The Sun
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Transcript of The Sun
![Page 1: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/1.jpg)
The Sun
![Page 2: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/2.jpg)
Properties
• M = 2 X 1030 kg
= 300,000 MEarth
• R = 700,000 km
> 100 REarth
• 70% H, 28% He• T = 5800 K surface,
15,000,000 K core
![Page 3: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/3.jpg)
Structure
![Page 4: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/4.jpg)
Sun’s Atmosphere
![Page 5: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/5.jpg)
Sun’s Atmosphere
• Solar Wind – stream of particles blown out from the sun
• Corona– Extends several million km above surface– T = 1,000,000 K– Emits X-Rays
• Chromosphere– T = 10,000 K– Emits UV
• Photosphere– T = 5,800 K– Emits visible light
![Page 6: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/6.jpg)
Sun’s Interior
• Convection Zone– Energy travels up
toward the surface via rising hot gas
• Radiation Zone– Photons travel through
plasma 1/3 down from surface
• Core– Energy is produced
![Page 7: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/7.jpg)
Sun’s Interior
• Convection Zone– Energy travels up
toward the surface via rising hot gas
• Radiation Zone– Photons travel through
plasma 1/3 down from surface
• Core– Energy is produced
![Page 8: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/8.jpg)
Energy
• Measured in joules or calories
• Power is the rate energy is used
• 1 Watt = 1 joule/s
• We call the power output of a star it Luminosity
• LSun = 3.8 X 1026 watts
![Page 9: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/9.jpg)
Hydrostatic Equilibrium
• Why doesn’t gravity just make the whole star collapse?– Gravity pulls in– Pressure from inside
the sun pushes out– These two things
balance perfectly
![Page 10: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/10.jpg)
How does the Sun shine?
![Page 11: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/11.jpg)
Historical Views
• Burning ball of coal or wood
• Energy release due to gravitational contraction– Kelvin-Helmholtz contraction
![Page 12: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/12.jpg)
![Page 13: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/13.jpg)
Nuclear fusion
• E=mc2
• Cloud of gas collapsed, releasing potential energy
• Gas heats• Gravity creates high
pressure• High pressure and
temperature allow nuclear fusion
![Page 14: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/14.jpg)
![Page 15: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/15.jpg)
![Page 16: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/16.jpg)
• Need high temperature so particles move fast enough to collide
• Nuclear strong force keeps particles stuck together
![Page 17: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/17.jpg)
Proton-Proton Chain
![Page 18: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/18.jpg)
![Page 19: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/19.jpg)
Solar Neutrinos
![Page 20: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/20.jpg)
Solar Thermostat
![Page 21: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/21.jpg)
Random Walk
• Radiation has to make it out of the sun
• Photon bounces randomly off of electrons– Density of Sun’s core
means lots of bounces
• Photons take a few hundred thousand years to get out
![Page 22: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/22.jpg)
Solar Activity
![Page 23: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/23.jpg)
Magnetic Fields
• Material can travel along magnetic field lines
• It is difficult to travel across field lines
![Page 24: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/24.jpg)
Sunspots
![Page 25: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/25.jpg)
Solar Prominence
![Page 26: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/26.jpg)
Solar Prominence Video
![Page 27: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/27.jpg)
Solar Flare
• Sometimes magnetic fields get too stretched and can’t handle the stress anymore
• They break, releasing trapped material
• Video
![Page 28: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/28.jpg)
Coronal Mass Ejections
![Page 29: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/29.jpg)
CME Video
![Page 30: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/30.jpg)
Sunspot Cycle
• Cycle lasts ~11 years– 7-15 yrs
![Page 31: The Sun](https://reader035.fdocuments.net/reader035/viewer/2022070402/5681378f550346895d9f2e5d/html5/thumbnails/31.jpg)
Sunspot Cycle