The orbit of planets doesn't directly cause seasons on Earth. It's the tilt of the Earth's axis that's responsible for the change in seasons. Here's why:

* Earth's Tilt: The Earth is tilted on its axis at approximately 23.5 degrees. This tilt means that different parts of the Earth receive varying amounts of direct sunlight throughout the year.

* Summer Solstice: During the summer solstice, the hemisphere tilted towards the sun receives the most direct sunlight, leading to longer days and warmer temperatures.

* Winter Solstice: During the winter solstice, the hemisphere tilted away from the sun receives the least direct sunlight, leading to shorter days and colder temperatures.

* Equinoxes: Twice a year, during the spring and autumn equinoxes, both hemispheres receive equal amounts of sunlight.

While the Earth's orbit is slightly elliptical, it doesn't play a significant role in causing seasons. The tilt of the axis remains constant throughout the year, regardless of the Earth's position in its orbit.

Key takeaway: The tilt of the Earth's axis, not its orbit, is the primary factor responsible for the change in seasons.