Before the days of science, people believe that the moon emits light. When astronauts traveled to the moon they testified that the moon does not emit light.

Scientist came up with the idea the moon is merely reflecting the light from the sun. Can anyone tell me which silly goat came up with this idea?

The theory contradicts itself and yet we can accept it. If the moon reflects light then it would had been seen as emitting light. Shine a torch into your eyes and it would be too much light for you. Even if this light is reflected into your eyes by a mirror it has the same effect.

I am also surprise astronauts accepted this theory. They had approached the moon and saw that it was lightless. It was not like approaching a mirror with a light beam shinning on it. What I cannot understand is as you approach the moon you can see that it does not emit any light. Here on the surface of earth you can see moon light. Those who are good in science please enlighten me. Thanks.

This post has been edited by faceless: Jan 17 2011, 03:15 PM

Dunno, I don't care who he is

It's not a theory, it's what was observed, long before a man sets his foot on the moon. That's why anybody with a telescope can see the moon's
surface but can't observe the sun directly.

Can't really make heads or tails with these statement, sorry...

You betcha

Get a hold of a telescope, you'll see...
Not me, but Wiki might shed a clue...

Modern mirrors would probably reflect >95% of the light. How sure are you the surface of the moon reflects that same amount?

The atmosphere and effects of general relativity(though it maybe too small to have significant effect, just guessing on this one) would definitely impact the way we see light from the moon at night.

You are wrong, in every paragraph.

I do not need to travel to the moon to see that it does not emit light. I can see the moon pretty well, right here on earth. I don't even need a telescope, which already existed for many hundreds of years before the first astronaut reached the moon.

How do you know that the moon does not emit light and instead only reflects that from the sun? Look at the phases of the moon. And it's relative position to the sun during these phases.

If you had a telescope, or just really good eyes, when the moon is in the right position, the dark parts are illuminated by light reflected from the earth and is not completely dark. It should be even more obvious then.

PS: I just had a thought. Please look up the word "reflect" in a dictionary. It is not only mirrors that reflect light. Perhaps this is the source of the confusing post.

Have u ever try looking at the light from your torchlight through the mirror and compare to when you look at it with your eyes? Its the same. If the moon emits light, then it shud be very bright, but its now only a dim light

Perhaps TS was under the mistaken impression that "reflect" is what mirrors does, like when you can see your own reflection in a mirror. Light bouncing off (and scattering off) other objects like walls, trees, etc; he does not classify under the term "reflect".

If this is true, then this is not a science question at all, but merely a confusion as to the meaning of a single English word.

I don't quite understand what is the issue here. Emitting and reflecting is 2 different issue to start with.

Emitting light - mean the light source come from the moon

Reflecting - you see the object, because there source of light that shine on it. Without it, you don't see the object at all.

Hmm, after reading some of the replies here I think what TS meant by this statement:
"Shine a torch into your eyes and it would be too much light for you. Even if this light is reflected into your eyes by a mirror it has the same effect."
is that if we say that the moon 'reflects' the light of the sun like a mirror then, there should be no difference between 'moonlight' and 'sunlight', so the confusion really is on how the word reflect is used in English and science/physics

p/s some facts:
Reflectivity -according to science the moon's reflectivity is about the same as a coal's
Emmisivity

p/p/s Before reading the topic I thought it was about how moonlight gives rise to legends of the werewolf

Thanks Befitozi and Dkk for the explanation of the word "reflect" from a science perspective. Mgjg your links on reflectivity and emissivity had been helpful. I am still not clear on this subject. I think the intensity of the light from the moon is very high to be visible on earth. The light from a two battery torch light is of no comparison. It had made me wonder why astronauts were not glared by the moonlight.

http://en.wikipedia.org/wiki/Albedo

albedo of moon around 0.12 which is about that of asphalt
albedo of snow around 0.9

Have you ever shone light on your body and see how many % was reflected? There will be some, but it will be very dim.

Thanks Slimey,
As I understand from the link, albedo is measure from 0 to 1. The closer to 1 to more reflective the object is. It had lead me to conclude that the lower the albedo the less reflective the object is when you are close to it. As in the case of the moon. When we are near it, we dont even see it reflecting the sunlight. On earth, a great distance away, it had reflect the sun light very well. Moon light can illuminate the night so there is no total darkness at night. It does so for half the globe regardless of full moon or half moon.

If my conclusion correct?

This post has been edited by faceless: Jan 19 2011, 03:08 PM

Albedo has nothing to do with distance, it's just a measure of the reflectiveness of an object. The more reflective it is, the brighter it appears when reflecting light. Distance will reduce the amount of light coming from a bright object due to the way light spreads out as it travel.

You can only see the moon only when it is reflecting light from the sun. It is possible to for the moon to be in the sky and not seen during a new moon when the shadow side of the moon is facing the earth.

The moon's albedo is 0.12. The earth's albedo is 0.3. If you think the moon seems bright from here, the earth looks even brighter when you're standing on the moon.

Add to that the fact that the earth is much larger, it throws a lot more reflected sunlight on to the moon, than the other way around.

The moon only seems so bright because the sky around it is dark. Actually it's not all that bright. I can think of two ways to demonstrate this.

1) Find a street light near your house. Walk around until you see the moon in the sky near where the light appears to you. You would see that the light is much much brighter than the moon

2) Look into a torch light while you are in a dark room at night. The torch light seems very bright. Wait 12 hours until the sun is up. Go out. Turn on the torch light and look at it again. It would seem very dim.

nice analogies....

ya....it's about perception and relativity.....

another point to add.
during the dark, the pupils of the eye dilate to allow more light to enter the retina, which will give you the perception that it is brighter than it actually is.

Almost everything reflects light. A white t-shirt reflects white colour to you, that's why it is white. A green one absorbed all other colours but reflected green colour. Does a white t-shirt blind your eyes? No, it doesn't. Same case for the moon.

Okay, moonlight is not bright. It still does not explain moonlight ability to illuminate the night. Have you experience night of total darkness. I had camp out in the wild often and I never experience total darkness.

It explains how strong sunlight really is.

If that is the case Mgjg, then there is no night. We had so many stars out there.

Stars are millions of light years away, by the time the light source reaches Earth, they've been scattered far apart. Chances are the 'star' you see at night are not the main bodies of the star, but the intense glare from the light emitted from it, that's how strong starlight/sunlight actually are.

Natural visible light scatter the further it is from the source unless you focus and amplifies it like in a laser, and even laser isn't immune to scattering by atomic imperfection of vacuum/space.

By the time sunlight bounces off the moon and hitting earth, it's scattered so much that it's barely illuminating the night and it's not heating up the atmosphere anymore, or rather, the heat is dissipated by our atmosphere faster than moonlight can heat it up.

This post has been edited by SeaGates: Jan 21 2011, 02:09 PM