The speed of a planet doesn't depend directly on its distance from the Sun in a simple linear way. Instead, it follows a more complex relationship governed by Kepler's Laws of Planetary Motion.

Here's how it works:

* Kepler's Second Law: This law states that a planet sweeps out equal areas in equal times. This means that a planet moves faster when it's closer to the Sun and slower when it's farther away.

* Conservation of Angular Momentum: The total angular momentum of a planet orbiting the Sun remains constant. This means that as the planet gets closer to the Sun, its speed increases to maintain the constant angular momentum.

To illustrate:

Imagine a planet in an elliptical orbit around the Sun. When the planet is closest to the Sun (at perihelion), it's moving fastest. As it moves away from the Sun, its speed decreases. When it's farthest from the Sun (at aphelion), it's moving slowest.

Why does this happen?

The gravitational force between the Sun and the planet is stronger when the planet is closer. This stronger force causes the planet to accelerate, increasing its speed. As the planet moves further away, the gravitational force weakens, causing the planet to slow down.

In summary:

* Closer to the Sun: Faster speed, stronger gravitational force.

* Further from the Sun: Slower speed, weaker gravitational force.

While a planet's distance from the Sun doesn't determine its speed directly, it plays a crucial role in determining its orbital velocity due to the changing gravitational influence of the Sun.