Learner Express: Modules for Teaching and Learning

Planetary scientist, Prof. Sarah T. Stewart at Harvard University, explains the reasons why craters on Earth are less visible than the ones on its nearest neighbor, the Moon. This is evident even though they are both in the same neighborhood in space. On Earth, whether the impactor hit water or land, processes of erosion have filled in the craters with sediments or eroded them away. In the case of land impacts, craters may also be overgrown with vegetation or filled with water, making them difficult to recognize. Over millions of years, many impact craters in deep ocean basins have been subducted during the process of plate tectonics. The Moon has many more visible craters because it does not have liquid water, an atmosphere, or plate tectonics. Run Time: 00:01:01
Science as Inquiry, 9-12 Standards: Formulate and revise scientific explanations and models using logic and evidence.
History and Nature of Science, 9-12 Standards: Nature of scientific knowledge: Science is a unique way of knowing due to its use of empirical standards, logical arguments, and skepticism. Scientists strive for the best possible explanations about the natural world.