There are four different processes that shape planetary surfaces; volcanism, tectonics, erosion, and impact catering. Impact catering is the creation of a bowl-shaped impact crater by asteroids or comets striking a planet’s surface. Volcanism is the eruption of molten rock, or lava from an interior onto its surface. Tectonics is the disruption of a planet’s surface by internal stresses. Erosion is the wearing down or building up of geological features by wind, ice, and other phenomena of planetary weather.
The surface of Mars shows evidence of all four geological processes. It has the tallest volcano and the biggest canyon in the solar system, evidence of a period of great volcanic and tectonic activity. There is also an abundance of craters when looking at the differences between the southern and northern highlands, and evidence of erosion by wind and flowing water. It is likely that the volcanoes on Mars’s surface will erupt again.
Images of dry river channels and eroded craters, along with chemical analysis of Martian rocks, show that water once flowed on Mars. There was once a time where Mars had a climate, warmer temperatures and greater air pressure, that was conducive to water flow and rainfall. However overtime, the water on Mars got saltier and more acidic, changing the climate and thus affecting the ability of liquid water to flow. Any period of rainfall on Mars seems to have ended at least 3 billion years ago. However, Mars still has water ice underground and in its polar caps which could possibly hold liquid water.
Learning about the geology of celestial bodies is so important for our understanding of space. From investigation of all four processes affecting a planet’s surface, one is able to determine the surface conditions and history of planets.