Geophysics
Physical science of Earth and planetary processes.
Geophysics is a physical science concerned with the processes and properties of Earth and its surrounding space environment, studied using quantitative and observational methods. It focuses primarily on Earth’s shape and its gravitational, magnetic, and electromagnetic fields, as well as internal structure, composition, and dynamics, and their surface expression in tectonics, volcanism, and rock formation. Geophysics also encompasses a broader Earth-system and planetary perspective, including the oceans, atmosphere, cryosphere, ionosphere, magnetosphere, and solar–terrestrial interactions, along with analogous processes on the Moon, other planets, and their satellites.
- field
- Physical science
- known_for
- Study of Earth's gravitational, magnetic, and electromagnetic fields; internal structure and dynamics; planetary and solar-terrestrial interactions
Lore & Background
Geophysics is one of the oldest sciences, dating back to antiquity with the development of early seismometers and magnetic compasses, and later extending to Newtonian analyses of tides, precession, and Earth’s physical properties. Today, geophysics is pursued for fundamental scientific understanding and practical applications, including the exploration of mineral and energy resources, assessment and mitigation of natural hazards, groundwater and environmental studies, archaeological investigations, and environmental monitoring. Geophysics integrates theory, observation, and experiment to investigate Earth and planetary systems across diverse spatial and temporal scales, using methods such as field measurements, laboratory experiments, remote sensing, numerical modelling, and data analysis.
Reader's Guide
Geophysics provides a unifying physical framework for Earth and planetary studies, connecting phenomena from the deep interior to the upper atmosphere and near-space environment. It underpins understanding of planetary evolution, dynamics, and habitability. The discipline contributes to every area of the Earth sciences, with some geophysicists conducting research in planetary sciences. Practical applications include locating mineral deposits through gravity anomalies, exploring for oil and gas using reflection seismology, and assessing earthquake risk through understanding seismic wave mechanisms. Geophysics also informs navigation via Earth's magnetic field, which protects the planet from the solar wind and originates in fluid motions of the outer core. Radioactive decay accounts for about 80% of Earth's internal heat, powering the geodynamo and plate tectonics, and radioactive elements are used for radiometric dating to establish absolute time scales in geochronology.
Did You Know?
- The gravitational pull of the Moon and Sun gives rise to two high tides and two low tides every lunar day, or every 24 hours and 50 minutes.
- Radioactive decay accounts for about 80% of Earth's internal heat, powering the geodynamo and plate tectonics.
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