Page:Illustrated Astronomy.pdf/37



• • • SUMMARY SELF-TEST

In the next link or QR code you can find Sun pictures taken in different days and the date they were shot.

And by using them:

1 · Calculate the rotation speed of the Sun.

2 · About what speed (in km/h), something on the Sun surface would move (at its Equator)?

3 · Compare that speed to the one we experience on the Earth’s surface.

· Have in mind that the radius of the Sun is 700,000 km.

If you don’t know how to start, we give you the following clues:

CLUE 1: You can calculate the motion of every spot using the grid in the QR code downloaded. To do so, follow the motion of every spot and calculate how many degrees does the spot move per day.

CLUE 2: If you have already calculated the angular distance per day, you can calculate how much it will take to complete the 360° of the solar sphere.

CLUE 3: Everything can be simplified with a higher margin of error. You can get the highest values of the day in which a spot appears and how long it takes to disappear. As it traveled halfway through the Sun (the part we can see), the total travel time has to be twice. • • • 37