The Sun

Ryan Bender
Geology Period-3
10/5/98

Of all the stars in our galaxy we find our Sun the most important. For the sun supports life on earth and keeps the planets in a certain "line".Without the sun we could not survive.

History of the Sun
People have studied the stars since day one. Many cultures have studied and worshiped the sun. This was the earliest form of studying the moon. In 1611Galileo, using the telescope that he invented, discovered dark spots on the moon. Galileo blazed the way for study of the sun. His observations helped to lead the sun being viewed as an evolving body. Soon its properties and variations were understood scientifically. After Galileo the next major discovery of the sun came in 1814. A German physicist by the name of Joseph von Fraunhofer developed the spectroscope. This tool is used to beak down light in to wavelengths. Isac Newton had a mild idea of this in his day, but nothing of this accuracy or detail. The German Scientist paved the road for theoretical explanations of the star. Some of the most recent tools that have been invented to help study the sun are the coronagraph, the spectroheliograph, the magnetograph, and the spectrograph. These tools have enabled us to better understand the magnetic field of the sun and individual characteristics of the sun. Pictured above is Galileo

Composition of the Sun
The radiation that Earth receives from the sun is quite remarkable. The radiation that we receive varies less than 1% over a period of twenty four hours. However this less than one billionth of the radiation given off by the sun. This energy comes from deep with in the sun. The composition of the sun consists of 71percent hydrogen, 27 percent helium, and 2 percent of other heavier elements. This makes the sun, like others, very volatile
At the center of the sun we find the density of the sun to be more than 150 times that of water. For this reason the center of the sun sits at a scorching 29 million degrees Fahrenheit. At this heat hydrogen atoms are under going nuclear fusion. Nuclear Fusion forces two hydrogen molecules to bond together to make one helium nucleus. The energy that is released is called gamma radiation.

Sun Spots
The magnetic field of the suns sunspots were discovered in 1908 by an astronomer from America by the name of George E. Hale. A common sunspot on the sun has a magnetic field strength of 2500 gauss. To put this in relation the earth\'s magnetic field can be measured at less than 1 gauss. These sunspots we tend to find in pairs throughout the sun. In these paired sunspots we find the magnetic fields opposite directions, one into the sun and one away from the sun. There is a changing cycle of the amount of sunspots that can be observed every 11 years on the sun.
The phenomena of the sun spot is understood very well. One other thing we do know about these spots are that they last, on average, no more than a few months. This is a branch of astronomy that leaves much to be uncovered.

Evolution of the Sun
The Sun has been burning for more than4.4 billion years. During this period of time the sun grew to its present size.(It is important to remember this is virtually all speculation.)
Since the sun burns mostly of hydrogen, it is believed that the sun will be able to burn for roughly 4.4 more billion years. After this is will expand to a red giant and burn for roughly a half a billion years. When it finally burns all of this helium(helium fusion will make it a red giant) it will diminish in size to a white dwarf. Then spend a few billion years cooling.

Facts:
Mass (kg) 1.989e+30
Mass (Earth=1) 332830.0
Equatorial radius (km) 695000.0
Equatorial radius (Earth=1) 108.97
Mean Density (gm/cm^3) 1.41
Rotational period (days) 25-36
Escape velocity (km/sec) 618.02
Luminosity (ergs/sec) 3.827e33
Magnitude (Vo) -26.8
Mean surface temperature 6000.0 C
Age (billion years) 4.5
PRINCIPAL CHEMISTRY
Hydrogen 92.15
Helium 7.8%
Oxygen 0.061%
Carbon 0.03%
Nitrogen 0.0084%