Concepts in Astronomy #16. Axial Tilt

Axial Tilt

The axial tilt or obliquity is the angle between the orbital plane and the equatorial plane of a planet. It can also be described as the angle between the rotational axis and a perpendicular line to the orbital plane. The Earth's axial tilt is currently 23.44°. This angle varies between 22.1° and 24.5° in a period that lasts 41000 years.

The axial tilt is responsible for the existence of seasons because it allows one hemisphere to receive more sunlight than the other hemisphere for a determined amount of time in a year (orbital period).

Previous Posts

Concepts in Astronomy #1. Introduction
Concepts in Astronomy #2. The Ecliptic
Concepts in Astronomy #3. The Celestial Equator
Concepts in Astronomy #4. Right Ascension
Concepts in Astronomy #5. Declination
Concepts in Astronomy #6. The Celestial Sphere
Concepts in Astronomy #7. Azimuth
Concepts in Astronomy #8. Altitude
Concepts in Astronomy #9. The Equatorial Coordinate System
Concepts in Astronomy #10. The Topocentric Coordinate System
Concepts in Astronomy #11. Equinox
Concepts in Astronomy #12. Solstice
Concepts in Astronomy #13. Rotation Period
Concepts in Astronomy #14. Orbital Period
Concepts in Astronomy #15. Axial Precession

Credits

- Galaxy image obtained from Pixabay under CC0. No Copyright. The person who associated a work with this deed has dedicated the work to the public domain by waiving all of his or her rights to the work worldwide under copyright law, including all related and neighboring rights, to the extent allowed by law

- Axial Tilt image obtained from Wikipedia under CC BY-SA 3.0. Author: Dennis Nilson