Question

Why might we expect Earth to be nearly the same age as its moon and the material that forms meteorites?

Short answer

We expect Earth to be nearly the same age as its moon and the material that forms meteorites because they all originated from the solar nebula approximately 4.6 billion years ago. Earth and the Moon formed through similar accretion processes, while meteorites are remnants from the early Solar System. Since they share a common origin and formed around the same timeframe, it is reasonable to assume Earth, its Moon, and meteorites have nearly the same age.

Step-by-step solution

Origin of Earth, Moon, and Meteorites

All three celestial bodies, Earth, its moon, and meteorites, share a common origin. They formed from the same material, which is the solar nebula, a cloud of gas and dust that resulted from the gravitational collapse of a large molecular cloud. The solar nebula was the birthplace of our Solar System approximately 4.6 billion years ago. As the solar nebula began to collapse and rotate, it eventually flattened into a protoplanetary disk where the materials began to clump together and form various celestial bodies.

Formation of Earth

The Earth formed through a process called accretion. During accretion, dust and gas particles in the solar nebula collided and stuck together, forming larger and larger clumps. As these clumps continued to collide and merge, they gradually grew into planetesimals, and eventually into the size of Earth. This process took about 10 - 20 million years.

Formation of Moon

The most widely accepted theory for the formation of the Moon is the Giant Impact Hypothesis. According to this theory, a Mars-sized object called Theia collided with the early Earth about 4.5 billion years ago. The collision resulted in the ejection of a large amount of debris to form a debris disk around Earth. Over time, the debris particles in this disk came together through a similar process of accretion, eventually forming the Moon.

Formation of Meteorites

Meteorites are remnants from the early Solar System, most of them being leftovers from the formation of the rocky planets and their moons. They formed around the same time as the Earth and Moon, as they are also a product of the same process of accretion that occurred in the solar nebula. The materials accreted to form planetesimals, and some of these leftover planetesimals eventually became meteorites when they did not collide with other objects to form larger celestial bodies.

Timeline of Events

Since all three celestial bodies originated from the same solar nebula and formed through similar processes, it is reasonable to expect that Earth, its moon, and meteorites share nearly the same age. The formation of Earth and the Moon took place around 4.5 - 4.6 billion years ago, and meteorite material formed around the same timeframe. In conclusion, we expect Earth to be nearly the same age as its moon and the material that forms meteorites because they all share a common origin in the solar nebula, and they were formed through similar processes around the same time during the early formation of the Solar System.