Astronomy 1021 Lecture Notes - Lecture 4: Terrestrial Planet, Impact Crater, Solar Wind

• School: Western University
• Department: Astronomy
• Course: Astronomy 1021
• Professor: Sarah Gallagher

Document Summary

Venus thick atmosphere forces us to explore its surface through radar mapping. Venus has impact crater, but far fewer than mars, mercury and the moon: craters uniformly distributed entire surface same geological age, no small craters: small meteorites burn up in thick atmosphere. Lava plains, shield volcanoes and stratovolcanos on surface: recent evidence that some are active. Venus fractured and contorted surface indicated tectonic stresses, no plate tectonics: entire surface seems to have been repaved about 750 million years ago. All 4 geological processes present on earth. Earth is unique: only terrestrial planet that shows plate tectonics. Seafloor about 200 million years old, compared to 4 billion year old continental rock. Atmosphere is a layer of gas that surrounds a world. Creates pressure that allows liquid to exist. Protects us from dangerous radiation and interacts with solar winds to create magnetosphere. Pressure at the surface (how much gas) =the weight of the atmosphere per square meter.