Astronomy Portal to the Heavens, Deep Sky and Universe

Our Sun

The sun is a ball of gas, made up of hydrogen and helium. A nuclear reactor continually fusing hydrogen into helium the sun has temperature's of millions of degrees. Every second this conversion of the sun's matter  produces four million tons of energy. This energy is necessary for the earth to continue to sustain life on it. Even though the sun is gaseous it has a density 11/2 that of water. The sun's diameter is 860,000 miles making it 110 times larger than earth. It rotates on its axis about once a month.

Our sun is just one of the stars we see in our sky. We are simple much closer to it then any of the other stars we see. The distance from earth is 186000 miles while the nearest star is 4.5 light years out. In comparison to other stars the sun is just about average in size.

The surface of the sun is called the photosphere. Dark spots or sunspots are often observed on the photosphere. Sunspots are not permanent but come and go like storms. They appear black with a bright rim around them. These bright areas areas are the faculae which often remain for awhile after the dark portion disappears. Strong magnetic fields surround sunspots but scientist have much to learn about them. The spots have times when there more prevalent and runs in eleven year cycles.

There is a layer, the chromosphere, that extend up and beyond the photosphere about 3000 miles. Extending far beyond the chromosphere is even another layer the corona. These layers can only be seen during a total solar eclipse, when the moon completely falls in front of the sun.

Earth is one of nine planets that is in orbit around our star. Planet Earth is our place in the universe and everything in the sky appears to travel around it. This is only our perception though as we look out into space. Our sun is the center of our solar system. This system includes all of the objects that are held by the suns gravitational pull. This includes the planets, asteroids, comets and each of the planets satellites (moons).

We experience daylight when our side of the planet is facing toward the sun. The other side of earth is then experiencing nighttime. At nighttime we are able see the stars that were there all along. We can observe them now without the overpowering light from our sun. The brighter objects in our universe become visible to us.

We cannot observe the sun directly with the naked eye or with an optical instrument. Optical instruments can only be used with special filters or by projecting the suns image onto a piece of paper.

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