Final answer:
The process that occurs when an extraterrestrial body impacts the Earth is called shock metamorphism, a type of geological activity involving instantaneous and high-pressure metamorphism at the impact site.
Step-by-step explanation:
When an extraterrestrial body, such as a meteorite or comet, impacts with the Earth, the process that occurs is known as shock metamorphism. This geological activity is a result of the external force caused by the impact, which leads to the transformation of rocks due to the intense pressure and heat generated upon collision. Unlike processes such as regional metamorphism, which are related to large-scale changes over vast areas due to tectonic forces, shock metamorphism is nearly instantaneous and is typically confined to the immediate area surrounding an impact site.
This type of metamorphic change can create unique geological structures, such as shatter cones, and impact-induced minerals that are not found in any other natural setting. Moreover, impact events have played a significant role in the history of Earth, contributing to geological and biological evolution, as emphasized by paleontologist Stephen Jay Gould. It is a process distinct from exogenic processes like weathering and erosion, or internal processes like earthquakes and volcanism, that shape the planet's surface over longer timescales.