The Sun
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INTRODUCTIONKuta-sunset.jpg Sun_STEREO_4dec2006_lrg.jpg
The sun is the center of our solar system and the main provider of life one earth. the sun has been a focal point for a lot of research over the years because it has had a very interesting past and evolution so far and it is sure to have a life altering future.





EVOLUTION By Hannah Bogard
More than 4.5 billion years ago, a light gas cloud containing only a few thousand atoms per cubicsun_life-1.gif centimeter was destined to become the sun. At this stage it did not radiate any light and it remained very fragile until it was disturbed either by impact from the outside or by random condensation of a large number of cloud particles.
Now it enters the GLOBULE stage. Several thousand years later random concentrations of globules formed in the condensing cloud causing it to collapse almost in free fall. later the globule would condense to become the sun. Over the next 400,000 years the globule continued to condense a core developed in the center of the globule becoming a PROTOSTAR. The core emitted radiation which caused the matter to become opaque and stopped the free fall using pressure. The core is then stable and enters life as a protostar or protosun.
The protosun continued to contract until it was hot enough to burn deuterium into helium-3. The contractions caused the central temperature to increase and the radiative temperature to decrease. The radiative core grew and with the ignition of hydrogen the protosun became a star!
The sun continues to age and helium collects in its center, it is on its way to becoming a RED GIANT. After 9 billion years 10% of the suns hydrogen will become helium and nuclear fusion reactions will stop producing energy. The sun will begin to slowly collapse under its own weight and the energy created will cause the shell to burn and swell. Now the surface is far away from the central energy source and it appears to glow red. The center becomes overwhelmed with the heat and explodes. The explosion is absorbed into the outer layers which can no longer produce energy. Eventually carbon build up will prevent core explosion.
Unable to create radiation, the solar core will shrink and all matter will be condense until it is about the size of Earth and will rapidly cool into a WHITE DWARF.
Using up its reserve energy the sun will emit yellow and red light. Now it has become a BLACK DWARF. No further collapse will be possible and the core temperature cools until it’s the same as the interstellar space around it. It might eventually encounter another gas cloud and become a new star.
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THE STRUCTURE OF THE SUN
By Hannah Bogard

There are three major interior zones of the sun. the Core is the innermost part where energy is generated through nuclear reactions, the Radiactive Zone where radiation causes energy to travel outward through 70% of the sun. Then there is the Convection Zone where convection currents circulate the suns energy to the surface.

THE SUNSPOT CYCLE By Hannah Bogard
People have been monitoring sunspots since the time of Galileo. A sunspot is a large dark spot on the sun’s surface marked by magnetic activity, they are visible from Earth without using a telescope. They range greatly in size from a few hundred to many thousands of kilometers across. They last anywhere from a few days to a month and gain their darker color because they are cooler than the gas around them. Astronomers have found it useful to define a standard sunspot number index, a minimum of an 11 year sunspot cycle is currently being observed. Observing the sunspot cycle shows how the magnetic density spots on earths surface changes and moves over multiple years.


SOLAR WINDSaurora-3.jpg By Hannah Bogard
Solar winds are high-speed charged particles that constantly blow off the sun at roughly 400 km /second. these “winds” makes the suns presence known throughout a lot of the solar system. Solar winds contain an equal number of electrons and protons, and a few heavier ions. They escape through coronal holes, particularly in periods of low solar activity. “the speed at which these winds travel would allow them to go from Knoxville to Memphis in less than 2 seconds!” (http://csep10.phys.utk.edu/astr162/lect/ sun/wind.html) this process creates a loss of more than 1 million tons of material per second for the sun. this probably seem like a lot but in retrospect to the size of the sun it is really small. The solar winds effect us too. They have a significant influence on Earth’s ionosphere, our magnetic field, our auroras, and a lot of telecommunication systems.

NUCLEAR FUSION IN THE SUN By Magda Aeschbach
Nuclear fusion in the middle of the sun has an equation of: 4 1H + 2 e --> 4He + 2 neutrinos + 6 photons
(http://www.nineplanets.org/sol.html) The sun gets hot enough to burn hydrogen to make helium. At this stage the final molecules have less energy than they starting molecules. Since the energy is saved, the extra energy is let go and is used by the moving molecules. The nuclear process creates high energy photons but they do not get far. They are used to heat the gas, while the helium remains in the middle of the sun the Neutrinos, or elementary particles traveling near the speed of light are let go.
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SOLAR FLARES By Magda Aeschbach
A solar Flare is a violent explosion in the sun (or other stars) atmosphere. They are born from Sun Spots and require telescopes to see them. This explosion releases as much energy as 6 x 10^25th joules (http://www.nineplanets.org/sol.html). Solar Flares move protons, electrons and other ions to near the speed of light. A hazard of Solar Flares is that they can create a proton storm, where protons can pass through the human body and create damage to the biochemical structure.

INTERRUPTION OF COMMUNICATION
By Magda Aeschbach
When large solar flares go off they send out a shock wave containing billions of tons of super hot gas and charged particles that is sometimes intercepted by radio waves. This can cause static. This process can also cause communication problems with satellites which are often shut down during these flares. A Mars Odyssey was made impossible when a large flare erupted causing instructions to be lost, and astronauts at an International Space Station were forced to take cover when flares reeked havoc in the area they were studying. (
http://www.extremetech.com/article2/0,2845,2072861,00.asp)

BIBLIOGRAPHY
The Sun
Solar Winds Image
Solar Flares
Evolution of the Sun
Sun Spot Cycle