Which of the following statements about comets is true regarding their velocity?

The correct answer highlights the dynamic nature of a comet’s velocity as it travels through space. Comets exhibit elliptical orbits influenced by the gravitational pull of the Sun and other celestial bodies. As a comet approaches the Sun, it speeds up due to the stronger gravitational forces acting upon it, which increases its velocity significantly. Conversely, as it moves away from the Sun, its velocity decreases as the gravitational influence wanes. This varying speed based on its position within the orbit illustrates the difference in velocity throughout its trajectory.

In contrast, the other options do not accurately describe the behavior of comet velocities. For instance, claiming that the velocity is constant throughout their orbit overlooks the fundamental principles of orbital mechanics. Additionally, stating that comets always have a higher velocity than asteroids is not universally true, as it can depend on individual circumstances, including their respective orbits and distances from the Sun. Furthermore, suggesting that comet velocity changes only when near Earth incorrectly simplifies their movement and ignores the broader effects of solar gravity during their entire orbit.