Earth science is the study of our home planet: what it is made of, how it works, and how it has changed over its 4.5 billion-year history. Earth scientists study everything from the deepest rocks under our feet to the highest clouds in the sky, plus the oceans, fossils, weather, climate and the slow shifting of the continents. Together they explain how the planet stays alive, where natural disasters come from, and how to find the resources we depend on every day.
- Age of Earth4.54 billion yearsWorked out by radioactive dating of meteorites
- Diameter12,742 kmA little wider at the equator than pole-to-pole
- Layers4Crust, mantle, outer core, inner core
- Tectonic platesApprox. 157 major plates plus several minor ones
- Surface waterApprox. 71%Land is 29%
- Active volcanoesApprox. 1,500On land alone, plus thousands underwater
The main branches of earth science
Earth science is a big subject and most earth scientists specialise in just one part of it.
- Geology: the study of rocks, minerals and the solid Earth, including earthquakes and volcanoes.
- Meteorology: the study of the atmosphere and weather.
- Oceanography: the study of the seas and oceans.
- Palaeontology: the study of fossils and ancient life.
- Climatology: the study of climate and long-term weather patterns.
- Hydrology: the study of fresh water on land, including rivers, lakes and groundwater.
Why earth science matters
Almost every part of human life depends on earth science. It helps us:
- Find the metals, oil, gas and minerals we use every day.
- Predict and protect against earthquakes, volcanoes, hurricanes and floods.
- Manage fresh water supplies and farmland.
- Understand and respond to climate change.
- Track the long history of life on Earth through fossils.
- Choose safe places to build homes, roads and dams.
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