Obliquità

Obliquità is a term used in various fields to describe a departure from the perpendicular or the horizontal. In geometry, it refers to an angle that is not a right angle (90 degrees). For instance, an oblique line intersects another line or plane at an angle other than 90 degrees. This contrasts with perpendicular lines, which intersect at a right angle.

In astronomy, obliquity specifically refers to the angle between a celestial body's equatorial plane and its orbital plane. The Earth's obliquity, also known as its axial tilt, is approximately 23.5 degrees. This tilt is responsible for the seasons, as different hemispheres receive more direct sunlight at different times of the year. The obliquity of other planets also influences their seasonal variations.

The concept of obliquity can also be applied metaphorically to describe something indirect or not straightforward. An oblique statement, for example, might be one that is not directly expressed but hinted at. In art and design, oblique lines can be used to create a sense of dynamism or tension, deviating from the stability of vertical and horizontal elements. The term generally conveys a sense of slant, angle, or indirectness.