It was 4 AM on a Winter's Night.
Sunrise wouldn't be until for over another 3 hours at 7:17 AM. However, as I glanced out the front window, outside was as bright as daytime. Just a few minutes before, the night had been so black that you couldn't see anything in the dark. Then, suddenly, everything to the Northern horizon was aglow. Near the horizon, there was also a band of clear blue sky glimmering as colorful as a Summer's Day. How curious.

For several minutes (before I ever thought of grabbing a camera), I just stared out the window. I tried to understand where the light to the North (away from all light pollution) was coming from & why everything outside was so bright. It was bright enough that if your eyesight was good, it was bright enough to read... It was certainly bright enough to read street signs without any help. Most curious.

Truthfully, I never considered spaceships, aliens, or any sort of "other worldly" explanation for the bright sky. So, I guess my imagination isn't that great. I had also once before (10 years ago) seen a similar dark night turned into "like daytime" https://pbase.com/britestar/image/131996173. So, I just assumed there had to be some sort of natural explanation for what I was seeing. After all, a Solar Eclipse can make midday briefly seem like nighttime. Why couldn't some other natural phenomenon make night briefly look like daytime?

I studied the sky for a long time to convince myself that the light wasn't manmade, as in an unexplained searchlight. It was so very bright to the north. However, even as the northern bright light calmed down, I could still see everything outdoors (from the bushes close to our front door to the color of our neighbors' house over two blocks away) as clearly if it were a Winter's Day & not 4 AM without even a moon in the sky. I decided that this was definitely the result of something happening with Nature & NOT man (neither human nor little green ones) created.

As the brightness started to again dim, I finally thought to get a photo. You can see that photo above. The sky in my photo is much darker than when I first noticed the phenomenon, but you can still see that things certainly does not look like 4 AM. You can make out features on a neighbor's house over 6 acres away. And you can see the patch of blue light just below the low hanging cloud cover. Pretty cool.

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Later, when doing a quick search on the Web for why night can look like day, I came up with several articles that explain something called "Air Glow", including these: https://www.theguardian.com/science/2017/jun/28/bright-nights-scientists-explain & https://www.science.org/content/article/bright-night-glowing-sky-mystery-solved

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According to Wiki
"Airglow is caused by various processes in the upper atmosphere of Earth, such as the recombination of atoms which were photoionized by the Sun during the day, luminescence caused by cosmic rays striking the upper atmosphere, and chemiluminescence caused mainly by oxygen and nitrogen reacting with hydroxyl free radicals at heights of a few hundred kilometres.

"Airglow at night may be bright enough for a ground observer to notice and appears generally bluish. Although airglow emission is fairly uniform across the atmosphere, it appears brightest at about 10° above the observer's horizon, since the lower one looks, the greater the mass of atmosphere one is looking through. Very low down, however, atmospheric extinction reduces the apparent brightness of the airglow.

"One airglow mechanism is when an atom of nitrogen combines with an atom of oxygen to form a molecule of nitric oxide (NO). In the process, a photon is emitted. This photon may have any of several different wavelengths characteristic of nitric oxide molecules."

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Other explanations of Air Glow seem to get even more complicated and scientific, but put together, they provide a good explanation as to why a night sky can suddenly become unusually bright in the absence of a moon or made man lighting. In the case of the night sky in my photo, it also explains the band of daytime blue sky just above the horizon. Isn't Nature fascinating?

Spaceweather.com has said: Although airglow does not require solar activity, there is a strong link to the solar cycle. It also said, "Airglow is rarely seen from the ground, but it can become a more common sight in the coming months and years as solar activity ramps up."

The brightness was passing. In less than 20 minutes later, everything outside was once again pitch black. The photo was taken after the peak of brightness outdoors had dimmed. But you can see that -on a moonless night - it still doesn't look like normal nighttime. I wonder what things would have looked like without any cloud cover.

If I had better understood what I was seeing at the time, I would have used a long exposure to shoot my photos. And I would have started to shoot when the sky brightness was at its maximin. The colors of Air Glow is best captured with long exposure. Maybe next time, if there is a next time. Meanwhile, just witnessing this phenomenon twice now has been a treat.

My image from 2011 https://pbase.com/britestar/image/131996173 shows the brightness produced by Air Glow even more than the photo above. Amazed about how night had turned into "day", I never thought to look to the sky for colors either time. I merely took a memory photo each time "just because" something was beyond the ordinary. Interestingly, 2011 was a year of increasing solar activity; just like 2021.