Magnetosphere

/mæɡˈniːtoʊˌsfɪər/ noun

Definition

The region around Earth dominated by its magnetic field, extending from about 1,000 kilometers altitude to over 60,000 kilometers on the sunward side. The magnetosphere deflects most solar wind particles and cosmic rays.

Etymology

From Greek 'magnetos' (magnet) and 'sphaira' (sphere), coined in the 1950s as scientists recognized Earth's magnetic influence extends far into space. The term was popularized during early space exploration as this invisible shield's importance became clear.

Kelly Says

Earth's magnetosphere is constantly changing shape like a cosmic windsock! On the Sun-facing side it's compressed to about 10 Earth radii, but on the night side it stretches into a tail that extends beyond the Moon's orbit, flapping and reconnecting as solar wind conditions change.

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