Chapter 7, Problem 81A

To determine

To identify: Whether the given orbits in the figure are possible orbits for a planet or not.

Explanation of Solution

Given:

The given orbits are:

  

Due to gravitational force, the orbit of a planet is a curved trajectory around the sun.

The planets and satellites nearly follows an elliptical path. The center of the mass of the sun and the planet or the planet and the moon orbits at a focal point of the ellipse.

From Kepler’s law of orbit, all the planets move in an elliptical orbit around the sun having the sun at one of the focus.

The above two orbits do not have the Sun at focus. So, they are not possible orbit for a planet.

The lower left orbit is also not possible because the Sun is not in the orbit.

The only possible orbit is the lower right in which the Sun is at the focus and in the orbit also.