Question

The data table shows information about several planets in the solar system.

Distance from Number
the Sun
Average
Surface
of
(1,000,000 km)
Moons
Temperature
79
-150°C
Size
Planet (diameter in km)
Jupiter
Mercury
Neptune
Venus
142,800
4,878
49,528
12,104
778.6
57.9
4,495.1
108.2
0
14
0
260°C
-210°C
465°C
Which planet will orbit at the slowest speed, and why?
O Jupiter; it is the largest planet.
O Mercury; it is closest to the sun.
O Neptune; it is farthest from the Sun.
O Venus; it has the warmest temperature.

Answer 1

Neptune orbits the Sun at the slowest speed because it is the farthest from the Sun, with a distance of 30 AU and a long orbital period of 165 years, resulting in an average orbital speed of 5 kilometers per second.

Step-by-step explanation:

Which Planet Orbits at the Slowest Speed?

The orbital speed of a planet is determined by its distance from the Sun and its orbital period. According to Kepler's laws, the farther a planet is from the Sun, the longer its orbital period and therefore the slower its orbital speed. In the data provided, Neptune is the planet that is farthest from the Sun, at a distance of 4,495.1 million km (or 30 Astronomical Units — AUs), and it takes 165 years to complete one orbit. Compared to other planets such as Jupiter, which is 778.6 million km away from the Sun (5 AU) and has a faster orbital speed due to its shorter orbital period of just under 12 years, Neptune orbits at a much slower speed.

Therefore, the correct answer is 'Neptune; it is farthest from the Sun'. This slowest orbital speed is a result of the planet's large orbital radius and the effects of the gravitational force between it and the Sun as described by Newton's Laws of Motion and Kepler's laws of planetary motion. Neptune's average orbital speed is just 5 kilometers per second, the slowest among the planets mentioned. Size, proximity to the sun, the number of moons, or surface temperature (like that of Venus) do not directly determine orbital speed. Thus, the options suggesting Jupiter's size, Mercury's proximity to the Sun, or Venus's warm temperature are incorrect.