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El Nino
Great Lakes
Teacher Info

Gather Data.2

D - Annual Sunspot Numbers

checkmarkClick here to go to the YEARLY AVERAGE SUNSPOT NUMBERS site.

  • Read the legend below the graph for help answering the question.
  1. Since the yearly sunspot number has been calculated using the average of the daily number of sunspots, which solar minimum year had the lowest yearly average? 

E- Math Facts and Solar Measurements

checkmarkClick here to go to the SOLAR FACTS site.

  1. The gravity on Earth is 9.8 meters per second per second.  How much stronger is the gravity on the surface of the sun? 
  2. Escape velocity is how fast you have to go to escape the sun's gravity and not get sucked back into the sun.  What is the escape velocity of the sun in kilometers per hour?
  3. What is the diameter of the sun?
  4. Use the diameter you found in question 3 to find the circumference of the sun. (C = Πd)
  5. Use the rotation period of the sun, the number of hours in a day, the number of meters in a kilometer, and the circumference of the sun to figure out what the surface speed of the sun is in kilometers per hour.  (How fast is it moving on the surface?)
  6. Use the fact that there are about 1.6 kilometers per mile to convert the speed you found in question 5 to miles per hour.


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