Final answer:
The moon experiences extreme temperature variations due to the absence of an atmosphere, its weak surface gravity, and the porous nature of its soil, leading to rapid heating during the day and cooling at night.
Step-by-step explanation:
The temperatures on the moon vary so much primarily because the moon lacks an atmosphere. This absence means there is no air to help regulate temperature changes between day and night. During the lunar day, temperatures can rise above the boiling point of water because of direct sunlight heating the lunar soil, but at night, the temperature drops significantly to approximately 100 K (-173 °C) due to the colder environment and the moon's surface's ability to rapidly lose heat.
Additionally, the moon's surface gravity is too weak to retain an atmosphere, allowing gases to escape more easily into space. Therefore, any temporary atmosphere provided by phenomena like impacting comets quickly dissipates. Moreover, the moon's dusty soil is porous, which contributes to it cooling faster than solid rock at night.