In astronomy, axial tilt is the angle between a planet's rotational axis at its north pole and a line perpendicular to the orbital plane of the Planet. It is also called axial inclination or obliquity. The axial tilt of Earth is the cause of seasons like summer and winter on Earth.
Axial tilt of major celestial bodies in our solar system [change]
- Sun 7.25 (to the Ecliptic)
- Mercury ~0.01
- Venus 177.4
- Earth 23.439281
- Moon 1.5424
- Mars 25.19
- Ceres ~4
- Jupiter 3.13
- Saturn 26.73
- Uranus 97.77
- Neptune 28.32
- Pluto 119.61
Axial tilt of Venus, Uranus, Pluto [change]
The axial tilts of Venus, Uranus and Pluto are greater than 90 degrees because of following reasons.
- Venus: Venus is rotating in a retrograde direction, opposite to the direction of planets like Earth. The north pole of Venus is pointed 'down' (southward); hence the angle between the rotational axis of Venus passing through its north pole and the line perpendicular to its orbital plane is 177.4 degrees.
- Uranus: Planet Uranus is rotating on its side. The direction of Uranus's rotational axis through its north pole is almost in the direction of its orbit around the Sun, hence its axial tilt is 97.77 degrees. If the direction of its rotational axis had been aligned horizontally with its orbital plane in the direction of its orbit around the Sun, then the axial tilt of the planet would have been exactly 90 degrees.
- Pluto: Like Venus, Pluto's rotational axis and north pole are pointed slightly downward (southward). Hence the angle between Pluto's rotational axis passing through its north pole and the line perpendicular to its orbital plane is 119.61 degrees.