Click the link for the Sun Quiz.  If you need help, read the notes below.

The sun is a medium sized star which is the center of the sun or solar system. . Its gravitational pull holds the planets, comets, etc. orbiting about it. It is the closest star to the earth at about 93,000.000 miles away. It is about 865,000 miles in diameter.

Why is the sun so important?Sun animation

Without the heat and light of the sun, there would not be life on earth. Solar energy is used by green plants for photosynthesis. . Solar heating is the source of the energy of moving air. Solar energy also effects the process of the water cycle,

The sun is a star of about medium size. The sun appears larger than the other stars because it is the nearest star to the earth. The mean distance is around 93,000,000 miles or 150,000,000 kilometers. This number is also the astronomical unit (A.U.) of distance used for measuring distances within the solar system.

The sun is about 870,000 miles or 1,400,000 kilometers in diameter, and its volume is about 1,300,000 times that of the earth. Its mass is almost 700 times the total mass of all the bodies in the solar system and 332,000 times that of the earth. The sun's gravity is almost 28 times that of the earth. For example, if a person weighed 100 pounds on earth, they would weigh 2800 on the sun.

The sun's surface is called the photosphere. Its temperature is about 6,000 degrees Celsius. During an eclipse of the sun the chromosphere and the corona (the outer layers of the sun's atmosphere) are seen. Sometimes, the corona extends outward into space.  When this occurs it is called the solar wind.

With the spectroscope scientists have learned much about the sun. There are many dark lines of different widths in the solar spectrum. By studying these lines the substances that make up the sun are known. By comparing the sun's spectrum with spectra of known elements, most of the elements known on earth have been identified in the sun's atmosphere.

Astronomy Astronomy Main Page