Question #11:Figure 3 shows the earth-sun-venus system with the earth's position shown on the date of the first Venus photo (January 19). Use the data shown in the scanned image to find the location of Venus on the observation dates listed below. This must be done in several steps.

a.) First you need to determine where the earth is on the observation dates. Make a table like the one shown below.

Date

Jan. 19

Feb. 20

Mar. 21

Apr. 13

May 8

Days Elapsed since Jan.19

0 32

The left-hand column shows the dates on which the observations were made. The right- hand column shows how much time has elapsed since the Jan. 19 observation. For example, Feb. 20 is 32 days later than Jan. 19. Recall that the earth travels one degree in one day. Complete the table for the remaining observation dates.

b.) Draw, directly on Figure 3 and as accurately as possible, the positions of the earth on each of the observation dates.

c.) Next, draw as accurately as possible the positions of Venus on the observation dates. To do this, you will need to use information contained in the scanned image below 'Figure 1: Observations of venus.'; the telescope observations tell you how the size and illumination (by the sun) of Venus changes. From this, you can determine the relative positions of the earth and Venus.

d.)Based on your results, estimate the length of the venusian year. How close where you to the actual value of the venusian year?

Jam C ( Figure 1: Observations of venus. From left to right, observations are made on (top row) Jan. 19, Feb. 12, Feb. 20; (second row) Mar. 1, Mar. 9, Mar. 21; (third row) Mar. 27, Apr. 4, Apr. 13, (bottom row) Apr. 23, Apr. 30, May 8, 2001. North is up. (From http://www.calvin.edu/academic/phys/observatory.) Dec