The Sun as Seen from the Various Terrestrial Planets. In this exercise, you can use Starry Night Enthusiast™ to examine how big the Sun appears in the sky from the surfaces of all of the inner...

The Sun as Seen from the Various Terrestrial Planets. In this exercise, you can use Starry Night Enthusiast™ to examine how big the Sun appears in the sky from the surfaces of all of the inner planets, starting with Mercury. In order to record your measurements, draw up a Table with the following columns:—Planet Name, Semi-Major Axis of Orbit, (obtained from Appendix E, Table E-1), Angular Radius of the Sun in arcminutes and arcseconds, Angular Radius in arcseconds, and Ratio of Sun Angular Radius. Open the Find pane and ensure that the Query box is empty in order to display a list of the planets. Stop time advance. (a) Click on the Down arrow to the left of Mercury to open the drop-down list and click on Go There to go to the surface of this planet. In the Find tab, double-click on Sun to center the view on the Sun. Now Zoom in () until the Sun fills the view. Use the angle measurement tool of the Hand Tool to measure the angular radius of the Sun from this viewpoint. (Place the Hand Tool over the Sun’s center, hold down the mouse button and move the cursor to the edge of the Sun.) Record the value of this radius, displayed in arcminutes and arcseconds, in your table. (b) Noting the apparent size of the Sun in each “sky” compared to your view from each previous planet, repeat the procedure in section (a) for Venus, Earth and Mars. Qualitatively, how does the Sun change apparent size when going from Mercury to Mars? (c) We will now find a relationship between the angles you measured and the distances of the planets to the Sun. Convert the angular solar radii you have recorded into arcseconds and enter these values in the appropriate column of your table. (1 arcminute = 60 arcseconds) (d) divide the solar angular radius as measured from Earth by its radius at Mercury and record this number. Similarly, divide the Sun’s radius at Earth by the Sun’s radius at Venus, then divide the Sun’s radius at Earth by the Sun’s radius at Earth (this should be 1, of course), and, finally divide the Sun’s radius at Earth by the Sun’s radius at Mars. Verify that these ratios are nearly equal to the values of semi-major axes in your table for each of the planets. If the measurements are not exactly the semi-major axes, explain why. (Hint: draw triangles with the Sun’s radius as one side and the angle from the planet as the opposite vertex and use simple trigonometry.).