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Goal: To understand how the sun works. Objectives: Journey to the center of the sun!. Spaceship Sol. Scheduled departure time: 5 min. Please fasten seatbelts. What color is The sun? Yellow Orange Blue White Red. Spaceship Sol. Scheduled departure time: 4 min. Prepare for departure.
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Goal: To understand how the sun works Objectives: Journey to the center of the sun!
Spaceship Sol • Scheduled departure time: 5 min. • Please fasten seatbelts. What color is The sun? • Yellow • Orange • Blue • White • Red
Spaceship Sol • Scheduled departure time: 4 min. • Prepare for departure. Is the sun a “star”? • Yes • No
Heliosphere: Solar Wind speed: 390.0 km/s density: 7 protons/cm3 Outside temp: 292K 68 F Density outside: Almost 0.
Outside temp: 400K 262 F Density outside: 10 protons/cm3
Outside temp: 450K 352 F Density outside: 28 protons/cm3
Outside temp: 604K 618 F Distance to sun: 20 million miles Density outside: 140 protons/cm3
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
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
Corona Outside temp: 1 million K! 100k miles from the surface
Chromosphere Outside temp: 10000K 1k miles from the surface CORONAL MASS EJECTION!!!
Rotation of the sun. The sun rotates every 26-28 days, depending on where on the sun you are. Why could this be important?
Photosphere Outside temp: 5800K Surface! Density: 1% of air. All of the sun’s light that we see comes from here. Question: If we fly in onto that sunspot, will it be dark or light?
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 of boiling water.
Welcome to the sun!http://www.nasa.gov/mpg/118091main_other_loop_sm.mpg
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?
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
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.
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.
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?
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!
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. • Temperature: up to 15 million degrees Kelvin! • Density: up to 150 times the density of water!
Hydrostatic Equalibrium • Here there is a tug of war. • Gravity is pulling down • Gas pressure and radiative (light) pressure are 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. • Very special and important things happen when this equilibrium are broken, but more on that later in the course
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!