Here's why:
* Angular Momentum: Angular momentum is a measure of an object's tendency to keep rotating. It depends on the object's mass, velocity, and distance from the axis of rotation (in this case, the sun).
* Conservation: In a closed system (like the Earth-Sun system), angular momentum remains constant.
* Closer to the Sun: As the Earth gets closer to the sun, its distance from the axis of rotation decreases. To maintain constant angular momentum, its velocity must increase.
Think of it like a figure skater spinning. When they pull their arms in, they spin faster. The same principle applies to Earth's orbit.
Key Points:
* Earth's orbit is elliptical, not perfectly circular.
* Earth's speed is highest when it's closest to the sun (perihelion) and slowest when it's farthest (aphelion).
* This speed change is what keeps Earth in its elliptical orbit around the sun.
