Michael Grzeskowirk, age 13, of Staten Island, N. Y., for his question:

What is a chromosphere?

The dazzling face of the sun is veiled in layer upon layer of glowing gases. These filmy gases are the sun's atmosphere, and, like the earth's atmosphere, they get thinner and thinner as they reach above the surface. The upper layer is the corona, which gets thinner and paler as it reaches far, far out into space. The lower layer is the chromosphere.

Our radiant sun is a sphere of burning gases, but its gases are so densely packed that a telescope cannot See deep into its fiery heart. It can probe only through the sun's atmosphere to the photosphere, a term which means sphere of light. The photosphere is much thinner than our air, but the eye of the telescope cannot probe it,; seething gases.

Above the photosphere is the atmosphere of hazy gases. The first level is the chromosphere, which means sphere of color. Its color is brilliant red, and its sphere is a shell more than 8000 miles deep. The chromosphere is an almost  transparent veil of color above the dazzling surface of the sun.

The brilliant light from the photosphere out dazzles the thin gases of the solar atmosphere, and as a rule the chromosphere is invisible. However, it flashes into sight during a total solar eclipse. For a short time the brilliant photosphere is blotted out by the dark disk of the moon. Just before and just after total eclipse, the chromosphere above the sun's surface flashes into view for a brief moment.

This is the moment when astronomers can study the sun's filmy sphere of color. A special spectroscope is used to fingerprint its gases. Each eiulent produces its own color as it burns, and the burning gases of the chromosphere leave their marks on the

Rainbow spectrum of color. The brilliant red comes from hydrogen, and other lines on the spectrum tell us that this lover layer of the sun's atmosphere also contains calcium and helium.    

The chromosphere is upset by stormy sunspots on the surface of the sun, and at such times its gases rage up in towering prominences and streaming solar flares. The effects of these monster flares of flaming gas in the sun's atmosphere may reach the earth. They are Often followed by upsets in the earth's magnetic poles, by blackouts in radio and other communications.

The upper chromosphere becomes thinner and finally merges with the Corona. This layer of thinner than thin gases is a pearly blend of pale yellows and greens. Like the chromosphere, it is seen only when the dazzling face of the sun is blotted out. The upper Corona reaches at least 300,000 miles above the surface of the sun, and recent evidence suggests that it may reach millions of miles out into space.