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Shouldn’t the Moon appear as bright as a full Moon seen at midnight from Earth? The photo was taken by DSCOVR at Lagrange point 1. In the picture, The Moon appears dark gray. Of course the Earth

Why does the Moon appear gray when passing between the Sun and the Earth? - Astronomy Stack Exchange body,.s-topbar{margin-top:1.9em} Stack Exchange Network Stack Exchange network consists of 181 Q&A communities including Stack Overflow, the largest, most trusted online community for developers to learn, share their knowledge, and build their careers. Visit Stack Exchange Loading… Tour Start here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more about Stack Overflow the company Business Learn more about our products current community Astronomy help chat Astronomy Meta your communities Sign up or log in to customize your list. more stack exchange communities company blog Log in Sign up Astronomy Stack Exchange is a question and answer site for astronomers and astrophysicists. It only takes a minute to sign up. Sign up to join this community Anybody can ask a question Anybody can answer The best answers are voted up and rise to the top Astronomy Home Public Questions Tags Users Unanswered Teams Stack Overflow for Teams – Start collaborating and sharing organizational knowledge. Create a free Team Why Teams? Teams Create free Team Teams Q&A for work Connect and share knowledge within a single location that is structured and easy to search. Learn more about Teams Why does the Moon appear gray when passing between the Sun and the Earth? Ask Question Asked 6 years, 5 months ago Modified 6 years, 4 months ago Viewed 4k times This question shows research effort; it is useful and clear 37 This question does not show any research effort; it is unclear or not useful Save this question. Show activity on this post. Shouldn't the Moon appear as bright as a full Moon seen at midnight from Earth? The photo was taken by DSCOVR at Lagrange point 1. In the picture, The Moon appears dark gray. Of course the Earth appears bright, reflecting sunlight from clouds and water. The Moon's surface is gray and should reflect less light than the Earth. It should be irrelevant that we see the far side, since the reflectivity of the Moon's surface should be the same on the far side as the side that faces the Earth. The midnight full Moon appears much, much brighter as seen from Earth than it does in this picture, despite the fact that the amount of sunlight reflecting from the surface of the Moon is the same in both instances. I understand the photo was taken with 3 separate exposures of red, blue and green, but this should not affect the brightness. So why does it appear so dull? the-moonearthlightsatellite ShareShare a link to this question Copy linkCC BY-SA 3.0 Improve this question Follow Follow this question to receive notifications edited Jul 26, 2016 at 15:32 Brian Leeming asked Jul 26, 2016 at 12:38 Brian LeemingBrian Leeming 48144 silver badges88 bronze badges 3 4 Actually the far side is a bit brighter than the near side. (Far and near being relative to the Earth.) So it does make a small difference. – Theodore Norvell Jul 26, 2016 at 14:16 8 At night you compare the moon to the blackness of space right next to it. So it seems to be white. But the moon's albedo (0.14) is only slightly higher than worn asphalt (0.12), so it is actually dark grey. Compare Earth (albedo 0.30) - much brighter. The picture doesn't seem over- oder underesposed, either - a miniature Earth and Moon wook look just like that in broad daylight (well, in front of a screen of vantablack) – Chieron Jul 26, 2016 at 14:24 This answer mentions the moon, issues of albedo, and is somewhat "what the moon really looks like" - related. – uhoh Jul 29, 2016 at 23:50 Add a comment  |  4 Answers 4 Sorted by: Reset to default Highest score (default) Date modified (newest first) Date created (oldest first) This answer is useful 42 This answer is not useful Save this answer. Show activity on this post. That's what it really would look like if you were there with DSCOVR. The albedo of the Moon is only about 0.136, about half of the Earth's average albedo. Of course the part with clouds is higher. I was shocked too, but it was explained in written copy that accompanied the release of the original image. Shouldn't the Moon appear as bright as a full Moon seen at midnight from Earth? It does. If the moon were a diffuse, white ball, a full moon would be about seven times brighter! If you watch the image or GIF, the Moon is roughly the same brightness as central Australia or the Sahara region. Phil Plait explains well in Bad Astronomy. There's a lot to read here. EDIT: I just ran across these images of astronauts on the surface while reading this answer. Their suits are not 100% white to begin with, but the Lunar soil - at least in these locations - is significantly darker. It is close to the same color as the (presumably) nearly-black radiator fins for the heat sink of the RTG unit (2nd photo) at the astronaut's foot. above: "Buzz Aldrin carries the EASEP." from here above: "Astronaut Alan L. Bean from Apollo 12, put the Plutonium 238Pu Fuel from the Lunar Module into the SNAP 27 RTG" from here. above: Image from NASA/NOAA from Bad Astronomy ShareShare a link to this answer Copy linkCC BY-SA 3.0 Improve this answer Follow Follow this answer to receive notifications edited Apr 13, 2017 at 12:58 CommunityBot 1 answered Jul 26, 2016 at 13:18 uhohuhoh 30.1k77 gold badges7676 silver