Question

1. Why is the orbital period of each planet not exactly proportional to the radius of its orbit? (Think Kepler's 3rd law).

2. When people say that Venus is the twin of Earth, what is the only characteristic that would validate that statement?

3. If you didn't want to disrupt your sleep cycle, what planet besides earth would you be happy living on?

4. What other terrestrial planet would have seasons similar to earth?

5. Explain the result of Venus' axis being tipped 177 degrees.

Answer 1

1. Kepler's third law states that The square of the period of any planet is proportional to the cube of the semimajor axis of its orbit, and because of the elliptic nature of the orbit, this time eperiod is not direclty proportional to the radius of the orbit.
2. Venus is sometimes called Earth's twin because Venus and Earth are almost the same size, have about the same mass (they weigh about the same), and have a very similar composition (are made of the same material). Also, the acceleration due to gravity on both the planets is close.
3. Mars : A day on mars is 1 day 40 minutes acc to earth day
4. Mars has similiar inclination like that of earth but a year is 1.88 earth years, so smae pattern of seasons with different duration and intensity
5. Due to an axial tilt of 177 deg, the planet venus is upside down (north pole below, and south pole above) when compared to earth and other planets