inclination

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inclination

of equator to orbit

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June 29, 2026

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The inclination of Earth's equator to its orbit, known as the obliquity of the ecliptic, is approximately 23.44°. This tilt is not constant and varies between 22.1° and 24.5° over tens of thousands of years. The gravitational pull of the Moon helps stabilize this tilt.12

This axial tilt is the primary reason for the seasons. As Earth orbits the Sun, each hemisphere receives varying amounts of direct sunlight. When a hemisphere leans towards the Sun, it experiences summer due to longer days and increased solar energy absorption. Conversely, the hemisphere tilted away from the Sun experiences winter with less direct sunlight. The equator experiences less pronounced seasonal changes because sunlight strikes it more consistently year-round.3

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Earth
Basic planetary data
44° tilt, or inclination, of Earth’s axis to its orbital plane, also typical, results in greater heating and more hours of daylight in one hemisphere or the other over the course of a year and so is responsible for the cyclic change of seasons.
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44° tilt, or inclination, of Earth’s axis to its orbital plane, also typical, results in greater heating and more hours of daylight in one hemisphere or the other over the course of a year and so is responsible for the cyclic change of seasons.
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Mars
Basic astronomical data
Its axis of rotation is inclined to its orbital plane by about 25°, and, as for Earth, the tilt gives rise to seasons on Mars. The Martian year consists of 668.6 Martian solar days, called sols. Because of the elliptical orbit, southern summers are shorter (154 Martian days) and warmer…
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Its axis of rotation is inclined to its orbital plane by about 25°, and, as for Earth, the tilt gives rise to seasons on Mars. The Martian year consists of 668.6 Martian solar days, called sols. Because of the elliptical orbit, southern summers are shorter (154 Martian days) and warmer…
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Pluto
Basic astronomical data
…the planetary orbits and more inclined (at 17.1°) to the ecliptic, the plane of Earth’s orbit, near which the orbits of most of the planets lie. In traveling its eccentric path around the Sun, Pluto varies in distance from 29.7 AU, at its closest point to the Sun (perihelion), to…
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…the planetary orbits and more inclined (at 17.1°) to the ecliptic, the plane of Earth’s orbit, near which the orbits of most of the planets lie. In traveling its eccentric path around the Sun, Pluto varies in distance from 29.7 AU, at its closest point to the Sun (perihelion), to…
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Saturn
Basic astronomical data
…a small eccentricity (noncircularity) and inclination to the ecliptic, the plane of Earth’s orbit. Unlike Jupiter, however, Saturn’s rotational axis is tilted substantially—by 26.7°—to its orbital plane. The tilt gives Saturn seasons, as on Earth, but each season lasts more than seven years. Another result is that Saturn’s rings, which…
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…a small eccentricity (noncircularity) and inclination to the ecliptic, the plane of Earth’s orbit. Unlike Jupiter, however, Saturn’s rotational axis is tilted substantially—by 26.7°—to its orbital plane. The tilt gives Saturn seasons, as on Earth, but each season lasts more than seven years. Another result is that Saturn’s rings, which…
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Neptune
Moons
…in the solar system are inclined less than about 5° to their planet’s equator, Triton’s orbit is tilted more than 157° to Neptune’s equator. Nereid, which revolves more than 15 times farther from Neptune on average than does Triton, has the most eccentric orbit of any known moon. At its…
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…in the solar system are inclined less than about 5° to their planet’s equator, Triton’s orbit is tilted more than 157° to Neptune’s equator. Nereid, which revolves more than 15 times farther from Neptune on average than does Triton, has the most eccentric orbit of any known moon. At its…
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