Astronomy Practice Exam 2025 - Free Astronomy Practice Questions and Study Guide

The third planet from the Sun is Earth. In our solar system, planets are arranged in the following order from closest to furthest from the Sun: Mercury, Venus, Earth, and then Mars. Earth is the only planet known to support life, with its unique atmosphere and water in liquid form, making it distinct among the other planets. Understanding this order is fundamental to learning about solar system dynamics and the characteristics of each planet, including their orbits and relative distances from the Sun.

Recognizing Earth's position as the third planet helps contextualize its climate, seasonal changes, and its orbit around the Sun, which takes approximately one year to complete. This knowledge contributes to an overall understanding of the solar system's structure.