Facts About the Chromosphere of the Sun

Viewing

• The chromosphere gives off a light called a hydrogen alpha emission, giving it the red color. The light it projects is faint compared to the bright light given off by the photosphere. The general public can only see the chromosphere during a solar eclipse. Scientists are able to observe the chromosphere using special equipment. They filter out all other wavelengths given off by the sun to observe the chromosphere wavelengths of light.

Properties

• The chromosphere is a thin layer, about 2,000 to 3,000 km thick. Its temperature is 6,000 to 50,000 degrees C, increasing with altitude. Scientists speculate that the temperature increases with altitude due to magnetohydrodyamic waves. They believe that the magnetic field lines in the chromosphere become displaced and oscillate when it returns to its original shape. This oscillation creates a wave of energy that increases the temperature of the chromosphere with altitude.

Supergranules

• Supergranules are large bright and dark areas in the chromosphere. They are much larger than the granules observed in the photosphere. The magnetic field of the sun clusters in the supergranules. This makes a web of magnetic field lines on the sun. When the magnetic field lines cross and bunch, the temperature decreases in that area, creating a darker spot on the chromosphere.

Filaments

• Filaments are long, thin jets of gas in the chromosphere that are extremely dense. They appear darker than the areas around them because they do not emit as much red light. They are held in place by the magnetic field of the sun. They are cooler than the areas directly around them, so they appear darker. Filaments are called prominences when they are observed on the edge of the sun.

Spicules

• Spicules are spikes of plasma that appear in the chromosphere. They are about 300 miles in diameter and can rise to over 7,000 km high. Spicules give the chromosphere a jagged appearance. They are extremely short-lived and quick. The jets only exist for about 10 minutes and travel at 30 km/sec. More than 100,000 spicules can be observed at any given time.