by Ann » Sat Aug 08, 2015 6:02 am
Chris Peterson wrote:MarkBour wrote:So, if we remove the Earth from behind the Moon, it looks brighter, and perhaps this is how the Moon "really looks" in the void of space from a spacecraft. But it still doesn't seem nearly bright enough. Why doesn't it look this way to us on Earth? The Moon on a dark night looks quite radiant and white when high in the sky. Is this image at a lower brightness setting than what our eyes would have seen if we were sitting on DSCOVR?
Our eye/brain system creates its own white and dark levels which are context dependent. Not only brightness, but color adapts. The Moon looks bright white because our brains tell us that's what it is. It only looks less than white if we have a brighter reference object... which is seldom the case.
The Moon looks bright white because our brains tell us that it is? That is a strange explanation.
Unlike the Earth, which is multicolored - mostly white, dark blue and grayish-brown - the Moon is grayish-brown all over, about the same hue as dry earth soil. Some parts of the lunar surface are darker and others are brighter, but they are all more or less the same grayish-brown hue. Therefore, when we look at the Moon on a clear night when it is high in the sky, we don't see color. If we were looking at the Earth while standing on the Moon we
would see color, because the Earth is multicolored.
Yuri Gagarin, the first person in space, described the Earth
like this:
What beauty. I saw clouds and their light shadows on the distant dear earth.... The water looked like darkish, slightly gleaming spots.... When I watched the horizon, I saw the abrupt, contrasting transition from the earth's light-colored surface to the absolutely black sky. I enjoyed the rich color spectrum of the earth. It is surrounded by a light blue aureole that gradually darkens, becoming turquiose, dark blue, violet, and finally coal black.
But because the the monocolored Moon doesn't offer us any color sensations, we can only judge its brightness, not its hue. And the Moon looks overwhelmingly bright against the black night sky. The magnitude of the full Moon is -12.74. No other object in the night sky comes close to being that bright.
I would say that it is the overwhelming contrast between the illuminated lunar surface and the blackness of the space that makes the Moon look white to us. But since the Earth is brighter than the Moon, mostly because of highly reflective white clouds, the Moon would look "a darker shade of bright" and also probably a little reddish if we could see it in front of the bright multicolored and bluish disk of the Earth.
Ann
[quote="Chris Peterson"][quote="MarkBour"]So, if we remove the Earth from behind the Moon, it looks brighter, and perhaps this is how the Moon "really looks" in the void of space from a spacecraft. But it still doesn't seem nearly bright enough. Why doesn't it look this way to us on Earth? The Moon on a dark night looks quite radiant and white when high in the sky. Is this image at a lower brightness setting than what our eyes would have seen if we were sitting on DSCOVR?[/quote]
Our eye/brain system creates its own white and dark levels which are context dependent. Not only brightness, but color adapts. The Moon looks bright white because our brains tell us that's what it is. It only looks less than white if we have a brighter reference object... which is seldom the case.[/quote]
The Moon looks bright white because our brains tell us that it is? That is a strange explanation.
Unlike the Earth, which is multicolored - mostly white, dark blue and grayish-brown - the Moon is grayish-brown all over, about the same hue as dry earth soil. Some parts of the lunar surface are darker and others are brighter, but they are all more or less the same grayish-brown hue. Therefore, when we look at the Moon on a clear night when it is high in the sky, we don't see color. If we were looking at the Earth while standing on the Moon we [i]would[/i] see color, because the Earth is multicolored.
[quote][url=https://en.wikipedia.org/wiki/Yuri_Gagarin]Yuri Gagarin[/url], the first person in space, described the Earth [url=http://www.spacequotations.com/earth.html]like this[/url]:
What beauty. I saw clouds and their light shadows on the distant dear earth.... The water looked like darkish, slightly gleaming spots.... When I watched the horizon, I saw the abrupt, contrasting transition from the earth's light-colored surface to the absolutely black sky. I enjoyed the rich color spectrum of the earth. It is surrounded by a light blue aureole that gradually darkens, becoming turquiose, dark blue, violet, and finally coal black.[/quote]
But because the the monocolored Moon doesn't offer us any color sensations, we can only judge its brightness, not its hue. And the Moon looks overwhelmingly bright against the black night sky. The magnitude of the full Moon is -12.74. No other object in the night sky comes close to being that bright.
I would say that it is the overwhelming contrast between the illuminated lunar surface and the blackness of the space that makes the Moon look white to us. But since the Earth is brighter than the Moon, mostly because of highly reflective white clouds, the Moon would look "a darker shade of bright" and also probably a little reddish if we could see it in front of the bright multicolored and bluish disk of the Earth.
Ann