Goal: To understand how the sun works

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Goal To understand how the sun works

• Objectives
• Journey to the center of the sun!

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Spaceship Sol

• Scheduled departure time 5 min.
• Please fasten seatbelts.
• What color is
• The sun?
• Yellow
• Orange
• Blue
• White
• Red

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Spaceship Sol

• Scheduled departure time 4 min.
• Prepare for departure.
• Is the sun
• a star?
• Yes
• No

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Liftoff! Travel distance 93 million miles
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(No Transcript)
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• Heliosphere
• Solar Wind
• speed 390.0 km/s
• density
• 7 protons/cm3
• Outside temp
• 292K
• 68 F
• Density outside
• Almost 0.

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• Outside temp
• 400K
• 262 F
• Density outside
• 10 protons/cm3

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• Outside temp
• 450K
• 352 F
• Density outside
• 28 protons/cm3

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• Outside temp
• 604K
• 618 F
• Distance to sun
• 20 million miles
• Density outside
• 140 protons/cm3

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• Outer area of the corona - the start of the solar
  wind
• Outside temp
• 1208K
• 1705 F
• Distance to sun
• 5 million miles
• Density outside
• 2200 protons/cm3

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• Corona millions of degrees!
• Outside temp
• 2415K
• 3879 F
• Distance to sun
• 1.25 million miles
• (0.8 million from the surface)
• Density outside
• 35000 protons/cm3

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• Corona
• Outside temp
• 1 million K!
• 100k miles from the surface

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• Chromosphere
• Outside temp
• 10000K
• 1k miles from the surface
• CORONAL MASS EJECTION!!!

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• Rotation of the sun.
• The sun rotates every 26-28 days, depending on
  where on the sun you are.
• Why could this be important?

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• Photosphere
• Outside temp
• 5800K
• Surface!
• Density
• 1 of air.
• All of the suns light that we see comes from
  here.
• Question
• If we fly in onto that sunspot, will it be dark
  or light?

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• Photosphere
• Outside temp
• 5800K
• Surface (400 km deep)!
• Sunspots are light!
• They are 1-2k
• cooler, so
• compared to
• the rest of the
• sun, they
• appear to be
• darker.
• Granules
• Convection
• cells. Kind of
• like in a pot

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• Welcome to the sun! http//www.nasa.gov/mpg/118091
  main_other_loop_sm.mpg

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http//thesurfaceofthesun.com/tsunami.htm

• SUN QUAKE!!!

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Warning breathing apparatus will be required as
the sun is made of 74 Hydrogen, 25 Helium, and
only 1 other stuff. Question where on
or in the sun is there a solid surface to land on?
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How dense is the sun?

• A) About the density of air
• B) About the density of water
• C) About the density of lead
• D) more dense than any material on earth

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How dense is the sun?

• B) About the density of water
• The average density of the sun is only 40 more
  than the density of water.
• Density of the sun is 1.4 g/cm3, vs. 1.0 for
  water.

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Convective zone Starts at the bottom of the
photosphere and goes down for about 200k
km. Temperature 6k on the top 2 million on the
bottom! Density gets up to 1/10th the density of
water. Energy is transported through convective
cells.
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http//www.solarviews.com/cap/misc/convect3.htm
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Radiative Zone

• Average density is water.
• This is a stable region, kind of like the
  Stratosphere on the earth.
• Starts 200k km below the photosphere, and ends
  200k km above the center of the sun. That is 50
  of the radius of the sun!
• Energy is transferred by radiation.
• Temperature ranges from 2 to 7 million degrees
  Kelvin!
• How long do you think it takes light to pass
  through the Radiative Zone?

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Time for light to pass through the Radiative Zone

• Light will be scattered from 1 particle to the
  next (sort of like light scattered by water, but
  even worse, and imagine a pool of water about
  400k km deep!).
• Even though light travels at the speed of light,
  it STILL takes 1 MILLION years for a photon of
  light to get through this layer!

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The Core!

• The core is the engine of the sun and is the
  bottom 100-200k km of the sun.
• In the core, the force of gravity is pretty
  intense.
• Here there is a tug of war. Gravity is pulling
  down, and gas pressure and radiative (light)
  pressure is pushing up. The sun has to produce
  lots of energy just to keep itself from
  collapsing under its own weight! This is called
  Hydrostatic Equilibrium.
• Temperature up to 15 million degrees Kelvin!
• Density up to 150 times the density of water!

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Conclusion

• The sun is a wild, crazy, and often violent
  place.
• It has weather that puts any weather the earth
  has to same.
• Coronal mass ejections, if pointed right at the
  earth, can do serious damage to satellites, and
  possibly even our electric grid!