Why does Sunset look different from Sunrise?

[gary350]

TL;DR Summary

WHY does Sun set look different than Sunrise?

WHY does Sun set look different than Sun rise?

 

[Vanadium 50]

Because it rises in the east and sets in the west.

 

[gneill]

Different how? I mean besides the background details (one is in the east, the other in the west, so different backdrops). What details are you interested in? Please be specific.

 

[PeterDonis]

Moderator's note: Thread level changed to "B".

 

[russ_watters]

WHY does Sun set look different than Sun rise?

Since you didn't say how you think they look different and I've never noticed such a thing, I can only speculate as to what you mean or why: The weather at sunset is usually warmer than at sunrise and the relative humidity lower, wind stronger, clouds higher, atmosphere more turbulent, etc. These factors will affect the way sunset vs sunrise look, but they are not going to be consistent. They can be inverted.

 

[hmmm27]

I've never noticed but - if true - I suspect it may have to do with the amount of water vapour in the atmosphere : more in the evening, less in the morning.

 

[russ_watters]

...if true - I suspect it may have to do with the amount of water vapour in the atmosphere : more in the evening, less in the morning.

Kind of. Yes, there will generally be a little bit more absolute humidity in the evening, but not much. The relative humidity on the other hand is vastly different (lower in the evening), and that's what affects the transparency of the atmosphere.

 

[gneill]

In the (moderately) recent past the sunrise/sunset appearance differences were substantially influenced by daily industrial activity which introduced particulate matter into the air during daytime hours. It would largely settle/disperse overnight, hence different concentrations of particulates morning versus evening. Now of course such activity tends to be rather more 24/7.

Still need to know what you mean by "look different".

 

[anorlunda]

I've heard before that many people believe that sunsets do look different, but then people who get up early enough to see sunrises every day say, "No, on the average they look alike."

I have certainly seen spectacular sunrises where the whole sky turns red.

 

[256bits]

Local topography and prevailing weather patterns can play a part, just due to the amount of air the sunlight has to pass through in the morning or evening, and would have some effect upon the distribution of aerosols in the the air.
An old saying "Red sky at night, sailor's delight. Red sky in morning, sailor's warning." was actually a line of sight weather prediction of an approaching storm, or clear skies, which for a sailor you might want to know of rough seas ahead or wind for your sails. Latitude specific no doubt.

Since people per se are not reliable witnesses with their faulty memories and ingrained biases, comparisons do end up being more subjective than objective in a lot of cases. It might be a good opportunity for the OP to tabulate his viewings from one day to the next and season to season, and see if the assertion really stands up or not. That would be interesting.

 

[russ_watters]

An old saying "Red sky at night, sailor's delight. Red sky in morning, sailor's warning." was actually a line of sight weather prediction of an approaching storm, or clear skies, which for a sailor you might want to know of rough seas ahead or wind for your sails.

Well let's try to analyze that in the context of the OP.

The atmosphere scatters blue light and makes direct sunlight redder. But it isn't "red sun" it is "red sky", so what is needed is a low transparency of the sky to reflect the red light from the sun. So that means high relative humidity. Frankly it seems at first counter intuitive to me, since red sky in the morning should be a normal thing whereas red sky at night should mean very humid air and clouds/storms.

...but maybe someone has another interpretation?

 

[Baluncore]

With dawn, you are rested, your colour vision is refreshed and more sensitive to the colours of the dawn. The shadows have gone, you are awake, the world is bright and new, you are elated and active.

With dusk, your sun bleached colour vision is poor, the shadows rapidly lengthen and deepen as you are overcome by a dim monochrome world. You are depressed and ready for sleep. You light a candle to dispel the fear and give yourself hope.

 

[256bits]

Well let's try to analyze that in the context of the OP.

The atmosphere scatters blue light and makes direct sunlight redder. But it isn't "red sun" it is "red sky", so what is needed is a low transparency of the sky to reflect the red light from the sun. So that means high relative humidity. Frankly it seems at first counter intuitive to me, since red sky in the morning should be a normal thing whereas red sky at night should mean very humid air and clouds/storms.

...but maybe someone has another interpretation?

It would matter if weather comes from the east or west. No.
Maybe it's backwards for the westerlies in mid latitude area for normal days of rain and shine.

But don't cyclones and hurricanes come from the east, so a red sky would mean a violent storm approaching, where these types of situations occur.
So most likely the rhyme is for the tradewinds nearer the equator that travel east to west, rather than for the westerlies.
If moisture laden air is to the west the storm has past your area. If red to the east in the morning, a storm may be approaching.

 

[Baluncore]

https://www.loc.gov/everyday-myster...warning-true-or-is-it-just-an-old-wives-tale/
(Matthew XVI: 2-3,) Jesus said, “When in evening, ye say, it will be fair weather: For the sky is red. And in the morning, it will be foul weather today; for the sky is red and lowering.”

 

[PeterDonis]

It would matter if weather comes from the east or west.

Yes, it does. Note that the traditional morning = warning, night = delight version is for sailors. Sailing ships typically preferred the trade wind latitudes, as you note, where the prevailing wind is easterly, so the weather comes to you from the east.

don't cyclones and hurricanes come from the east

They generally travel westward in the tropical latitudes, but typically recurve back eastward as they move to higher latitudes.

