1. Our Sun

2. The Sun Largest object in the solar system
The sun has 99% of all mass in the solar system
It is low density—similar to gas giants
The sun controls motions of all objects in the solar system
Planets
Comets
Asteroids

4. Layers of the Sun

5. Layers of the sun Core is the innermost layer
It is more dense than lead, but not solid
It is the site of nuclear fusion
18,000,000 oF!
Photosphere is lowest layer of Sun’s atmosphere
400 km thick
It is the visible layer of the sun
Thought of as the “surface of the sun”
10,000 oF

6. Chromosphere is the middle layer of Sun’s atmosphere
Visible only with filters as a red aura
Corona is the top most layer of Sun’s atmosphere
Visible only during a solar eclipse
1.7 t0 3.5 million oF
Extends several million km above chromosphere

7. Other features of the Sun
Solar wind is gas flowing outward from Sun at high speeds
400 km/s
Charged particles from the wind are trapped in Van Allen belts and can be seen as aurora borealis: “northern lights”
Solar flares are eruptions of radiation
Prominence are large jets of gas (loops)

8. Northern Lights as seen from Earth

10. How Northern Lights Work

11. Sunspots Sunspots are dark spots on Sun’s surface
Sun’s magnetic field breaks through photosphere
Appear darker because of cooler temp.

12. Close up of sunspot

13. Solar Prominences

16. The Sun’s Energy Nuclear fusion of Hydrogen into Helium
Not all of Sun’s energy reaches Earth because of the atmosphere
Our sun is “middle aged” having converted half of its Hydrodgen

17. Visible light
Spectrum is the arrangement of visible light based on wavelength
Violet is the shortest wavelength
Red is the longest wavelength
3 types of light
Absorption
Emission
Continuous