When is Twilight?


I googled it and it says ‘before sunrise and after sunset’ but I don’t understand how that makes sense because one is AM and the other is PM

In: 1

Twilight is not “an official time” regarding AM or PM, it’s more of just “an amount of light”.

Specifically it’s when the Sun is longer *directly* line of sight from your eyes to the Sun (meaning it’s just below the horizon) BUT some Sunlight is still hitting the atmosphere and reflecting down to you, meaning the sky still has a glow to it.

So basically, Twilight is that time after the sun has set but the sky still has some brightness or that time as the sky begins to get brighter but the sun hasn’t actually risen yet.

‘Twilight’ means not completely light or dark, so it can occur when the sun is rising and when it is setting. It can also mean the way a mostly dark room with one candle looks, or when you are deep underwater in a cloudy lake on a sunny day. It isn’t usually used as a specific time of day, but you could say, for example ‘deer come out early in the day and go to the waterhole at twilight.’

The phrase ‘the twilight zone’ comes from high altitude pilots at the dawn of the space Age. They noticed that as the atmosphere got thinner the sky got darker. The ‘twilight zone’ was the area where it seemed light and dark at the same time.

Twilight is when the sun is below the horizon but the ground is lit from its light scattered in the the atmosphere. The higher parts of the air can see the sun at that point. In the evening twilight happens after sunset, and in the morning before, although I rarely hear this word used in the latter case. Twilight is longer near the Earth’s poles than around the equator because the planet’s rotation makes the sun appear to descend at a more level path.

There is twilight both in the morning and at night. In the morning it is between dawn and sunrise and in the evening between sunset and dusk.

It is the period when you receive sunlight that is scattered in the atmosphere but not in direct sunlight because it is below the horizon.

There are three types of twilight: civil, nautical and astronomical.

Civil twilight is when it remains bright enough so you can do daytime activities outside without artificial light like reading a book.

Nautical twilight is when you can still see the horizon, ships will be a silhouette against the brighter sky behind them.

Astronomical twilight is when there is no scattered light that disturbed astronomical observation. This period will be so dark you call it night.

Today Civil Twilight is when the sun is less than 6 degrees below the horizon. Nautical is less than 12 degrees and astronomical is less than 18 degrees. The origin of the definition of what the text above says

30 minutes before sunrise, and the 30 minutes after sunset.

There are actual legal definitions in different places, for example in the U.K. car headlights have to be used during night, and twilight is defined as 20 minutes before and after sunrise and sunset respectively.