Twilight — The Time Between Daylight and Darkness

Twilight: It’s not just a book series, but also marks the time between daylight and darkness. Where does it fit into our lives and should you be waking up and going to bed in the “twilight zone?”

 

You look out your window and see a gorgeous sunset with delightful hues of orange and a stray streak of pink. It will be night soon. You get a strange idea:

 

I’ll watch the sunset until it becomes nighttime!

 

You watch and watch. The painted sky becomes a bit grayer, a bit less grand, but it is certainly not night yet. Eventually, your computer beeps, an email arrives, or your phone takes you away for a minute or two. When you look back, it has become night. You realize that the time between daylight and darkness — when the sun gives way to the moon — is a bit elusive. So when is it? When does day become night and night become day?

 

One Day, Six Twilights

Scientists, horologists, astronomers, and poets alike have a name for the time between daylight and darkness. It’s called “twilight” and happens twice a day, once to start the morning and once to start the night. Unfortunately, as you might’ve noticed, the time between daylight and darkness is a sort of spectrum. Since the Earth is curved, and light diffuses, there is no singular moment or switch from day to night.

 

As a result, the term “twilight” is only so useful. When specifics are needed, the three distinct types of twilight (civil, nautical, and astronomical) are used.

 

 

As can be seen in the image above (Credit: National Weather Service) we first experience astronomical, then nautical, and finally civil twilight in the mornings. At night, we first experience civil, then nautical, and finally astronomical twilight. Each day, there are six twilights.

 

To remember the order of twilights, use a simple mnemonic. In the morning we use our ANC (Active Noise-Cancellation) headphones to enjoy a peaceful sunrise. At night the CNA (Certified Nursing Assistant) gets ready to go to work. Alternatively, read on to learn more about each of the types of twilight and get a more in-depth understanding of why they are called what they are:

 

Civil Twilight

Civil twilight is the first stage in the time between daylight and darkness. During civil twilight, the sun is just below the horizon but you are likely to be able to see objects without artificial lighting. Bright stars and planets can also be seen. This type of twilight gets its name because its duration is the earliest and latest humans on land can function without electricity, fire, or other sources of artificial lighting. In other words, it marks the start and end of the day for most people.

 

While, when compared to those living in ancient times, civil twilight is less important for modern humans that have near-constant access to artificial light, it is still an important time to consider. Sunrises and sunsets, which respectively happen just after and before the civil twilights of day and night, cause danger to drivers due to glare from the horizon-adjacent sun. So, if you start driving during the morning’s civil twilight, try to arrive at your destination before the sun pokes its head over the horizon.

 

Equatorial cities, such as Singapore, have about 40-45 minutes of civil twilight each day, split up evenly between when the sun rises and when it sets. As we near the middle longitudes, civil twilight times increase, with cities in Florida getting around 45-55 minutes of civil twilight (again, split up roughly evenly between sunrise and sunset) each day. Near the poles, civil twilight completely disappears for part of the year. For example, Longyearbyen, Norway gets no civil twilight from about mid-November to the end of January.

 

Nautical Twilight

Nautical twilight is similar to civil twilight but for the sea. At this time, if you’re at sea, you have the possibility of taking measurements with the available stars and might be able to make out the outlines of landmasses.

 

It was approximately 11:40 PM when the Titanic hit the iceberg. That’s two hours after nautical twilight in Newfoundland, near where the accident occurred. What if the “unsinkable ship” had reached the area of its demise two hours earlier? Would the captain have seen the iceberg then? Would Celine Dion be slightly less famous? The world may never know.

 

Astronomical Twilight

The last type of twilight is astronomical twilight, which occurs nearest to darkness. Even less useful to ordinary citizens than nautical twilight, you are unlikely to even notice that astronomical twilight is ongoing with the unaided eye.

 

Instead, think of the day’s astronomical twilights as “opening time” and “closing time” for astronomers. During astronomical twilight, their equipment can make out some — but not all — of the features of the night sky. Oddly enough, for the most dedicated, telescopes can be used during the day. Still, you gotta quit some time, so why not let it be astronomical twilight for your eyes’ sake?

 

To check the twilight times in your city, ClockHug recommends using Timeanddate’s calculator.

 

 

Dawn

Dawn is the period when the first light of the sun begins to appear on the horizon, marking the beginning of the day. It happens after the twilight that happens in the time between darkness and daylight.

