A planet's velocity at aphelion is its speed at the point in its orbit where it is farthest from the sun. This is also known as the planet's maximum orbital velocity.
A planet's velocity at aphelion can be calculated using the formula v = √(GM(2/r - 1/a)), where v is the velocity, G is the gravitational constant, M is the mass of the sun, r is the distance from the planet to the sun at aphelion, and a is the semi-major axis of the planet's orbit.
A planet's velocity at aphelion is affected by the mass of the sun, the distance between the planet and the sun at aphelion, and the shape of the planet's orbit. The more massive the sun and the farther the planet is from it at aphelion, the higher the velocity will be.
Knowing a planet's velocity at aphelion is important for understanding its motion and behavior in its orbit. It can also help in predicting future positions of the planet and determining its overall orbital stability.
Yes, a planet's velocity at aphelion can change over time due to various factors such as gravitational interactions with other objects, changes in the shape of its orbit, and the influence of other forces like radiation pressure.