Step 2-Finding the Time It Takes for the CME to Arrive 7. This particular CME was not traveling toward Earth. Others, however, occasionally do. The distance between Earth and the Sun is about 1.5 x 10" km. Dividing this distance by the speed of the CME will give the time it takes the CME to arrive at Earth; that is, how much advance notice scientists could have. Consider a similar CME directed at Earth. How many hours would it take a similar CME to reach Earth? How many days would it take a similar CME to reach Earth? Step 3-Considering Uncertainties and Summarizing 8. Your results depend primarily on an accurate measurement of the Sun's diameter, locating the same clump in each of the images, and accurately determining the center of the clump as the material spreads out. Let's consider just the measurement of the Sun's diameter on the image, as that error is systematic-our measurements may be too large or too small, and either way will affect our results. a. What is your original measurement for the diameter of the Sun? _mm b. What would the range of diameters be if your measurement were 25 percent off? (Ex- ample: For the 7-mm diameter given earlier, there would be an uncertainty of 7 mm # 25 percent = 7 mm = 1.8 mm [rounded off ]. The largest diameter would be 8.8 mm; the smallest 5.2 mm. The scale factor would then have a range of 269,000 km/mm for the largest value and 160,000 km/mm for the smallest value.) i. Smallest: ii. Largest: c. What would the range of scale factors be if your measurement were 25 percent off? (Continuing the example from above: If the largest reasonable diameter is 8.8 mm and the smallest is 5.2 mm, then the scale factor would have a range of 269,000 km/mm for the largest value and 160,000 km/mm for the smallest value.) i. Smallest: ii. Largest: d. Continue through the calculations based on the steps above. What would be the range of speeds in kilometers per hour? i. Smallest: ii. Largest: 9. Summarize why it is important that we find a way to calculate the amount of advance notice we have before the material from a violent CME reaches Earth. Why are time and money a wu to nrediet solar flares that grants (MIas