What is defined as the boundary of the Earth's magnetosphere?

The boundary of the Earth's magnetosphere is defined as the point at which the influence of Earth's magnetic field ends and the solar wind begins to dominate. The Earth's magnetosphere is created by the planet's magnetic field, which interacts with charged particles emitted by the Sun—collectively known as the solar wind.

At the magnetopause, which marks the boundary of the magnetosphere, the balance between the pressure from the solar wind and the magnetic pressure from the Earth's magnetic field is established. Inside this boundary, the magnetic field is primarily determined by the Earth's magnetic field alone, while outside of it, the solar magnetic field becomes the dominant force. This region is crucial for protecting the Earth from solar radiation and charged particles.

Understanding this boundary helps explain how the Earth’s magnetic field acts as a shield against solar and cosmic radiation, making the magnetosphere a vital topic in both geology and space science.