1. The Sun
One million Earth’s could fit inside of the sun, approximately.

2. The Sun: Sol, Helios, Ra The Sun formed about 5 billion years ago.
One of more than 100 billion stars in our galaxy
The Sun is an average-size, middle-aged star.
It contains more than 99.8% of the total mass of our solar system
The Sun is, at present, about 70% hydrogen and 28% helium by mass everything else (metals) amounts to less than 2%
Sol = Roman god of the sun
Helios = Greek word for sun
Ra = Egyptian god of sun

3. Unlike the Earth, the Sun does not have a solid surface.
The Sun’s Interior
Unlike the Earth, the Sun does not have a solid surface.
It is a glowing ball of densely packed gas.
Like the Earth, it has an atmosphere and an interior.
The Sun’s interior consists of the Core, the Radiation and the Convection Zone

4. The Core
The Core reaches 15 million degrees Celsius. The sun does not burn fuel, rather the energy comes from the nuclear fusion at the core.
0 degrees C = 273 Kelvin; add 273 to your number in degrees C
Fusion is the combining of particles, and the process releases energy. (hydrogen  helium)
The core is made up of hot, dense gas is the plasma state
Skylab SpaceStation 
NASA 10 December 1973

5. The Radiation Zone The energy leaving the Sun is from fusion.
The Radiation Zone is a region of very tightly packed gas where energy is passed.
Energy in the Radiation Zone may take up to 100,000 years to make it to open space.
7 million degrees C at the bottom, decreasing to 2 million at the top.
It takes so long, because although it’s traveling at the speed of light, it bounces so many times through the dense material, it takes that long!!

6. Ultimately, electromagnetic radiation determines Earth’s climate
The Electromagnetic Spectrum
The energy Earth receives from the sun is called electromagnetic radiation. The full range of radiation is called the electromagnetic spectrum, shorter wavelengths have more energy than longer wavelengths.
Ultimately, electromagnetic radiation determines Earth’s climate

7. The Convection Zone
The convection zone is the outer-most layer of the solar interior.
The temperature is relatively cool, now only 2 million degrees Kelvin
This “mixing” process is called convection, hence the name, convection zone!
The hotter material near the top of the radiation zone (the bottom of the convection zone) rises up and the cooler material sinks to the bottom.

8. The Layers of the Sun: Atmosphere
The Sun’s Atmosphere consists of 3 layers
The Photosphere
The Chromosphere
The Corona

9. Photosphere Inner, most dense, layer of the atmosphere.
Photos is Greek for light, hence photosphere means “Sphere of light”.
Gaseous surface, not solid.
Temperature of about degrees C
Temp from bottom to top

10. Chromosphere Middle layer of the Sun’s Atmosphere.
Visible during a Solar eclipse as a reddish zone.
Less dense gas giving off faint light.
From Greek Chroma, meaning “Colored”, hence the Chromosphere is the “Colored sphere”
C from bottom to top
Chromosphere
C from bottom to top, get’s hotter!!

11. Corona
Outer most, and least dense, gaseous layer of the Sun.
Extends millions of kilometers into space but is visible only during a total solar eclipse
Appears as a faint halo around the Chromosphere
Temperatures from 500,000 degrees C, up to a few million!!!
500,000 degrees C up to a few million
Solar eclipse = moon blocks the sun

12. Features on the Sun
Sunspots appear as small dark spots on the surface of the Sun.
Sunspots are much cooler than the rest of the surface and therefore don’t emit as much light.
Sunspots move! The sun must be rotating on an axis!

13. Prominences are reddish loops of gas linking sunspots and are particularly noticeable when occurring on the edge of the sun.

14. Solar Flares
When prominances touch, they short circuit each other, causing a solar flare!
When this happens, energy is being released, and it causes a sudden, bright flash on the surface of the sun.
The energy they emit into the solar system can be dangerous
The energy they emit crosses a wide range of energy types from the spectrum, and can damage equiptment in space, as well as expose us to harmful radiation

15. Solar Wind
Stream of charged particles released from the surface of the sun at very high speeds
The corona is so hot, that the sun’s gravity can’t hold on to it
Helps shape magnetic fields around planets, and is the reason for the tail of a comet
Aurora borealis & aurora austrailis (northern & southern lights, respectively)  electrons colliding with the upper reaches of the Earth’s atmosphere
You can see them at the magnetic poles (Alaska & northern Canada or Norway sweeden or findland)

16. Since its birth, our Sun has used up about half of the hydrogen in its core.
It will continue to radiate "peacefully" for another 5 billion years or so (although its brightness will approximately double in that time).