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Planetary geology

4 dot points across 4 inquiry questions. Click any dot point for a focused answer with worked past exam questions where available.

How does the Earth compare with its rocky planetary neighbours?

The Earth can be compared with its planetary neighbours (the other rocky planets and the Moon) in terms of their rocks and surface materials, surface landforms, atmosphere, surface temperature, pressure and gravity; differences in size, distance from the Sun and the presence of an atmosphere and liquid water explain why the Earth is geologically active and habitable while the Moon and Mars are not, and why some bodies preserve an ancient cratered surface.
A focused answer to the Eduqas GCSE Geology statement on comparing Earth with the rocky planets and the Moon. Covers the comparison of rocks and landforms, atmosphere, surface temperature, pressure and gravity, and why size, distance from the Sun and the presence of an atmosphere and water make the Earth uniquely active and habitable.
13 min answer →

What do the surfaces of the Moon and Mars tell us about their geological histories?

The surfaces of the Moon and Mars record their geological histories: the Moon has heavily cratered highlands and smoother dark maria (ancient basalt plains), showing impact and volcanism on a body that is now dead; Mars shows giant volcanoes, a vast canyon system, dried-up channels and polar ice, showing past volcanism and flowing water; the relative density of impact craters is used to work out the relative ages of different surfaces (more craters means an older surface).
A focused answer to the Eduqas GCSE Geology statement on the Moon and Mars. Covers the lunar highlands and maria and what they record, the volcanoes, canyons, channels and ice of Mars, and how the density of impact craters is used to date planetary surfaces relatively.
13 min answer →

How do meteorites give evidence for the composition of the Earth's interior?

Meteorites are fragments of asteroids and other bodies that fall to Earth; the main types (stony, iron and stony-iron) are thought to sample the interiors of broken-up rocky bodies, so they give evidence for the composition of the Earth's deep interior; iron meteorites support an iron-rich core and stony meteorites a silicate mantle, because we cannot sample the deep Earth directly.
A focused answer to the Eduqas GCSE Geology statement on meteorites. Covers what meteorites are, the three main types (stony, iron, stony-iron), and how they provide evidence for the composition of the Earth's deep interior (an iron core and a silicate mantle) when we cannot sample it directly.
12 min answer →

How does uniformitarianism let us interpret landforms on other planets from space imagery?

Uniformitarianism (the principle that the present is the key to the past, so the same physical processes operate everywhere and at all times) lets geologists interpret the surfaces of other planetary bodies; by comparing landforms seen in space imagery (craters, volcanoes, channels, dunes) with landforms made by known processes on Earth, geologists infer the processes (impact, volcanism, flowing water, wind) that shaped other worlds, even though we have never seen them happen there.
A focused answer to the Eduqas GCSE Geology statement on uniformitarianism applied to planetary geology. Covers the principle that the present is the key to the past, how comparing landforms in space imagery with Earth landforms lets geologists infer the processes (impact, volcanism, water, wind) that shaped other planets, and the limits of the approach.
12 min answer →