Glossary term: Earth's axis

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Description: The Earth's axis is an imaginary line around which the Earth revolves once per day. The points where the Earth's axis intersects with the surface of the Earth are the North Pole at a latitude of 90°N and the South Pole at a latitude of 90°S. The equator is a line on the Earth's surface that is furthest from the Earth's axis. The Earth's axis is tilted by 23.4° compared to the Earth's orbit around the Sun. This tilt is the cause of Earth's seasons. The Earth's axis is slowly precessing, like the axis of a spinning top slowly moving in a circle. This subtly changes the time of year constellations appear in the night sky at over thousands of years and causes slow miniscule drifts in the positions of stars in celestial coordinates.

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The OAE Multilingual Glossary is a project of the IAU Office of Astronomy for Education (OAE) in collaboration with the IAU Office of Astronomy Outreach (OAO). The terms and definitions were chosen, written and reviewed by a collective effort from the OAE, the OAE Centers and Nodes, the OAE National Astronomy Education Coordinators (NAECs) and other volunteers. You can find a full list of credits here. All glossary terms and their definitions are released under a Creative Commons CC BY-4.0 license and should be credited to "IAU OAE".