Solar structure. Cutaway artwork of the Sun illustrating its structure. At the sun's core (white) hydrogen atoms undergo nuclear fusion, producing helium atoms and releasing heat and light energy as photons. These radiate outwards through the inner region (radiative zone, yellow) to the outer layer (red, convection zone). Here, solar plasma rises in thermal columns to the visible surface (photosphere). Intense magnetic fields on the surface of the sun inhibit convection, causing some areas to have lower temperatures than others (sunspots, dark spots). These also cause solar prominences (red and white loops), where charged gas is drawn across areas of opposite polarity. The Earth is at lower left, and its magnetosphere is purple.