Astronomy Practice Exam 2025 – Complete Preparation Guide

During a lunar eclipse, the correct scenario described is when the Earth blocks sunlight from reaching the Moon. This occurs when the Sun, Earth, and Moon are aligned in a straight line, with the Earth positioned directly between the Sun and the Moon. As a result, the Earth's shadow is cast on the Moon, leading to the phenomenon of a lunar eclipse.

In this process, the Earth's shadow comes in three parts: the penumbra, where partial shadow occurs; the umbra, where total shadow exists; and the antumbra. When the Moon passes through the umbra, it can appear reddish in color, often referred to as a "blood moon," due to Rayleigh scattering—similar to the effect that causes sunsets to appear red when sunlight passes through a thicker atmosphere.

For context, the other options describe different celestial alignments or events. The alignment of the Sun, Earth, and Moon does occur during a lunar eclipse, but it specifically pertains to the Earth's blocking of sunlight. The second option mistakenly suggests that the Moon is blocking sunlight from the Earth, which describes a solar eclipse instead. The last option about the Earth's shadow being cast on the Sun is also incorrect in this context, as this scenario does not happen during a lunar