16.3 The Sun and Its Layers
By: Joseph Black
Core
The Sun's Core is the central region where nuclear reactions consume hydrogen to form helium. These reactions release the energy that ultimately leaves the surface as visible light. These reactions are highly sensitive to temperature and density.
Radiative Zone
The Sun's raditative zone is the section of the solar interior between the innermost core and the outer convective zone. In the radiative zone, energy generated by nuclear fusion in the core moves outward as electromagnetic radiation. The energy is conveyed into photons.
Convective Zone
The Convective Zone extends from a depth of 200,000 km to the visible surface of the Earth. Energy is transported by convection in this region. The surface of the convection zone is where photons are created. The top layer of this is called the photosphere.
Photosphere
The photosphere is the visible surface of the Sun that we are recognizable with. Since the Sun is a ball of gas, this is not a solid surface but is actually a layer about 100 km thick. Which is small compared to the Sun's radius.
Chromosphere
The chromosphere is a irregular layer above the photosphere where the temperature rises from 6000 to 20000 degrees Celsius. At these temperatures, hydrogen emits light that gives of a reddish color.
Corona
A corona is an aura of plasma that surrounds the sun and other celestial bodies. The sun's corona extends millions on kilometers into space and is most easily seen during a solar eclipse, it can also be observed with a coronagraph.
Sunspots
Sunspots are temporary phenomena on the photosphere of the Sun that appear visibly as dark spots compared to surrounding areas.
Prominence
A prominence is a large, bright, gaseous feature extending outward from the Sun's surface, often in a loop shape.
Flare
A solar flare occurs when magnetic energy that has built up in the solar atmosphere is suddenly released.
Aurora
An aurora is the result of charged particles colliding, creating bright lights in the sky.