 

This is a time of transition, not just for the sky, but for many people as well. It is the time of day when many people wake up to start their day, often using an alarm clock to rouse themselves from sleep. Waking up can be challenging for some, but the energy and inspiration associated with dawn can make it an enjoyable process.

 

Whether waking up early to catch the sunrise, the otherworldly morning fog, or taking a moment to reflect on the beauty of the early morning, dawn is a time of day that holds great significance for many.

 

Dusk

Dusk is the period when the sun has set below the horizon, and the sky begins to transition from light to dark. It happens after the twilight that happens in the time between daylight and darkness.

 

As fewer people go to bed at dusk as wake up near dawn, dusk is less of a period of transition for humans than it is for other species. Still, dusk can signify a time to unwind after a long day. The natural world also begins to wind down at dusk, though crepuscular animals like cats will have a noticeable uptick in activity.

 

As dusk turns into night, many people begin to think about sleep and the rest that it brings. However, for some, the thought of sleep can be daunting or even frustrating. Some people may feel that sleep is a waste of time, or that they would rather stay up late to accomplish more. Others may procrastinate going to bed, putting it off in favor of other activities. Whatever the reason, the transition from dusk to night can be a time of mixed emotions for many people, as they prepare for the rest and rejuvenation that sleep can bring.

 

 

Sunsets, Morning and Night

As mentioned in the above segments, we typically associate the sky changing colors with the impending change from the later twilight to dusk. This segment of the time between daylight and darkness lends itself to beautiful colors due to light refraction on the atmosphere of the Earth.

 

But what about in the morning? Is there a morning equivalent of a sunset?

 

In some ways yes, in some ways no. In the morning, we have the sunrise which can also produce beautiful colors. According to photographers, sunrise is cooler than sunset. No, not in terms of temperature, but in the colors displayed in the sky. Overnight, when the sky is cooler, fewer particles rise in the sky, giving the sun’s rays less stuff to refract off of. The result? Sunrises give off more bluish tones than sunsets.

 

So, which is more beautiful, a sunrise or a sunset? There’s no right answer to this one! Leave your thoughts below, in the comments.

 

Sleep in the Time Between Daylight and Darkness

Should you wake up at dawn? Should you go to bed at dusk? These are common questions when thinking about the sun rising and falling, as there are some rather romantic ideals about waking up with the sun, laboring hard, and falling asleep when the sun sets. Is it feasible, though?

 

You should not wake up with the sun, nor go to bed precisely after twilight. Not only is it not a realistic idea for modern humans, it never has been for any humans.

 

To follow the most natural sleep cycle, wake up at the coldest part of morning and go to bed three hours after dusk.

 

Even if you aren’t living in Newfoundland, which is so far North it has all “day” nighttime at parts of the year, the twilights come at different times each morning and evening. While these changes are not sporadic (except for when there is a time change due to Daylight Savings Time) they can vary by quite a lot over the course of the year. Even Singapore, which is relatively equatorial, has noticeable differences in twilight times through the seasons.

 

What should you do instead?

 

Research on the sleep habits of indigenous people has revealed to us what the most natural sleep pattern is most likely like. Waking up is done, not by the light of the sun, but at the coldest part of the night. Sleeping, on the other hand, does correlate with sundown… about three hours later. Note that this is still later than the average bedtime of US adults.

 

Twilight in Popular Culture

Due to the deep symbology of twilight as a barrier between light and dark, night and day, and the known and the unknown, it is often referenced in popular culture. Here are some (infamous and) famous twilight references in popular culture:

 

• The Twilight Saga book series and movie series rocked teen girls’ collective minds in the aughts’. As the series concerns vampires, who cannot withstand the light of the sun, twilight is a key time of day for them. Seen in puzzle and riddle clues referencing the time between daylight and darkness for blood drinkers.
• The Twilight Zone TV series was an old black-and-white show that told short, one-off stories of the strange and bizarre.
• Board game lovers will know of Twilight Imperium, an infamously long game. Maybe it is called Twilight Imperium because its gameplay can start at one twilight and not end until the next. 😉
• My Little Pony has a character named Twilight Sparkle. Fun fact: She was originally going to be called Twilight Twinkle.
• The Legend of Zelda video game, Twilight Princess. It features the mysterious twilight realm, a place with limited light that is home to “shadow beings” called Twili.
• The Elliot Smith song Twilight features lyrics that include a sad person going to bed during the morning twilight to avoid the daytime.

 

All in all, the twilight hours keep us entertained, mystified, and curious. What are your favorite references to twilight in culture, life, and art? Let us know in the comments below!