Author Question: Compare the surface of Earth to that of the moon. Why doesn't Earth's land retain the same scarring ... (Read 140 times)

Evvie72 · **on:** Jul 15, 2018

Compare the surface of Earth to that of the moon. Why doesn't Earth's land retain the same scarring from meteorite impact as the moon? Why doesn't Earth's ocean retain the same scarring from meteorite impact?

What will be an ideal response?

Question 2

Using the nebular theory, explain the formation of our solar system from the formation of the solar nebula through the present day.

What will be an ideal response?

Jbrasil · **Reply #1 on:** Jul 15, 2018

Answer to Question 1

Answer: Earth has liquid water and an atmosphere, which help weather away evidence on the surface. However, oceans primarily cover the surface of Earth, which means that there would be a greater likelihood of a meteorite falling in the ocean. There is not a great deal of meteorite impact evidence preserved on the ocean floor because the ocean crust is continually subducting. The oldest part of the seafloor is no more than 200 million years old, which is significantly younger than the timing of the great bombardments in early Earth's history. The moon has no processes of weathering to remove such evidence.

Answer to Question 2

Answer: The gases and dust in the solar nebula contracted and began to rotate. The majority of materials fell into the center of this rotating mass to form the protosun. The remaining materials flattened out into a disk, which allowed heat to escape more quickly. Cooling resulted in condensation of larger grains of icy, rocky material. These grains collided repeatedly to create protoplanets, which eventually became the planets we have today.