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Why is the sky red at night?

Discussion in 'Science and Nature' started by bkadoctaj, Apr 11, 2009.

  1. Some nights in the city/suburbs the sky is red at night? Some nights with clouds it's red, other times it's not. What's the deal?
     
  2. #2 Jankydank, Apr 11, 2009
    Last edited by a moderator: Apr 11, 2009
    Pollution?

    Or something to do with how high or low the sun is or refraction when light passes through the atmosphere.
     
  3. So pollution Saturday, clean sky Sunday?

    And how do you imagine this turns the sky red?

    I'm not talking about sunset. I'm talking 3 AM, like right now. Some nights it's black.
     
  4. #6 Jankydank, Apr 11, 2009
    Last edited by a moderator: Apr 11, 2009
    How did you miss the first paragraph? The moisture in the air changes how the light passes through the sky I guess.
     
  5. It's particles in the air, be that pollution or moisture, that catches light from the city at night. It is red, because the red part of the spectrum have a longer wavelenght. The shorter wavelengths are absorbed by the dense layer of particles, so only the longer wavelengths are reflected.

    For the same reason sunsets and sunrise are red. The suns light must travel through more atmosphere to reach the viewer, so more of the shorter wavelengths (the blues and greens) are absorbed by the atmosphere, and the longer ones (red) pass through.
     
  6. #8 Medicine Al, Apr 11, 2009
    Last edited by a moderator: Apr 11, 2009
    To help poor new wave musicians get new cars?:D
    [ame=http://www.youtube.com/watch?v=-gYBvSx_wCA]YouTube - The Fixx - Red Skies[/ame]

    I dig the bearded bass player in the cape.
     
  7. I guess the light explanation does make sense. It just seems like the sky shouldn't be naturally red at midnight.
     
  8. Well, if it weren't for the massive amount of artificial light any city radiates, it wouldn't happen. So no, it isn't natural :)
     

  9. Yeah, but some nights it's not there. To me, it being there sometimes and not others is what is artificial about it.
     
  10. it being there at all is artificial

    it wasnt there 200 years ago, I promise you.
     
  11. Well, again, it depends upon the density of particles over the city, whether those be pollutants or moisture.

    If it is say a sunday to monday night with not much traffic, there won't be many exhaust fumes, will there? And if it is a dry night to boot, not much moisture particles either.

    It do not matter what particles it is, as long as they are there in enough density to reflect the light given off from the city.

    Around here, that means "low hanging clouds" on good nights, and traffic smog on non-windy bad nights, as my city is trapped by mountains on three sides, and ocean on another. Which essentially traps just about everything as a lid over our city center. As such, red-sky is more normal than not. Not to mention rain.

    But the cool thing is looking at it from above, when one go up to one of the mountains surrounding the city, and look down :)

    (When I say go, I really mean drive... I haven't got the stamina to trek up hills ffs :p )
     
  12. im going to amend my post, without editing, but only because I got baked and I can see someone pointing this out

    I said it didnt happen 200 yrs ago, and prior. Well, I cant verify that, but I can logically assume it to be false.

    Consider a volcanic eruption. the amount of ash and gases released into the air should be a sufficient source of pollution as to cause the red glow. There are probably tons of natural forms of pollution that would suffice...

    but yeah, it didnt happen *much* prior to the industrial revolution
     
  13. pollution aka shit for our lungs and the earth
     

  14. What on earth... it has been around since the beginning. There has always been dust, pollution and water in the atmosphere. Just because of our pollution its more distinguishable.
     
  15. It is light pollution reflecting off clouds. No clouds, it doesn´t happen.
     
  16. It's the same where I'm at too, but I live in a flat area. Also, clouds don't seem to have anything to do with it. Sometimes there is complete cloud cover, but the sky looks natural, but other times it is red. I would buy the whole idea behind traffic if I didn't know that not many people drive hear at all, regardless of the day
     
  17. where i live when its like that at night it means its going to snow and it always does or did
     
  18. electron radiation/heat transfer.. i think
     
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