What is the field of study that focuses on Earth's magnetic field called?

The field of study that focuses on Earth's magnetic field is known as geomagnetism. This area of research encompasses the study of the Earth's magnetic field's properties, its variations, and how it interacts with cosmic phenomena such as solar winds. Geomagnetism explores not only the natural magnetic properties of the Earth but also historical changes in the magnetic field and its effects on navigation, geology, and even climate.

Understanding geomagnetism is crucial in various applications, particularly in aviation, where accurate navigation relies on a thorough comprehension of Earth's magnetic characteristics. It provides essential information for navigation systems that depend on magnetic compasses, which are sensitive to variations in the magnetic field.

Other options, while related to magnetic studies, do not specifically address the comprehensive understanding of the Earth's overall magnetic field like geomagnetism does. Magnetometry refers to the measurement of magnetic fields, aeromagnetism pertains specifically to magnetic fields generated in or from aircraft, and magnetoceanography is focused on magnetic phenomena related to oceanography.