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Eleni_
Hello all, as i write in the title my question is about the colour of the moon. Yesterday evening, i saw the moon rising to the sky in a red colour. Why is this happening? Is it an atmosphere/ gas problem?
thanks a lot for your anwer. So normally, the colour we should be looking at should be red but it gets filtred by the atmosphere and we see it white? I mean normally the moon is grey. We are able to see it because it is lightened by sun. The reflection of the sun by the moon which is not filtred makes the early moon seems red? Does hat low explains the waves as well?Charles Link said:I do think we may have been close to a lunar eclipse the other night, with the solar eclipse coming up in another week an a half. I saw the very reddish moon also. Normally as the moon rises, instead of being white, it appears somewhat orange as the light passes through about 100 miles of atmosphere before it reaches us when the moon is on the horizon and the blue light gets scattered out. (Overhead, the atmospheric layer is about 10 miles, and that encircles the Earth which is a sphere of radius 4000 miles, so that as the moon rises, it may have 100 or more miles of atmosphere to pass through to reach us). The blue light and shorter wavelengths gets scattered much more than the longer wavelengths such as orange and red, so we see the orange and red that reaches us directly. In this latest instance, I think that some of the light reaching the moon may have traveled through the Earth's atmosphere before reflecting off the moon, so that the blue light and other shorter wavelengths got filtered out much more than usual, where normally the Earth's atmosphere isn't in-between the path of the light from sun to the moon. ## \\ ## When the moon is overhead, the light only has 10 miles of atmosphere to pass through, so that most of the blue light, (and violet and green and all of the other colors), from the moon makes it directly to us along with the orange and red and the moon appears white in color. ## \\ ## Incidentally, this atmospheric scattering that scatters the shorter wavelengths much more than the longer wavelengths is known as Rayleigh scattering, and this also explains why the daytime sky appears blue. Most of the scattered light is light of shorter wavelengths. It also explains why the sun appears red or orange during a sunrise or sunset.
No, it's the other way around. It would look white if there were no atmosphere. (or rather white-ish, since it's sun's white light reflected off of dirty grey surface)Eleni_ said:So normally, the colour we should be looking at should be red but it gets filtred by the atmosphere and we see it white?
Yes, perhaps that is why I observed it to be more red on the horizon than usual, rather than an effect such as a near lunar eclipse. Since the atmospheric layer isn't more than about 20 miles, a near lunar eclipse should not produce the effect that was observed. I observed it to be reddish looking east from Chicago, but perhaps the smoke from the west traveled far eastward.BillTre said:Two days ago I saw the moon at about 30-40 degrees above the horizon.
It was a strong orange, more so than I have noticed recently.
Where I live (Eugene, Oregon) and we have recently had a lot of smoke in the area due to forest in Canada (and other places), I assumed the color of the moon was due to the smoke in the air doing the filtering.
Local conditions might also have an effect.
I think i got it now! You guys are amazing thanks :)Bandersnatch said:No, it's the other way around. It would look white if there were no atmosphere. (or rather white-ish, since it's sun's white light reflected off of dirty grey surface)
The following is mostly just rehashing Charles' answers, but maybe it'll click if put in different words:
What you saw is what happens when light coming from some source is being scattered by gasses or particulates in the atmosphere. This scattering is most efficient with shorter wavelengths, meaning that colours from the blue end of the spectrum are removed from the light, and what gets through is the longer wavelengths, on the red end of the spectrum.
The more gasses and particulates are there in the way, the more scattering occurs. This means that you're most likely to see yellowish or even reddish moon when it's just above the horizon, where there's the most atmosphere for the light to get through. You're also more likely to observe red moons in polluted air.
Think of it in terms of RGB colours. Red+Green+Blue netts white. Scattering removes first blue (turning the source yellowish), then green (looks reddish), then red (it's completely obscured by the thick haze in the atmosphere).
This is the same mechanism that makes rising/setting sun look red, yellowish most of the time, and nearly white when it's approaching the zenith (because that's where there's the least atmosphere to scatter its light).
The Moon appears red due to a phenomenon called "lunar eclipse". During a lunar eclipse, the Earth comes between the Sun and the Moon, casting a shadow on the Moon. The Earth's atmosphere filters out most of the blue light, leaving only red light to reach the Moon's surface, making it appear red.
No, the Moon can appear different shades of red, from a light orange to a dark red, depending on how much dust and clouds are present in the Earth's atmosphere during the eclipse.
A lunar eclipse can occur twice a year, but not all lunar eclipses are total eclipses where the Moon appears completely red. It depends on the alignment of the Sun, Earth, and Moon.
Yes, the Moon can also appear red during a "blood moon" or "supermoon". A blood moon occurs when there is a total lunar eclipse at the same time as a supermoon, which is when the Moon is at its closest point to Earth in its orbit.
No, the Moon is not physically changing color. The red appearance is simply a result of the Earth's atmosphere filtering out certain wavelengths of light during a lunar eclipse.