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.
(a) With few ticks, moose retain a brown coat; (b) at high numbers of ticks, moose self-groom, destr
Place the infant faceup on a soft surface, such as a towel, and remove his or her clothing. With one ...
Foundations of Earth Science, 7th Edition
Earth’s Spheres
Surface Salinity of the Oceans
Early Earth