 

[256bits]

They generally travel westward in the tropical latitudes, but typically recurve back eastward as they move to higher latitudes.

Quite right.
The southern west coast of NA doesn't ( usually ) storms coming in from sea for that reason.

 

[PeroK]

Summary:: WHY does Sun set look different than Sunrise?

WHY does Sun set look different than Sun rise?

There is material online about this. E.g.:

https://knowledgenuts.com/2015/11/27/is-this-a-sunrise-or-a-sunset/

https://www.livescience.com/34065-sunrise-sunset.html

 

[gary350]

Look at sun set every evening it is 90% red light. Look at early morning sun set not much red light. I read atmosphere on horizon makes red light but why not early morning? Sun is about 8 minutes ahead of what we actually see. Morning sun is already up 8 minutes above horizon before we actually see it. Evening sun is 8 minutes below horizon and we still see it. I wonder if angle of light is doing something similar like rainbow does refaction makes all other color light be gone on horizon so we only see red. Maybe color is effected by weather, all the USA weather comes from west to east. Sun may look different to everyone according to where you live. Weather on west coast comes down from Alaska then moves east. If your standing on the west coast beach looking east you may see more clouds in that direction than someone standing on the east coast beach. MIT physics lecture says, sky is blue because angle of refraction elimites all colors of light except blue so we see blue. When I am out on west coast traveling and camping in big sky country I see the difference between sun rise & sun set.

 

[PeroK]

Look at sun set every evening it is 90% red light. Look at early morning sun set not much red light. I read atmosphere on horizon makes red light but why not early morning? Sun is about 8 minutes ahead of what we actually see. Morning sun is already up 8 minutes above horizon before we actually see it. Evening sun is 8 minutes below horizon and we still see it. I wonder if angle of light is doing something simular like rainbow does refractor makes all other color light be gone on horizon so we only see red.

You see the Sun where it was when it emitted the light. Where it is when that light arrives is irrelevant. In general, the motion of a source of light after the light has been emitted cannot affect the previously emitted light.

Your premise that sunsets and sunrises are fundamentally different is, according to the evidence, false.

 

[Motore]

I never saw a difference in redness of the horizon between the sunrise or sunset.

@gary350 which one of the photos below represents sunset and which one sunrise?

 

[anorlunda]

I hope this is not too off-topic. It is related.

My experience standing watch at sea is that the moon illusion, is more noticeable at moonrise than at moonset. The illusion is that the Moon appears to be larger when near the horizon.

But I also have a human psychology theory for the asymmetry. Moonrises at sea are startling, and thus memorable. Unlike sunrise, moonrise is not preceded by a glow in the sky giving advance warning. As you scan the horizon, all of a sudden a big red light appears. Your heart skips a beat as you fear getting run over by a huge vessel. It takes 5 seconds for the brain to analyze and conclude that it is the moon. That moment of fear makes the memory strong. My wife and I found that no matter how many times it happened before, we were still surprised and startled by the next moonrise.

But moonset is uneventful and forgettable, so you tend to stare at it less and you miss seeing the moon illusion.

So my theory is just that we scrutinize and remember moonrises more than moonsets. It is a self-created illusion. That is similar to what I said in #9 about sunrise/sunset.

Edit: I should have mentioned that this applies only when the moon rises at night.

 

[gary350]

I hope this is not too off-topic. It is related.

My experience standing watch at sea is that the moon illusion, is more noticeable at moonrise than at moonset. The illusion is that the Moon appears to be larger when near the horizon.

But I also have a human psychology theory for the asymmetry. Moonrises at sea are startling, and thus memorable. Unlike sunrise, moonrise is not preceded by a glow in the sky giving advance warning. As you scan the horizon, all of a sudden a big red light appears. Your heart skips a beat as you fear getting run over by a huge vessel. It takes 5 seconds for the brain to analyze and conclude that it is the moon. That moment of fear makes the memory strong. My wife and I found that no matter how many times it happened before, we were still surprised and startled by the next moonrise.

But moonset is uneventful and forgettable, so you tend to stare at it less and you miss seeing the moon illusion.

So my theory is just that we scrutinize and remember moonrises more than moonsets. It is a self-created illusion. That is similar to what I said in #9 about sunrise/sunset.

Edit: I should have mentioned that this applies only when the moon rises at night.

Most people go crazy over a red sun set but that is like comparing a dark gray over cast rainy day to a nice sunny day. I like nice bright morning sun rise much better than dark red sun set.

Sunset is actually a red color rainbow when sunlight is at 42 degree angle to our eyes.

 

[sophiecentaur]

There are many more clear tinted sunrises than clear sunsets where we live (East of London, with Essex and the North Sea to our East. Sunrises can have a lovely crisp redness but the dust and clouds from the West produce a very different (no less impressive) orange colour, with all sorts of purples and blues in the clouds. I wonder what it would have looked like before the clear air act came in. (Cue JMW Turner and Claude Monet)
Sunrise flatters to deceive, here. For instance, I woke up to a clear sky thinking "Now for some decent Sun Imaging." Since about 10.00 it has been cloudy and I never saw any distinct sunset. That's about par for the course.

 

[sophiecentaur]

Sunset is actually a red color rainbow when sunlight is at 42 degree angle to our eyes.

But rainbows are seen when the Sun is behind you. Red sky is caused by scattering and not by refraction.