Facts about the Sun's Photosphere

The portion of the sun we see is called the photosphere.
••• Siri Stafford/Lifesize/Getty Images

The surface of the sun, or photosphere, is a yellow-colored layer of thick, hot gases marked with dark spots, known as sunspots. It is the lowest visible layer of the sun.


The photosphere is 5,780 degrees Kelvin (K), which is relatively cool compared to the inside, measured in the millions of degrees, and the atmospheric edge, which is also measured in the millions of degrees.


The gases that make up the photosphere are completely opaque, meaning that you cannot see through them. Therefore, stating that the sun has “surface” is a misnomer, for the photosphere is not solid.


The photosphere is above the solar convection zone, where heat from the core radiates outward and below the chromosphere, where heat is transferred to the outer layer of the sun, called the corona.


The photosphere is constructed of convection cells called granules, which are cells of hot gas 1,000 km in diameter. Each granule lives 8 to 9 minutes, which produces a “boiling” effect.


Sunspots are cooler regions of the photosphere that appear dark because of their lower temperatures of 3,800 degrees K versus 5,780 degrees K. Sunspots can vary in size up to 50,000 km in diameter.

Related Articles

Unique Facts About the Sun
The Outer & Inner Parts of the Sun
Describe the Surface Terrain on Jupiter
Facts About the Chromosphere of the Sun
Why Is the Sun So Bright?
What Is the Average Temperature of Jupiter?
What Is the Surface Terrain Like on Neptune?
5 Facts About the Earth's Inner Core
How Does the Sun Release Energy?
Geology Facts on Neptune
Parts of a Star
Which Planet Is Considered Earth's Twin in Mass & Size?
Three Major Characteristics of the Inner Planets
Characteristics of a Star
The Characteristics of Comets, Meteors & Asteroids
How is the Sun Nuclear Energy?
Facts About the Sun for the Third Grader Level
How to Find Partial Pressures
What Is the Earth's Atmosphere Composition & Temperature?