1. History of Beliefs Geocentricity Theory Heliocentric Theory
Greek Ptolemy’s theory
The idea that the sun revolves around the earth
Supported by the Church
Heliocentric Theory
Earth revolves around the sun
Considered by the Christian Church as heresy until Copernicus (1543) and Galilei (1632)

2. The Sun The Center of Our Solar System
The Sun – Our Star Attraction
(18 minutes)
Quiz at the end

3. Facts about the Sun Age Distance from Earth Mass Volume Rotation Rate
4.6 billion years old (half way through its life)
Distance from Earth
149,597,900 km
Mass
332,900 times Earth’s mass
Volume
1.3 million times the Earth’s volume
Rotation Rate
25.38 Earth days (equator)
Diameter
109 time Earth’s diameter
1,391,000 km

4. Characteristics of the Sun
The sun is about 72% hydrogen, 22% helium and 1% of other elements
At the core: Nuclear fusion
Every second, 600 million tons of hydrogen fuse to form 596 million tons of helium.
The remaining 4 million tons of hydrogen is converted into energy that makes the Sun shine
It takes a million years for this energy to reach the Sun’s surface. Much of the energy is converted from harmful gamma and x-rays in the form of visible light.
This light energy takes 8 minutes to reach the Earth

5. Anatomy of the Sun Core Radiative Zone Convection Zone Photosphere
Sunspot
Solar Prominence
Chromosphere
Corona

6. Core
The Sun’s nuclear furnace, where fusion reactions initially combine hydrogen atoms to produce helium yielding energy in the process
Temperatures reach 15 million oC and pressure is enormous
Radiative Zone (moving gases)
Energy moves through a surrounding envelope of gas
Convection Zone
Big bubbles of hot gas transport energy to the surface
Photosphere
The Sun’s visible surface. Due to its high temperature, it glows yellow.
It is made up of churning gases, it is not a solid surface

7. Solar Flare: 5. Sunspot (Active Region)
A magnetic storm on the Sun’s surface that is generally cooler then the photosphere around them
Sunspots always occur in pairs
Sunspots are intense magnetic fields that break the Sun’s surface
These field lines break through one sunspot and reenter into another
These are 1000 to 20,000 km in diameter
These frequently generate solar flares
Solar Flare:
A solar flare is an eruption of hot gases from the inner atmosphere of the Sun’s surface.
It travels very quickly and last for only minutes.
“Fountains of hot gases” that travel outward from the chromosphere through the corona
The charged particles from a solar flare affect us in two main ways: They produce the beautiful auroras (the particles / energy interact with the Earth’s poles), and they cause problems in communication systems.
Note: The number of sunspots and solar flares peaks every 11 years when the magnetic field of Sun flips over.

9. Solar Prominence
A solar prominence is a burst of a huge sheet of gases, also from the inner atmosphere. It is much larger than a flare and may last for days or even weeks.
The huge sheet of gases lines itself up along the magnetic field created between the pairs of sunspots
They can go as far as 50,000 km or more above the Sun’s surface
Chromosphere
The inner atmosphere
Corona
The Sun’s outer atmosphere where gas temperatures reach over 1 million oC

10. Sun’s Rotation The Sun rotates on an axis
The Sun’s interior rotates at a different rate then than outer surface
The interior (the core and radiative zone) are believed to rotate as a solid
The outer parts (the convective zone and out) are believed to rotate at different rates that vary with latitude
The result: The outer surface does not rotate at the same rate. As latitude increases, the rate of rotation slows down.
At the equator (middle) – rotation rate is 28 (25) days
At the poles – rotation rate is 37 (36) days
Sunspots are a great way to see the movement

11. Activity 1 and 2
Complete each of the following activities on the Solar graph paper provided.
Answer questions in complete sentences at the bottom of the solar graph paper (3).

12. Activity 1: Plotting Sunspots
Plotting Sunspots Activity
Using the Solar Graph paper, plot the points given in the table. Each represent a sunspot location
Label each plot with the corresponding number
Question 1:
Where do sunspots appear to be occurring on the Sun? Give the value in degrees.

13. Activity 2: Tracking an Active Region
Tracking a Sunspot
Using the Solar Graph paper, plot the points given in the table.
Label each plot with the corresponding date
Question 2:
What pattern does the movement of AR7220 have? How far does it move each day?
Question 3:
The first day AR7216 was seen it was located at N13E75. After 12 days, where would you expect it be?

14. Activity 3: Historical Data Sunspot Location
Using the data provided, graph the number of sunspots from the 1700’s to Look for patterns – does it match the research?
Hand-in
Properly labeled graph.
Questions answered in full sentences.

15. Sunspots of Our Sun Approximately 11 year cycle Solar maximum
Discovered in 1843 by Samuel Heinrich Schwabe
Solar maximum
peak in number of sunspots
Often high number of solar flares during this time
Solar minimum
low number of sunspots

16. Fate of Our Sun

17. Eventually our Sun will …
Deplete its supply of hydrogen
the core will shrink
temperatures will climb
And it will begin to burn helium which in turn will form heavier elements
Form a red giant as the surface will puff up like a balloon, growing cooler, redder
It will eat up all of the inner planets
Not be able to release enough energy to form new elements and hence, fusion will stop
Shed its outer layers, surrounding itself with a planetary nebula (a colorful gas bubble)
This nebula will dissipate distributing various gases – carbon, oxygen, etc.. - throughout the solar system
Only have a collapsed core = 60 percent of the Sun’s mass (the size of earth)
Be a dead remnant, White dwarf, that will eventually cool and fade from sight

18. Note that not all stars die this way
The fate of a star is dependent on its mass
Average stars end as the Sun will
Larger stars will end in a massive explosion – a supernova
Massive stars (10 times that of the Sun), simply collapse into their inner core forming a black hole

19. Crab Nebula 5 minutes
Videos\The_Formation_and_Destruction_of_Stars.asf