Astronomy Practice Exam

Which planet is known to be the closest to the sun?

1. Venus

2. Earth

3. Mercury

4. Mars

The correct answer is: Mercury

Mercury is known as the closest planet to the Sun. This is due to its position in the solar system, where it orbits closest to our star, completing its orbit in approximately 88 Earth days. Mercury's proximity to the Sun results in extreme temperatures—very hot on the sunlit side and extremely cold on the dark side—creating a unique environment that differs significantly from those of other planets. This distinction is not just a matter of distance; it shapes many of its physical characteristics and atmospheric conditions. Other options, such as Venus, Earth, and Mars, are positioned farther away from the Sun, with Venus being the second planet, Earth the third, and Mars the fourth. Each of these planets has distinct climates and features that relate to their distances from the Sun.