The Sun Key Terms

nuclear fusion

a nuclear reaction in which atomic nuclei of low atomic number fuse to form a heavier nucleus with the release of energy.

radiation zone

the layer of the sun's interior where energy is transferred mainly by electromagnetic radiation

Convective Zone (Convection Zone)

a region of the sun where gases circulate in convection currents, bringing the sun's energy to the surface

Photosphere -(of the Sun)

the visible surface of the sun


The middle layer of the sun's atmosphere


The outer layer of the sun's atmosphere.


A dark area of gas on the sun's surface that is cooler than surrounding gases.


A loop of gas that protrudes from the sun's surface, linking parts of sunspot regions

solar flare

An eruption of gas from the sun's surface that occurs when the loops in sunspot regions suddenly connect

coronal mass ejection

a part of coronal gas that is thrown into space from the sun


an atmospheric phenomenon consisting of bands of light caused by charged solar particles following the earth's magnetic lines of force