INTRODUCTORY ASTRONOMY: THE SOLAR SYSTEMLABORATORY ASSIGNMENT - Kepler and the Laws of Motion of the Planets

Hypothesis

Kepler's assertion that all planets and celestial objects observed to move, do so in elliptical orbits.

Question Asked: How can we empirically prove Kepler's 3rd Law?

Discussion

1. As you zoom in and out, you can also start playing with time! Press the L key to move time forward, do this several times until you see the planets moving.

Tips:

a. If you find that you are going too fast, press the K key to stop all motion and return you to normal time.

b. You can always press the number 8 to return you to the present day.

c. To go backwards in time, press the J key.

2. What can you observe of the planets motion?

What is the relationship between the distance from the Sun and the speed at which the planets seem to move?

3. Of the three laws, which law best describes this relationship? How?

4. In the next part, we will be observing each planet's orbital period (P) and Semi-major axis (a) and using this information, we will be proving that the ratio in Kepler's 3rd Law is indeed 1.

5. Let us begin by stopping all motion and returning to present day. (Press K and 8)

6. We will start the exercise by zooming in on the planet Mercury's orbit. Make sure it fills the screen, but you are still able to see the entire orbit itself.

7.  Place a finger, or a piece of paper with tape to mark the position of Mercury on your screen. Note the start date on the table below.

8. Press the L key to move time forward. No more than 7 presses should do it.

9. When Mercury returns to its original starting point not the end date in the table below.

10. Enter the amount of days it took for Mercury to complete one orbit. Convert this number into the equivalent amount of Earth years by dividing your finding by 365.25 days.

11. Repeat this measurement for each of the planets in order. (We will not be measuring Pluto!)

12. To find the distances that the planets are from the Sun, we must first go to the Sun!

a. Use the CTRL-F or F3 keys to find the Sun. Then travel to the Sun by pressing CTRL-G

b. Now, all you have to do is search each planets name in turn (again CTRL-F or F3) and obtain their distance information in au fromthe informational chart on the upper left hand of your screen.

13. Fill in the information in the table below, and perform the necessary math indicated in each row. (round to the nearest hundredth -> two decimal points, ex: 8.9341=8.93).

Attachment:- Assignment.rar