Sun

The sun is a star of about medium size located 93,000,000mi ( 150,000,000km) from Earth. Temperatures reach about 10,000 degrees F on the stars surface and 27,000,000 degrees F at its core. The sun makes energy from nuclear explosions in it's core, using over 4,000,000 tons of hydrogen each second. This star will probably continue burning for five billion more years. Eruptions from the surface can sometimes reach out 500,000 miles (800,000km) into space. The sun is smaller than many stars, but more than 1,000,000 times the size of the Earth.

The sun has strong gravity. If you could stand on its surface, you would weigh 28 times your Earth weight. This gravity holds all the planets in our solar system in orbit, so they do not fly off into space. The sun rotates on its axis and revolves around our galaxy. One revolution takes about 225,000,000 years. All the planets orbit in the same direction. Proxima centauri is the closest star to the sun it is 25,200 billion miles away. The entire solar system is about 7.5 million miles across.

Magnitude is the measure of observable brightness of a star or other heavenly body. The stars that one sees on a clear night appear yo be closer then they really are. Light from the sun takes about 8.3 minutes to reach us. Light from the next closest star Proxima Centauri takes about 4.3 years to rach us. Proxima Centauri is not visible without the aid of a telescope. All the stars in the sky do not look alike. The most visible difference is in the brightness. The magnitude of a star is determined by the size, distance from the Earth, and its temperature.

Stars like the sun are balls of hot gases. The color of a star helps to determine its temperature. Red stars are the coldest stars, with a surface temperature of 3,000 degrees C. The hottest stars can be seen as blue stars. Their temperature is over 20,000 degrees C. White stars are over 10,000 degrees C. Our sun is a yellow star witha surface temperature of 5,500 degrees C.

A star is formed from a swirling nebula, or cloud of dust and gas in space. The forces of gravity press the matter in the nebula together. When the matter is pressed tightly enough, it gets hotter and hotter, until a new star is born. This new star is cool and large although cool is 3,000 degrees C. The new star has a red glow. If the star continues to compress the matter may become one of several different colors. It may become blue, white, yellow or red. In terms of star heat this is hot, warm, lukewarm, or cool. Our sun is like a red star but cooler than a white star.

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