why is the moon gray? |
why is the moon gray? |
Dec 11 2010, 02:55 PM
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#1
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Member Group: Members Posts: 204 Joined: 29-June 05 Member No.: 421 |
Really this applies to a lot of the solar system worlds, just the moon is the nearest and most visible. Why is it gray? I'm thinking there are two contributing possibilities :
(1) it looks gray because human vision is limited to distinguishing only a narrow range of the spectrum; if we could see a wider range of colors it wouldn't be so gray. (2) it really is gray, even well beyond the range of human vision. This is because it is made up of gray rock, which doesn't have interesting spectral features really at any part of the spectrum. My inner seven-year-old is begging to know "why". A bit of googling seems to indicate that (2) is more of a correct answer than (1) -- at least the only colorful images I can find seem to be forced false-color by some processing to give extreme exaggeration to tiny color differences. Is that right? Can anyone elaborate? |
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Dec 11 2010, 04:49 PM
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#2
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Senior Member Group: Moderator Posts: 2785 Joined: 10-November 06 From: Pasadena, CA Member No.: 1345 |
Here is a really cool site that discusses the spectral properties of lunar rocks and even lets you "mix" your own lunar rock spectrum!
http://ser.sese.asu.edu/SPECTRA/index.html -------------------- Some higher resolution images available at my photostream: http://www.flickr.com/photos/31678681@N07/
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Dec 11 2010, 06:31 PM
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#3
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Solar System Cartographer Group: Members Posts: 10151 Joined: 5-April 05 From: Canada Member No.: 227 |
Take a good close look at a gravel bar in a river bed, or a pebble beach, or similar kind of collection of rocks... now, I'm saying that based on the kind of mixed rock areas I'm most familiar with, but I realize that in some places you could look at those things and see only one kind of rock. But in many places, look at a large collection of little rocks and you'll see a wide variety of shades and colours. Red, yellow, white, black, greenish, brown and so on. But step back and the whole beach, or bar, the whole pile of little rocks, looks grey. It's a mixture. On the Moon there's less variation to begin with. There will be white minerals, black minerals, a few that are slightly different, and then maybe a few coloured glasses, a bit green or orange. But mix it all together and the effect will generally be just grey again.
Phil -------------------- ... because the Solar System ain't gonna map itself.
Also to be found posting similar content on https://mastodon.social/@PhilStooke Maps for download (free PD: https://upload.wikimedia.org/wikipedia/comm...Cartography.pdf NOTE: everything created by me which I post on UMSF is considered to be in the public domain (NOT CC, public domain) |
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Dec 11 2010, 06:46 PM
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#4
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Senior Member Group: Admin Posts: 4763 Joined: 15-March 05 From: Glendale, AZ Member No.: 197 |
A couple of years ago I asked Buzz about how it "looked" with respect to color and he said it was overall gray but to the human eye there was in fact more color variation at ground level when they were out walking around (which fits what Phil is saying). And of course we know that there are visibly green rocks in Mare Imbrium.
-------------------- If Occam had heard my theory, things would be very different now.
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Dec 11 2010, 10:15 PM
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#5
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Dublin Correspondent Group: Admin Posts: 1799 Joined: 28-March 05 From: Celbridge, Ireland Member No.: 220 |
If I remember correctly the moon has quite a brownish tinge with a lot of variety but most of the images we see are monochrome. Here's a link to some Galileo color images of the moon that demonstrate this. It is still pretty gray but I think Phil's comment explains that.
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Dec 12 2010, 02:44 AM
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#6
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Member Group: Members Posts: 796 Joined: 27-February 08 From: Heart of Europe Member No.: 4057 |
Moon looks grey, but colors can be enhanced.
Look here: http://foto.astronomy.cz/Moon_color.htm It's czech page, but images are international . When you want full size images, click on "Snímek 1024x1024 pix". -------------------- |
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Dec 13 2010, 02:31 PM
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#7
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Forum Contributor Group: Members Posts: 1372 Joined: 8-February 04 From: North East Florida, USA. Member No.: 11 |
Well if you look at a rainforest from the air it looks mostly boring old green.........
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