Question about the apparent colour of planets

[The Singing Badger]

Hi Celestians,

Here's a stupid question that has been bugging me this week. Maybe someone can help me out with it. It all started when I was using Celestia is a planetarium and noted that the colouring of the Moon in Celestia does not reflect what it actually looks like to the human eye.

We all know that the Moon is dark grey in colouring. When we see photos of astronauts on the Moon, the landscape is dark grey.

Yet when we look at the Moon from Earth, it shines bright white.

Presumably if one were looking at the Moon from a spaceship orbiting the Earth, the Moon would still appear to be bright white, right?

So here's my question: at what point in one's journey toward the Moon does it cease to appear bright white, and begin to appear grey? It looks grey in photos from Apollo orbiters, but do those photos represent what the human eye would see?

I realise this is pretty elementary stuff but I am poorly educated and would be interested in any theories.

I have a related question that is bugging me even more, but I'll ask that later...

[tony873004]

When you look at the Moon in the night sky from Earth, your eyes are adjusted to dark, and the moon is very bright compared to the darkness of nightime. So it appears overexposed to you and hence whiter that it really is. If you look at the moon in the daytime sky, it looks greyer, but its contrast is washed out by the bright sky.

If you have a digital camera, put it in manual mode. In the day, take a picture of a dark object that is in full sunlight. Adjust your settings so the picture is properly exposed. Next time the Moon is in the night sky, use those same settings to take a picture of it. It'll probably look something like this:

[The Singing Badger]

OK, so apparent colour is subjective depending on the background. That makes sense.

But ... imagine you're Neil Armstrong on the moon. You're looking at the lunar landscape and the dark lunar sky. Is the landscape shining bright white compared to the sky? Or does it look grey? My guess would be grey - but why is that? What's the difference between looking at the Moon from a difference and looking at it close up?

Forgive my ignorance but I'm very intrigued!

[tony873004]

On Earth, the dark sky is huge and the Moon is small. Even though it looks bright, it is only 1/2 degree wide while the sky is 180 degrees wide. So not much light from the moon lands on your eyes. Your eyes adapt for the dark sky. If you carry a small mirror with you look at your eyes on a night with a full moon. Assuming there's enough light to see by, you'll notice that your pupils are huge. They are letting in a large amount of light. This helps you better see your surrounding on dark Earth, but it overexposes the moon.

If Neil Armstrong carried a mirror to the moon and he looked at his pupils, they would be small. They shrink down in an effort to properly expose his surroundings which are 180 of bright moon and 180 degrees of sky.

So he sees a gray moon.

Have you ever had the eye doctor put drop in your eyes to dialate your pupils so he could examine your eyes. And then for a few hours after your check-up you had to wear those cheap sunglasses they give you?

If Neil Armstrong brought drops to dialate his pupils, the Moon would probably look bright white to him too.

[The Singing Badger]

Tony, you rock. Thanks for explaining this so simply and clearly. So, as Neil and friends travel to the Moon in Apollo, it gets greyer and greyer as it starts to fill their field of view, and their eyes increasingly adjust to the Moon rather than the dark sky...?

Thanks again. Now I can get some sleep.