Astronomy Practice Exam 2025 – Complete Preparation Guide

The correct choice indicates that a year on Venus is longer than a day. This is a fascinating aspect of Venus's rotation and orbit. A complete rotation on its axis, which is defined as one Venusian day, takes about 243 Earth days, making it the longest day of any planet in the solar system. In contrast, Venus takes approximately 225 Earth days to complete one orbit around the Sun, which defines a Venusian year.

Therefore, when considering the measurement of time on Venus, a single year is indeed shorter than a single day. This unusual relationship between the length of a day and a year on Venus is attributed to its slow rotation and its retrograde rotation direction, which means it rotates in the opposite direction to most planets in the solar system. This unique rotation and orbit lead to the situation where a year on Venus (225 Earth days) is shorter than its day (243 Earth days).

Understanding these timeframes helps highlight the complexities of planetary motion and rotation, revealing that planetary characteristics can lead to counterintuitive results.