Almost every ancient culture recognized the Sun as the giver of life and primary power behind events here on Earth. The Sun is the center of our solar system, our local star. It has no permanent features because it is gaseous-mainly incandescent hydrogen. The temperature of the Sun's visible yellow disk-the photosphere-is about 9,900oP (5,500°C).Over the photosphere, there are layers of hotter gas-the chromosphere and corona. The thin gas in the corona is at about a million degrees. By using spectroscopic analysis, scientists know that the Sun, like most stars, is made up mostly of hydrogen. In its core, the hydrogen nuclei are so compressed that they eventually fuse into helium.