Here's why:
* Orbital Velocity and Distance: A planet's orbital velocity is directly related to its distance from the Sun. The closer a planet is to the Sun, the stronger the Sun's gravitational pull, and the faster the planet needs to move to stay in orbit.
* Mercury's Proximity: Mercury is the closest planet to the Sun, resulting in a very strong gravitational pull.
* Mercury's Speed: Mercury orbits the Sun at an average speed of 47.87 kilometers per second (29.78 miles per second).
While other planets have faster instantaneous speeds at certain points in their orbits, Mercury maintains the highest average orbital velocity due to its close proximity to the Sun.
