Planetary geology
5 questions tagged Planetary geology — spanning every one of the seven Ws.
What is a crater on a planet or moon?
A crater is a bowl-shaped depression formed by impact from a meteoroid, asteroid, or comet.
Whose work first measured the age of the Moon from rocks returned from space?
Scientists including Clair Patterson and colleagues helped date Moon rocks in the Apollo era. The oldest lunar samples are about 4.5 billion years old.
How do scientists know the age of a crater on the Moon?
They count impact craters on the surface and compare the crater’s appearance with samples and known geological timelines. Apollo samples helped anchor the Moon’s impact history to real ages.
What is a cryovolcano?
A cryovolcano is a volcano that erupts icy or slushy materials instead of molten rock. They are thought to exist on icy worlds such as moons and dwarf planets.
Where is the largest canyon in the Solar System?
It is Valles Marineris on Mars. The canyon system stretches about 4,000 kilometers across the planet.