Question

All planets move in _____.

• A. straight paths
• B. elliptical paths
• C. circular paths
• D. hyperbolic paths

Answer 1

The correct option is B

elliptical paths

Explanation for correct options:

Option (b) elliptical paths

Kepler's First Law:

1. Kepler's First Law states that the orbit of each planet around the Sun is an ellipse.
2. The Sun's center is always at one of the orbital ellipses' foci.
3. The planet's orbit is elliptical, which means that the planet's distance from the Sun changes as it travels around its orbit.
4. Perigee is the time in a satellite's orbit when it is closest to the planet Earth.
5. Apogee is the period when the satellite is the farthest away from the Earth.
6. All of the planets' orbits are elliptical, but the eccentricities are so slight that they appear circular, except for Pluto and Mercury, which have more elliptical routes that appear more eccentric.
7. So, this option is correct.

Explanation for incorrect options:

Option (a) straight paths

1. This option is incorrect.
2. As according to Kepler's first law the planets revolve around the sun in an elliptical pathway.

Option (c) circular paths

1. Kepler was eventually obliged to admit that the planets' orbits are not circles, but rather ellipses, which are elongated or flattened circles.
2. Hence, this option is also wrong.

Option (d) hyperbolic paths

1. This option is not correct.
2. Because the path in which planets revolve is elliptical in shape and not hyperbolic.

Therefore, all planets move in elliptical paths.

Hence, option (B) is the correct answer.