sidérales

Sidérales is a term that can refer to several related concepts, primarily in astronomy and sometimes metaphorically. In its most common astronomical usage, sidérales pertains to measurements made with respect to the stars. This is particularly relevant in the context of timekeeping. A sidereal day, for example, is the time it takes for the Earth to complete one rotation relative to the fixed stars, which is slightly shorter than a solar day (the time it takes to rotate relative to the Sun). This difference is due to the Earth's orbital motion around the Sun.

The term is also used in relation to measurements of celestial objects. Sidereal coordinates, for instance, are a system of celestial coordinates used to specify the positions of stars and other astronomical objects in the sky. These coordinates are fixed relative to the distant stars, providing a stable reference frame for mapping the cosmos.

Metaphorically, "sidérales" can be used to describe something that is vast, immense, or seemingly infinite, evoking the boundless nature of outer space. This usage often implies a sense of awe or wonder, drawing a parallel between the immeasurable distances of the universe and the scale of a particular concept or quantity. For example, one might speak of "sidereal distances" to emphasize the enormous scale of separation between celestial bodies.