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The moon is bright, and if you were 50 times closer it would be 25 degrees across with the same surface brightness, which would be pretty dazzling. Looking at the moon through a telescope (which increases the apparent size, but can't increase the apparent surface brightness) can certainly be dazzling. So looking at a 25 degree circle of a surface reflecting sunlight at 150 million km from the sun can be dazzling.

But, in the words of Pink Floyd "There is no dark side of the moon really, matter of fact it's all dark." The moon has an albedo of 0.12, about the same as dark soil. So looking at a 25 degree circle of dark soil here on Earth (also 150 million km from the sun) should be just as dazzling as looking at the moon if we were 50 times closer to it. But dark soil looks dark. Why the difference?

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  • $\begingroup$ The dust on the Moon is really fine (& of course extremely dry), so visually comparing it to dark Earth soil is a little misleading. A better comparison is with the surface of a (bitumen-paved) road. $\endgroup$
    – PM 2Ring
    Dec 27, 2019 at 15:48

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Did you try to look at a dark soil circle when everything around you (and around the circle) is dark? It will be quite dazzling.

Meaning, you perceive brightness as a relative quantity so the same amount of light will look dim or glaring depending on your environment. For example, did you look at a high beam of a car during the night and during the day? At night, when your pupils are large you will be totally glared. But at daylight, it won't matter much because your pupils are small due to all of the surrounding lights.

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  • $\begingroup$ Not only the pupil dilation plays a role: light adaptation by bleaching is of the greatest importance here. $\endgroup$
    – Ruslan
    Dec 27, 2019 at 15:59
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Look at the candle lit in the sunny day. Look at the same candle during night. The ‘brightness’ of a candle does not change, yet it is quite easy to predict, in which scenario it will be more easy to spot. The similar argument applies to moon as it is surrounded mostly by a dark background.

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