Sun+2A

Here's the basics about the Sun:
 * Its made of hot gasses: Helium Hydrogen, and about 1% other
 * its 93 million miles away from us
 * its 8000 miles wide and 900,000 miles across
 * Its four billion years old
 * Ten million degrees
 * Its earths primary source of engery
 * The sun is divided into four parts: **solar interior**, the **photosphere**, **chromosphere**, and the **corona**.
 * The sun is one of 100 billion stars that make up the milkly way galaxy.

=**The Suns Layers**=


 * Photoshpere**: radiates most of the sunlight we see and can be thought of as the visible "surface" of the sun. Consists of a layer of gas less than 500 km thick. Granules are narrow, dark regions on the suns photosphere and only survive about 10 to 20 mins. The composition of the photosphere is revealed by the dark lines of its absortion spectrum. (90% of the suns surface atoms are hydrogen, 10% are helium, and only minor ammounts of other elements.)


 * Chromosphere**: A thin layer of hot gases and is a thousand kilometers thick. You can see the chromosphere during a solar eclipse or by using an instrument to block out the light from the photosphere. The chromosphere is thin red rim around the sun and because the chromosphere consists of hot gases it produces an emission spectrum that is the reverse of the absorption spectrum of the photoshere. The bright lines of hydrogen is the amount of its total light and account for the sphere's red color.


 * Corona**: Is the outer portion of the solar atmosphere. The corona is very weak and is only visible when the photosphere is covered.The ionized gases extend a million kilometers from the sun and produce a glow that is almost as bright as the moon. The outer fringe of the corona, the gases have speeds that are good enough to escape the gravity pull of the sun. The protons and electrons that boil from the corona constitute the **solar wind.** The wind goes out towards the solar system at the speed of 800 kilometers per second and then gets lost into space. The energy from the photosphere show that the temperature avareage is about 6000k. Going up from the photosphere the temperature increases. Although the corona temperatue is hotter then the photosphere its much less energy because its density is low.


 * Sunspots:** They are dark circles around the Galileo. Sunspots are dark regions on the surface of the photsphere. A individual spot is a black centered rimmed by a lighter region. Sunspots apper dark because of thier temperature, which is about 1500k less than the surrounding solar surface. The number of sunspots increases to a maxium with a hundred or more at a given time. Then the numbers decline to a minimum when only a few or none are visible.


 * Prominences:** they are huge cloudlike structures consisting of chromospheric gases.they often appear as great arches that extend well into the corona.they are ionized gases trapped by magnetic fields that extend from regions of intense solar activity.

During a solar flares existence, solar flares release enormous amounts of energy, much of it in the form of ultraviolet, radio, and X-ray radiation.
 * Solar Flares:** They are the most explosive events associated with sunspots. They are brief outbusts that normally last about an hour and appear as a sudden brightening of the region above a sunspot cluster.
 * Auroras:** Most spectacular effects of solar flares. Also called the Northern and Southern Lights.

=**The Solar Interior**=

Solar interior cannot be observed directly.
 * Nuclear Fusion:** The energy the sun produces deep in its interior. During nuclear fusion, energy is released because some matter is actually converted to energy.