Animation illustrates the planets Mercury, Venus and Earth revolving round the Sun. The distances and times of motion are scaled correctly. You should be able to notice that while orbits of Venus and Earth are nearly circular (The eccentricities of their orbits are 0.0068 and 0.0167 respectively), the orbit of the innermost planet Mercury has noticeable ellipticity. ( It has an eccentricity of 0.2056 ). The semi major axes of the orbits of the three planets are 0.3871, 0.7233 and 1 A.U. respectively. Time the periods of revolution of each planet by watching its motion and find the ratio of square of time period and the cube of semi-major axis for each planet. You would find the ratio to be a constant. It may be convenient to express the time of revolution in terms of a year and the semi major axis in terms of A.U., so that this constant is 1 for the planet Earth. Obviously the constant would be 1 for the remaining two planets also.
Option 1 causes planets to stop after one revolution of mercury.
Option 2 causes planets to stop after one revolution of venus.
Option 3 causes planets to stop after one revolution of earth.
Option 4 lets them all revolve continously.
| Planet |
Period of
revolution |
Period of
rotation |
Semi
major
axis (AU) |
Eccentricity
|
around sun
(in Years) |
around own
axis |
| Mercury |
0.241 |
58.6 days |
0.387 |
0.206 |
| Venus |
0.615 |
243 days |
0.723 |
0.007 |
| Earth |
1.00 |
23 h 56 m 4 s |
1.00 |
0.017 |
| Mars |
1.88 |
24 h 37 m 23 s |
1.524 |
0.093 |
| Jupiter |
11.86 |
9 h 50 m |
5.203 |
0.048 |
| Saturn |
29.46 |
10 h 25 m |
9.54 |
0.056 |
| Uranus |
84.01 |
710 h 50 m |
19.18 |
0.04 |
| Neptune |
164.79 |
16 h |
30.07 |
0.008 |
| Pluto |
248.43 |
6.4 days |
39.44 |
0.249 |