to the surface.
- Radiative Zone
- Surrounds the core and extends outward to about 70% of the Sun’s radius.
- Temperature: Around 4 million K.
- Density: Less dense than the core.
- Energy produced in the core moves through this zone primarily by radiation, taking thousands of years to reach the outer layers.
- Convection Zone
- The outer layer of the solar envelope, above the radiative zone.
- Temperature: About 2 million K at the bottom and cooler at the top.
- Energy is transported by convection currents, forming granules on the surface as hot gas rises and cooler gas sinks.
- Photosphere
- The visible surface of the Sun.
- Temperature: Approximately 6,000 °C.
- This thin layer is where most of sunlight is emitted and has a low pressure. It appears granulated due to convection currents.
- Chromosphere
- A thin layer above the photosphere.
- Temperature: Approximately 7,000 K.
- Visible during solar eclipses as a red halo due to the presence of hydrogen. The temperature increases as you move outward from the photosphere.
- Corona
- The outermost layer, extending millions of kilometres into space.
- Temperature: Around 1 million K or more, making it the hottest layer.
- Very faint and difficult to observe; visible during total solar eclipses. The corona is the source of solar wind, which consists of charged particles moving at high speeds.