Chapter 6 Flashcards
Intercrater plains
Regions on the surface of Mercury that do not show extensive cratering but are relatively smooth.
Scarp
Surface feature on Mercury believed to be the result of cooling and shrinking if the crust forming a wrinkle on the face of the planet.
Shield volcanoes
A volcano produced by repeated nonexplosive eruptions of lava, creating a gradually sloping, shield-shaped low dome. Often contains a caldera at its summit.
Coronae
One of numerous large, roughly circular regions on the surface of Venus, thought to have been caused by upwelling mantle material causing the planet’s crust to bulge outward (plural, coronae)
The tenuous outer atmosphere of the Sun, which lies just above the chromosphere and, at great distance, turns into the solar wind.
Runoff channels
Riverlike surface feature on Mars, evidence that liquid water once existed there in great quantities. They are found in the southern highlands and are thought to have been formed by water that flowed nearly 4 billion years ago.
Outflow channels
Surface feature on Mars, evidence that liquid water once existed there in great quantity; believed to be the relics of catastrophic flooding about 3 billion years ago. Found only in the equatorial regions of the planet.
Permafrost
Layer of permanently frozen water ice believed to lie just under the surface of Mars.
Secondary atmospheres
The chemicals that composed Earth’s atmosphere after the planet’s formation, once volcanic activity outgassed chemicals from the interior.
Carbon cycle
Chain of reactions that converts hydrogen into helium using carbon, nitrogen, and oxygen as catalysts
Runaway greenhouse effect
A process in which the heating of a planet leads to an increase in its atmosphere’s ability to retain heat and thus to further heating, causing extreme changes in the temperature or the surface and the composition of the atmosphere.
