Why Does the Sun Appear to Have a Surface Despite Being a Ball of Gas?

💡 The Answer

• The photosphere is the visible 'surface' where gas becomes opaque to visible light.
• Below the photosphere, density and temperature rapidly increase, making gas transparent.
• The photosphere's thickness is only about 500 kilometers, giving a sharp edge.
• Granulation patterns on the photosphere are caused by convective cells of hot gas.
• This apparent surface allows us to measure sunspots, flares, and other solar features.