Is it possible to perceive a difference between sunrise and sunset?

Pendant (n).
One who,
by correcting others,
gives himself (or herself)
just enough rope
by which to hang.

Me, 1993

Having been a ‘pendant’ (by the above definition) for many years, I’ve gotten into the habit of questioning my own preconceptions about yIn ‘u’ Hoch je (Life, the Universe, and Everything). Colour me pretentious, but I actually believe that this is a Good Thing, especially in this (anti-)social media dominated era, where misinformation and disinformation foster bad memes and ‘FAKE NEWS!!!!1’. Being constantly on guard for the possibility that one’s view of reality could be wrong is, surely, a useful attitude. Training an open mind is, I believe, the route to wisdom.

‘Sunray Meadow’ by @lacharpenta
Used with permission (click to embiggen)

So when my friend Goldie, in response to last week’s wibblette, adamantly asserted that @lacharpenta’s photo, above, was definitely taken in the morning, not the evening, I wondered how he could be so certain. I began to doubt my own belief that it was impossible to determine whether the Sun in this photo was rising or setting. So, I decided to DuckDuckGo the question ‘Is there any difference in sunlight between morning and evening?‘.

The results were very interesting. I learned about Rayleigh scattering, Mie scattering and the Tyndall effect – but only a little: most of it went straight over my head (if you’ll pardon the pun).

One of the persuasive arguments I discovered was that human activity during the day kicks up pollutants into the atmosphere, so that, come evening, the Sun’s light is scattered more. This atmospheric dirt settles overnight, so the morning and evening skies can appear different.

And one thing I found particularly fascinating was that we can perceive a difference because of how our eyes work.

I was, however, unable to come up with a definitive answer.

Here’s an extract from one article this search revealed:

According to atmospheric physicists David Lynch and William Livingston, the answer is “yes, and no.”

All “twilight phenomena” are symmetric on opposite sides of midnight, and occur in reverse order between sunset and sunrise, the authors note in “Color and Light in Nature” (Cambridge University Press, 2001). That means there’s no inherent, natural cause of a major optical difference between them. However, two human factors break their symmetry.

The first is in our heads. “At sunset, our eyes are daylight adapted and may even be a bit weary from the day’s toil,” Lynch and Livingston write. “As the light fades, we cannot adapt as fast as the sky darkens. Some hues may be lost or perceived in a manner peculiar to sunset. At sunrise, however, the night’s darkness has left us with very acute night vision and every faint, minor change in the sky’s color is evident.” In short, you may perceive more colors at dawn than at dusk. [Red-Green & Blue-Yellow: The Stunning Colors You Can’t See]

Human activities also drive a divergence between them. “At sunset the sky is full of pollutants and wind-borne particles,” the authors write. “During the night, winds die down, smog-producing urban activity eases and the atmosphere cleanses itself. The dawn is clearer than any other time of day.”

Do Sunrises Look Different from Sunsets?‘, Live Science, 2012

If there is a difference between the appearance of skies near dawn and dusk due to the increase of pollution in the air during the day (and I don’t doubt that), then, surely, this effect will be greater in urban areas, due to smog.

Couple that with the concept of ‘normality’: it’s a natural tendency to believe that what experience teaches each of us to expect (in all manner of things) is ‘normal’ for everyone else, too. So, if you live in an urban area, you’ll be used to this greater dawn/ dusk sky difference effect… and perhaps come to believe that this is the same everywhere, and for everyone. Although I grew up in ‘The Smoke’ (London), for the last two decades I’ve lived in a rural area, where there’s never any smog. As I write this, the Sun is going down, and the sky seems to me just as blue as it was this morning.

So, perhaps it’s unsurprising that Goldie should both consider that this particular photograph is ‘definitely’ a morning one and find it hard to understand why I can’t see that. He’s absolutely right that this photo was shot in the morning: I got that straight from the horse’s mouth.

But being right about this image doesn’t mean that it’s always possible to tell a rising Sun from a setting one in every case; there are too many variables. Thanks to Goldie, I’m now better prepared to guess this of a similar photo, but I hope that I will always refrain from stating my opinion with certainty.

The Goon Show: morning and evening greetings

About peNdantry

Phlyarologist (part-time) and pendant. Campaigner for action against anthropogenic global warming (AGW) and injustice in all its forms. Humanist, atheist, notoftenpist. Wannabe poet, writer and astronaut.
This entry was posted in ... wait, what?, perception and tagged , , , , , . Bookmark the permalink.

9 Responses to Is it possible to perceive a difference between sunrise and sunset?

  1. granny1947 says:

    So, it depends on the time of day.
    My thought?
    Does it matter?


    • peNdantry says:

      Um. I apologise for not having made my message more plain. I don’t think it’s just about the time of day. There are all sorts of things in play here; perception being an important one of them.


  2. It’s a pleasure to witness wise reflections such as yours. Thank you!

    Liked by 1 person

  3. pennross says:

    I used to work in the film industry and many night time scenes were shot at dawn and visa versa. The look is almost exactly the same and was called magic hour. A second too late or too early and it was no longer believable. Getting in three or four takes was pushing it. But when watching a film or a tv show I love trying to guess.

    Liked by 1 person

    • peNdantry says:

      Thank you for endorsing the idea that it’s hard to tell sunrise from sunset.

      It’s interesting that you should mention the film industry, as that Live Science article I quoted above ends with a quote from Neil Degrasse Tyson:

      When viewed from all latitudes north of the Tropic of Cancer (23.5 degrees north latitude), the sun always rises at an angle up and to the right, and sets and an angle down and to the right. That’s how you can spot a faked sunrise in a movie: it moves up and to the left. Filmmakers are not typically awake in the morning hours to film an actual sunrise, so they film a sunset instead, and then time-reverse it, thinking nobody will notice.

      Liked by 1 person

  4. This was a fun read. It definitely would have been different if I were wrong. I’m glad that I prompted you to research this and learn a few cool things.

    Sometimes I just know things from observation, but without science to back it up – like in this instance. Other times, I know because I’ve done my research. I appreciate the message behind this post – have an open mind. I endorse it. I welcome it. However, I find that sometimes you have to stick up for what you know, or those that guess will sell you on their misguided ideas. It doesn’t work if only one of the sides is open to debate/additional research. It takes two to tango (or so the saying goes).

    P.S. I think you already know that I can: (1) be very direct, (2) be yanking your chain, (3) appear to be serious when I’m not, and more. I hope you didn’t imagine me literally stepping up onto a box, straightening my bow tie, and then shouting at you while pointing my finger at you.

    Liked by 1 person

    • peNdantry says:

      Goldie, I’m so very glad that you haven’t taken umbrage. I was a little worried that you might have. I thank you most sincerely for reminding me of the importance of listening to the opinions of others and ‘tangoing’ with a view to improving understanding.

      You’re absolutely right that it all falls down if only one side is listening. I fear that that is why the world is heading to hell in a handbasket; there are far too many whose minds are set, and won’t consider the possibility that their perception of reality may be flawed.

      Liked by 1 person

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