The Sun - Our nearest star is spinning on its axis as it moves through space. It is moving on an established course rather than wandering and scientists have calculated where in the galaxy it is moving toward. The movement of the Sun is toward a point in the constellation Hercules. It is travelling away from a point in the constellation Columba. The Sun is located on one of the spiral arms of the Milky Way galaxy and in its position within the Milky Way it is the center of our solar system.
The size of the Sun is almost beyond our comprehension. One hundred nine Earths could fit across the diameter of the Sun and it would take a million Earths to fill the interior of the Sun. Its diameter is 1.4 million km (868,000 mi.). Many people wonder why the Sun does not look larger in the sky. The answer is a simple one. The Sun is 150 million km (93 million mi.)away from Earth. The moon looks as large as the Sun from our point of view but that is because it is 400 times closer than the Sun. It is only 3,475 km (2,159 mi.), which is less than the width of the United States.
Stars are given different size and heat classifications. Giants and Supergiants are much larger and hotter than the Sun. White dwarfs and neutron stars are much smaller and colder than our Sun. The Sun is classified in the middle range as a yellow dwarf.
The surface of the Sun is a hot ball of plasma that is neither liquid, gas, nor solid. The outer surface that we see is called the photosphere. It has a temperature of 6000 degrees Celsius (10,800 F).If you look at a photograph of the Sun you will notice that it look pocked. These pock marks are referred to as granules. A granule may be several hundred kilometers wide and will "bubble" for several minutes at a time. Scientists believe that these bubbling granules are really the hot plasma of the Sun's interior coming to the surface.
The core of the Sun is a searing 15 million degrees Celsius on average and contains immense amounts of pressure that are equal to about 100 billion times the air pressure on earth. Because of the buildup of all this pressure atoms come so close to each other that they fuse.
Every second the Sun spends 700 billion tons of Hydrogen protons in this way. And only a small 0.7 percent is turned into light. Each square centimeter of the solar surface emits as much light as a 6000 Watt lamp. Out of this light the Earth's atmosphere absorbs more than half of the Sun's light, 30% of it is reflected into space, 17% is absorbed by the atmosphere, 22% is scattered to the surface by the clouds, and only 31% arrives at the Earth's surface unaffected.
|Object||Diameter||Length of Day||Length of year||Surface Gravity||Distance from Sun|
|23 hrs, 56 min.||365.25 days||1.00*||91-95 million mi.
(147-152 million km)
©Copyright 1998 Elizabeth
Beckett, Holly Bernitt, and Vishwa Chandra.