1. The Sun?

2. The Sun is a star! There are an incredible amount of stars in the universe. Yay! What is a star…?
A star is a huge sphere of very hot, glowing gas. Stars produce their own light and energy by a process called nuclear fusion. Fusion happens when lighter elements are forced to become heavier elements. When this happens, a tremendous amount of energy is created causing the star to heat up and shine. Stars come in a variety of sizes and colors. Our Sun is an average sized yellowish star. Stars which are smaller than our Sun are reddish and larger stars are blue.
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3. The Sun – Our Star
One of many stars in the Milky Way, but extremely important to us…why?
Energy, understanding other stars

4. Solar Data
The diameter of the Sun is thus 109 times as great as the Earth's diameter.
About 1.3 million Earths could fit inside the sun.
The mass of the sun is x 1030kilograms, about 332,000 times the mass of the Earth.
Volume of the Sun is about 1.5 million times that of Earth’s
Mean density of Sun = 1408 (kg/m3)
Mean density of Earth = 5514 (kg/m3)

5. Solar Parts
A ball of gas, which can be generally thought of as having four “layers”:
Solar interior (core, radiation zone, convection zone)
visible surface (photosphere)
‘visible’ ‘layer’
two atmospheric components
chromosphere
corona

8. Solar Activity
Sunspots: dark regions on the Sun that are slightly cooler than surrounding surface, and are associated with very strong magnetic activity.
Granules: ‘boiling effect’ cause by circulation of energy in the convection zone.
- size of Earth and only last 8-10 minutes
Composition surface = 74% Hydrogen, 25% Helium, 1% other

9. Sunspots
Observed throughout antiquity (try looking at the sun at its lowest point in the sky, or through a cloud bank and you can occasionally see them unaided)
Deduction of Solar Rotation rate and differential rotation nature from sunspot observation
Dark spot? Not really. Many X brighter than Full Moon. Its relative.
Plage = lighter areas around the sunspots

10. Chromosphere Layer above the photosphere Not visible to the naked eye
Hot, low density gas produces an emission spectrum
Appears red due to concentration of hydrogen gases

11. The Corona
Only visible when the solar disc is covered (during a solar eclipse or with a coronagraph)
Very hot, High energy, low density particles escape the gravitational pull of the Sun
Released as streams of ions and radiation outward from the Sun

14. Sunspots

16. Prominences/Flares

17. Prominences/Flares
Flares are massive eruptions from the surface of the Sun resulting in huge amounts of charged particle energy ejected into space (CMEs – Coronal Mass Ejections)
Threating to astronauts, damaging to communication systems
Kill shot? Radio/X-Ray/UV radiation
Prominences are large looping structures of solar material tapped by magnetic fields.

24. Aurora Borealis/Australis Colors

28. Solar Interior

30. Missing Matter -> Energy
Matter is converted to energy according to Einstein's famous formula:
E = mc2
c = speed of light (3x108m/s)
M = mass (kg)
E = energy (Joules [J])
A Joule is a unit of energy equivalent to the energy needed to apply a force of 1 Newton through a distance of one meter.

31. How much energy in matter?

32. The equivalent of energy that would be produced by burning 1000 tons of coal!!

33. Solar Fusion
4 million tons of Hydrogen converted to energy every second in Solar core!
This consumes 600 million tons of Hydrogen “fuel” every second!
How long can such fuel consumption keep up before the Sun run’s out?
At present rate: about another 100 billion years!! Conclusion?

34. Solar Fusion
The Sun can last for a long time, however it will not last for another 100 billion years
In about 4.5 billion years, the Sun will swell into a Red Giant star.
This will happen b/c the Sun has run out of Hydrogen fuel in its core, resulting in less outward pressure and gravitational contraction, leading to increased pressure/temp. and fusion of heavier elements.