Twilight vs Dusk
Twilight and dusk are often used interchangeably, but they actually refer to different times of the day. Twilight is the period before sunrise and after sunset when there is still some light in the sky. This is due to the diffusion of sunlight below the horizon. There are three types of twilight: civil, nautical, and astronomical. On the other hand, dusk is the darker stage of twilight that marks the end of evening twilight and the beginning of night. There are also three types of dusk: civil, nautical, and astronomical.
Key Takeaways
- Twilight occurs before sunrise and after sunset, when there is still some light in the sky due to the diffusion of sunlight below the horizon.
- Dusk is the darker stage of twilight that marks the end of evening twilight and the beginning of night.
- Both twilight and dusk have three types: civil, nautical, and astronomical.
What is Twilight?
Twilight occurs before sunrise and after sunset, when there is still some amount of light visible in the sky. This light is due to the diffusion of sunlight in the sky, even though the sun is below the horizon. There are three types of twilight: civil, nautical, and astronomical. Civil twilight starts (in the morning) or ends (in the evening) when the sun is 6 degrees below the horizon. Nautical twilight, also known as Military Twilight, starts or ends when the sun is 12 degrees below the horizon. Astronomical twilight starts or ends when the sun is 18 degrees below the horizon.
What is Dusk?
Dusk is defined by the Oxford English Dictionary as the darker stage of twilight. It marks the end of evening twilight and the beginning of night. Dawn is the break of the day, and while the day is yet to start in the twilight, the light we see in the sky is due to the diffusion of sunlight when the sun is still behind the horizon. Twilight occurs before dusk, when there is still some light in the sky even though the sun has gone down below the horizon. There are three types of dusk: civil, nautical, and astronomical. Civil dusk begins with sunset and ends when the geometrical center of the Sun goes 6° below the horizon. Nautical dusk occurs when the Sun goes 12° below the horizon in the evening. Astronomical dusk is the instant when the geographical center of the Sun is at 18° below the horizon.
What is the difference between Twilight and Dusk?
- Twilight occurs twice in every 24 hours, around dawn and dusk, and is characterized by soft, diffused light in the sky despite the sun being below the horizon.
- Twilight is commonly associated with sunset, but the same phenomenon occurs during sunrise as well, before daybreak.
- Dusk marks the beginning of night and the end of the day, as twilight also ends and there is no light in the sky.
- Dusk is a part of twilight, indicating that twilight is ending and there is very dim light or no light in the sky.
