Geophysics

Geophysics is a physical science that studies Earth and its surrounding space environment. It looks at Earth’s shape, as well as its gravitational, magnetic, and electromagnetic fields. Geophysicists study Earth’s internal structure, composition, and how it moves and changes, including processes like tectonics, volcanism, and the formation of rocks.

This science has a long history, going back to ancient times with early tools like seismometers and magnetic compasses. Today, geophysics helps us understand Earth in many ways. It is used to find mineral and energy resources, assess and reduce natural hazards, study groundwater and the environment, investigate archaeological sites, and monitor environmental changes.

Geophysics combines theory, observation, and experiment to study Earth and other planetary systems. Scientists use field measurements, lab experiments, remote sensing, numerical modeling, and data analysis to explore phenomena from deep inside Earth to the upper atmosphere and near-space environment. This science provides a foundation for understanding planetary evolution, dynamics, and habitability.

Physical phenomena

Geophysics is a science that studies the Earth and its surroundings using physical methods. Geophysicists look at the Earth’s shape, its gravity, and its magnetic fields. They also study how the Earth moves and changes over time, like earthquakes and how rocks form.

Geophysicists examine many different things. They study gravity, which helps us understand the Earth’s shape and find useful minerals. They also study vibrations in the Earth, like those from earthquakes, to learn about the inside of the planet. Other areas include electricity and magnetism in the Earth, heat from radioactive elements, and the movement of fluids like water and air. All these studies help us understand how the Earth works and how it has changed over time.

Main article: Gravity of Earth

Further information: Physical geodesy and Gravimetry

Main article: Seismology

Main article: Geophysical fluid dynamics

Main article: Geothermal gradient

Main article: Mineral physics

Regions of the Earth

Size and form of the Earth

The Earth isn’t a perfect sphere. It is closer to an ellipsoid shape because of how it spins. This makes it bulge a bit around the Equator. The Earth’s shape changes over time because of melting ice, mountains, ocean trenches, tectonic plate movements, and natural disasters.

Structure of the interior

Main article: Structure of Earth

By watching how waves from earthquakes move through the Earth, scientists have learned about its layers. The Earth is denser inside than on the surface, with a core made mostly of iron. The outer core is liquid, while the inner core is solid because of huge pressure. The layers include the lithosphere, crust, mantle, and core.

Magnetosphere

Main article: Magnetosphere

The Earth’s magnetic field makes a shield called the magnetosphere. This shield stretches far into space and helps protect the planet from harmful particles from the Sun. Inside this shield are areas called the Van Allen radiation belts, which hold many charged particles.

Methods

Main article: Geodesy

Geophysics uses special tools to study Earth. One important tool is geodesy. It measures Earth’s shape and changes. Scientists often use the global positioning system (GPS) to find exact locations. They can also use satellites to measure Earth’s gravity.

Satellites help scientists study Earth and other planets. By tracking how spacecraft move, scientists can map the gravity fields of planets. These tools let us see and measure Earth and space in new ways.

Main article: Remote sensing

Main article: Signal processing

Further information: GIS

History

Main article: History of geophysics

Geophysics became a science in the 1800s. It mixes ideas from physical geography, geology, astronomy, weather science, and physics. People have studied Earth's magnetic field and earthquakes for a very long time. For example, the magnetic compass was used in China over 2,000 years ago. A Greek scientist named Eratosthenes measured around the Earth very accurately long ago.

In the 1600s, big steps were taken in science. William Gilbert showed that Earth acts like a giant magnet. This explains why compasses point north. Later, Isaac Newton wrote important books. These books helped explain how gravity works and how objects move. They also helped us understand Earth better. The first machine to record earthquakes was made in 1844.