Kepler's Second Law: A line joining a planet to the Sun sweeps out equal areas in equal intervals of time.
Here's how it works:
* Conservation of Angular Momentum: A planet's orbital motion conserves angular momentum. This means the product of its moment of inertia (which depends on its mass and distance from the sun) and its angular velocity (how fast it rotates) remains constant.
* Closer to the Sun, Faster Orbit: When a planet is closer to the sun, its moment of inertia decreases (smaller distance from the sun). To maintain constant angular momentum, its angular velocity (orbital speed) must increase.
* Further from the Sun, Slower Orbit: Conversely, when a planet is further from the sun, its moment of inertia increases. To maintain constant angular momentum, its angular velocity (orbital speed) must decrease.
In simpler terms:
Imagine a planet moving in a circular orbit around the sun. As the planet gets closer to the sun, it has less space to cover in the same amount of time to sweep out an equal area. Therefore, it must move faster. The opposite happens when it's further away from the sun.
Visual Analogy:
Think of a figure skater spinning. When they pull their arms in close to their body, they spin faster. When they extend their arms, they spin slower. The same principle applies to planets in their orbits around the sun.
