Trough or ridge; crater of life and death

It is the same photograph, yet one view appears to show a trough and the other a ridge. The difference is the direction of light. Without familiar objects, our brains cannot reliably determine the correct three-dimensional view. These two long structures can appear inverted when you turn the image upside down. How can you tell which view is correct? Impact craters are always depressions. Find one to help interpret the relief.

Draw the crater’s details using the descriptions on the left. Which setting do you choose: Earth, ancient Mars or present-day Mars? The crater is a round, flat-bottomed depression surrounded by steep slopes. It is a larger crater and therefore has a central peak.