* Kepler's Laws of Planetary Motion: Johannes Kepler, a famous astronomer, formulated laws describing planetary motion. His second law states that a planet sweeps out equal areas in equal times. This means that when a planet is closer to the Sun, it has to move faster to cover the same amount of area in the same time.

* Gravity: The Sun's gravity is the force that keeps planets in orbit. When a planet is closer, the gravitational pull is stronger, causing it to accelerate and move faster.

Think of it like this: Imagine a spinning ice skater. When they pull their arms in, they spin faster. Similarly, a planet closer to the Sun experiences a stronger gravitational pull, which makes it "spin" faster in its orbit.