badges241241 bronze badges 4 10 To give some perspective, 0.14 is about the albedo of aged asphalt pavement. The moon is actually pretty dark. – Tristan Jul 26, 2016 at 15:11 3 If you live near a planetarium or other museum that has a moon rock on display (I'm lucky enough to have worked at one), and have seen a moon rock up close, you'll note that the moon rock is dark grey with light specks throughout (at least the sample I've seen was). So it's no surprise that the entire moon is quite dark. – Benjam Jul 26, 2016 at 17:29 So this means the perception of a full moon as a bright white disk is just our human adjustment for the lack of other light sources? If the same full moon had a second earth passing behind it at a similar relative diameter, the view we'd perceive would be similar to that photographed above? – Will Jan 20, 2022 at 18:16 1 @Will I'm not an expert, but yes; if there was something Earth-like (or even a giant, diffuse white pingpong ball) somewhere near the Moon it would have a surface brightness way brighter than the Moon's! If you had to choose a crayon to draw the moon on white paper you'd have to choose a dark gray, and then add just a slight amount of brown or red to it. The photo of the astronaut with the dark gray soil on their suit is the reality. I was quite surprised when I researched and wrote this answer as well. – uhoh Jan 20, 2022 at 21:32 Add a comment  |  This answer is useful 11 This answer is not useful Save this answer. Show activity on this post. I think the confusion comes down to what "brightness" means. In general we don't really measure (either with our eyes or our cameras) the absoloute brightness of objects. Instead we measure the brightness relative to other objects in the scene. In the photo of the earth and the moon taken from between the earth and the sun the moon looks dark grey because the sunlit earth is brighter than the sunlit moon. In the night sky the moon looks white because it's bright compared to the night sky and the nighttime earth (even with some artificial lighting the nighttime earth is not lit up to anything like daytimes levels.. ShareShare a link to this answer Copy linkCC BY-SA 3.0 Improve this answer Follow Follow this answer to receive notifications edited Jul 26, 2016 at 18:45 answered Jul 26, 2016 at 15:46 Peter GreenPeter Green 24011 silver badge55 bronze badges 0 Add a comment  |  This answer is useful 9 This answer is not useful Save this answer. Show activity on this post. The other answers have pretty well covered the fact that the moon is made of dark gray stone. But I wanted to mention a way that you can verify this on your own with nothing more sophisticated than a camera with a manual exposure mode. Photographers have a rule of thumb called "sunny 16". This was much more important back in the day when cameras didn't have sophisticated light meters and on-board computers. Basically, the rule says that in direct sunlight, if you set your aperture to f/16, the correct shutter speed will be the reciprocal of your film speed. The moon is a sunlit object, and the sunny 16 rule exposes sunlit objects so they look the way we normally perceive them in sunlight. But if you apply the sunny 16 rule to the moon, it looks dark gray -- its "true" color and brightness as we would perceive it against a sunlit background of average terrestrial brightness. ShareShare a link to this answer Copy linkCC BY-SA 3.0 Improve this answer Follow Follow this answer to receive notifications answered Jul 27, 2016 at 4:41 Kevin KrumwiedeKevin Krumwiede 19122 bronze badges 3 See also en.wikipedia.org/wiki/Sunny_16_rule and en.wikipedia.org/wiki/Looney_11_rule – Brian Leeming Jul 27, 2016 at 11:50 Ha! I remember that! I remember ASA 64 film too. f/16 was popular on some old cameras that couldn't be focused to provide DOF. I just use my phone these days - do modern cameras allow you to somehow electronically emulate an ASA? Or does this have to be done with real film? – uhoh Jul 29, 2016 at 12:58 Modern DSLRs allow you to set the sensor sensitivity (the digital equivalent of film speed) and they at least nominally use the same units that film speed did (reffered to as "ISO"). I dunnno how accurate the calibration of those values is though. – Peter Green Aug 29, 2016 at 21:13 Add a comment  |  This answer is useful 3 This answer is not useful Save this answer. Show activity on this post. Because if the photograph were taken with an exposure setting that made the moon appear shiny and bright white, the Earth is so much more bright that it would completely wash out the scene. There is no way to objectively measure "brightness" of objects in a photograph without knowing how the image was captured. ShareShare a link to this answer Copy linkCC BY-SA 3.0 Improve this answer Follow Follow this answer to receive notifications answered Jul 27, 2016 at 17:39 Lightness Races in OrbitLightness Races in Orbit 20711 silver badge88 bronze badges 2 So the photobomb picture has an exposure setting that matches the earth in the background and not the moon? – Brian Leeming Jul 29, 2016 at 15:04 @BrianLeeming: For some value of "matches", basically yes. – Lightness Races in Orbit Jul 29, 2016 at 16:24 Add a comment  |  You must log in to answer this question. Not the answer you're looking for? Browse other questions tagged the-moonearthlightsatellite. Featured on Meta Navigation and UI research starting soon Should we at least temporarily ban chatbot-generated content (e.g. chatGPT)... 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