Our source of heat and energy
Layers of the Sun
The first layer, working our way outward, is the core. The radioactive zone, the the convective zone, then there is the visible surface known as the photosphere,
the chromosphere, and finally the outermost layer, the corona.
The core is the source of all the Sun's energy. Fortunately for life on earth, the Sun's energy output is just about constant so we do not see much change in its brightness or the heat it gives off. The Sun's core has a very high temperature, more than 15 million degrees Kelvin, and the material in the core is very tightly packed or dense. It is a combination of these two properties that creates an environment just right for nuclear reactions to occur.
In the core of a star the intense heat destroys the internal structure of an atom and consequently all atoms are broken down into their constituent parts. An atom is constructed of protons, electrons and neutrons. Neutrons have no electric charge and therefore do not interact much with the surrounding medium. As a result neutrons leave the core fairly quickly. The protons, which have positive electric charge, and the electrons, which have negative electric charge, remain in the core and drive the reactions which fuel the Sun. The charge neutral material of protons and electrons that makes up the core is called plasma.
The high temperature provides the protons and electrons with a large amount of thermal energy and as a result they move around quite quickly. This motion, combined with the high density of the plasma, causes the particles to continuously slam into one another creating nuclear reactions. It is the fusion, or slamming together, of particular combinations of particles that provides the energy source of the Sun.
The Convection Zone
The convection zone is the outer-most layer of the solar interior. It extends from a depth of about 200,000 km right up to the visible surface. At the base of the convection zone the temperature is about 2,000,000° C. This is "cool" enough for the heavier ions (such as carbon, nitrogen, oxygen, calcium, and iron) to hold onto some of their electrons. This makes the material more opaque so that it is harder for radiation to get through. This traps heat that ultimately makes the fluid unstable and it starts to "boil" or convect.
Convection occurs when the temperature gradient (the rate at which the temperature falls with height or radius) gets larger than the adiabatic gradient (the rate at which the temperature would fall if a volume of material were moved higher without adding heat). Where this occurs a volume of material moved upward will be warmer than its surroundings and will continue to rise further. These convective motions carry heat quite rapidly to the surface. The fluid expands and cools as it rises. At the visible surface the temperature has dropped to 5,700 K and the density is only 0.0000002 gm/cm³ (about 1/10,000th the density of air at sea level). The convective motions themselves are visible at the surface as granules and supergranules.
A solar flare is a magnetic storm on the Sun which appears to be a very bright spot and a gaseous surface eruption. Solar flares release huge amounts of high-energy particles and gases and are tremendously hot (from 3.6 million to 24 million °F). They are ejected thousands of miles from the surface of the Sun.
Solar flares were first observed by in 1859 by Lord Richard C. Carrington. He wrote that as he was watching the sun with a telescope, he saw "two patches of intensely bright and white light" near a huge group of sunspots. Just a few seconds later, the flare has disappeared.
It has been recently discovered that solar flares can cause sunquakes. Sunquakes are violent seismic events on the Sun. When a sunquake occurs, energy is released in seismic waves on the relatively fluid surface of the Sun. These waves radiate in concentric circles from the epicenter of the sunquake. These seismic waves seem to be compression waves (perhaps like "P" waves generated by earthquakes). Sunquakes would rate about 11.3 on the Richter scale. These huge quakes release about 40,000 times more energy than the 1906 San Francisco earthquake.
he Aurora is an incredible light show caused by collisions between electrically charged particles released from the sun that enter the earth's atmosphere and collide with gases such as oxygen and nitrogen. The lights are seen around the magnetic poles of the northern and southern hemispheres.