Aroor

Aroor is the early morning period, beginning when faint light appears in the eastern sky and ending when the sun rises. This light originates from the sun being still below the horizon, though its rays reach and scatter through the upper layers of the atmosphere.

The Somali word aroor is also used more broadly to mean early morning generally, for example "aroortii hore" (early dawn). In other languages the phenomenon is called fajr (Arabic), dawn (English), aube (French), and alba (Italian).

Scientific explanation of the light

When the sun is below the horizon, its light still reaches the upper atmosphere. There it scatters off air molecules, and some of this light is reflected back to Earth. For this reason the sky brightens before the sun appears. The same mechanism operates in reverse during evening twilight.

Phases of dawn

Astronomy divides dawn into three stages, measured by how far the sun lies below the horizon. Astronomical dawn is the first moment when any light becomes perceptible. This is followed by nautical dawn, when the horizon at sea becomes distinguishable. Finally, civil dawn marks the point at which there is enough light for outdoor activities without artificial lighting.

Time and location

The duration of dawn varies by location on Earth and season. At the equator dawn is brief, because the sun rises steeply. Near the poles it can last for hours, and at certain times of year for days.

Religious and cultural significance

In Islam, the fajr period marks the beginning of the dawn prayer and the start of the daily fast in Ramadan. In Somali culture, aroor was traditionally when herds were watered and journeys begun, while cooking fires were avoided during the day.