thumb|right|Late summer dawn over the Mojave Desert, [[California]] thumb|Dawn is sometimes considered the beginning of morning twilight, the period of twilight, or the time of sunrise. Dawn is the time that marks the beginning of twilight before sunrise. It is recognized by the appearance of indirect sunlight being scattered in Earth's atmosphere, when the centre of the Sun's disc has reached 18° below the observer's horizon. This morning twilight period will last until sunrise (when the Sun's upper limb breaks the horizon), when direct sunlight outshines the diffused light.
Dawn is the period of twilight that occurs before sunrise, when scattered sunlight begins to illuminate Earth's atmosphere even though the Sun is still below the horizon. It matters because it marks the transition from night to day and provides a natural division of time that has shaped human activity, navigation, and our understanding of daily cycles.
AI-generated from the Wikipedia summary — may contain errors.
thumb|right|Late summer dawn over the Mojave Desert, [[California]] thumb|Dawn is sometimes considered the beginning of morning twilight, the period of twilight, or the time of sunrise. Dawn is the time that marks the beginning of twilight before sunrise. It is recognized by the appearance of indirect sunlight being scattered in Earth's atmosphere, when the centre of the Sun's disc has reached 18° below the observer's horizon. This morning twilight period will last until sunrise (when the Sun's upper limb breaks the horizon), when direct sunlight outshines the diffused light.
thumb|Civil, nautical, and astronomical dawn, when defined as the beginning time of the corresponding twilight
Discovered by embedding cosine similarity (sentence-transformers MiniLM, 384-dim).