obliquity

astronomy

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July 1, 2026

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Obliquity refers to the tilt of a planet's axis relative to its orbital plane. For Earth, this tilt is approximately 23.44 degrees and is not constant, varying over tens of thousands of years. This axial tilt is a primary driver of Earth's seasons, influencing how solar radiation is distributed across the planet throughout the year.123

The prevailing hypothesis for Earth's axial tilt suggests a massive collision with a celestial body named Theia early in its formation, which also contributed to the creation of the Moon. The gravitational pull of Earth's moon helps to stabilize this tilt. Obliquity is one of the orbital parameters that influence Earth's climate cycles, particularly over long timescales.12

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astronomy
The Islamic world
…Baghdad astronomers observed that the obliquity of the ecliptic had decreased from the value given in Ptolemy’s Almagest. The obliquity of the ecliptic is the angle between the celestial equator and the tropic of Cancer. It corresponds to the northward displacement of the Sun between the equinox and the summer…
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…Baghdad astronomers observed that the obliquity of the ecliptic had decreased from the value given in Ptolemy’s Almagest. The obliquity of the ecliptic is the angle between the celestial equator and the tropic of Cancer. It corresponds to the northward displacement of the Sun between the equinox and the summer…
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Pleistocene Epoch
Cause of the climatic changes and glaciations
…about 100,000 years, (2) the obliquity, or tilt, of Earth’s axis away from a vertical drawn to the plane of the planet’s orbit, with a frequency of 41,000 years, and (3) the precession, or wobble, of Earth’s axis, with frequencies of 19,000 and 23,000 years. Collectively these parameters determine the…
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…about 100,000 years, (2) the obliquity, or tilt, of Earth’s axis away from a vertical drawn to the plane of the planet’s orbit, with a frequency of 41,000 years, and (3) the precession, or wobble, of Earth’s axis, with frequencies of 19,000 and 23,000 years. Collectively these parameters determine the…
Read More