Moonshine

[Chesterton]

Possible stupid question alert, but why does the moon shine so bright? The astronauts say when they were on it the moon looked dull dark grey, kind of like pavement. But from here it's very bright and luminous. I assume if the moon were were to start moving towards Earth it would gradually appear duller and duller, but why is that exactly?

And the only time I've seen a planet up close through a good, powerful telescope I saw Saturn. Through the telescope it wasn't shiny, illuminated obviously but not brilliantly shiny as planets are to the naked eye.

 

[Shemjaza]

Possible stupid question alert, but why does the moon shine so bright? The astronauts say when they were on it the moon looked dull dark grey, kind of like pavement. But from here it's very bright and luminous. I assume if the moon were were to start moving towards Earth it would gradually appear duller and duller, but why is that exactly?

And the only time I've seen a planet up close through a good, powerful telescope I saw Saturn. Through the telescope it wasn't shiny, illuminated obviously but not brilliantly shiny as planets are to the naked eye.

I think it's because the Moon is in a vacuum so there isn't haze and atmosphere to absorb light like distant things on the Earth, so if it's further away the reflected light is more bunched together and it looks brighter, where as if you are nearby you can see all the dark bits between the light bits.

 

[SkyWriting]

Possible stupid question alert, but why does the moon shine so bright? The astronauts say when they were on it the moon looked dull dark grey, kind of like pavement. But from here it's very bright and luminous. I assume if the moon were were to start moving towards Earth it would gradually appear duller and duller, but why is that exactly?

And the only time I've seen a planet up close through a good, powerful telescope I saw Saturn. Through the telescope it wasn't shiny, illuminated obviously but not brilliantly shiny as planets are to the naked eye.

It looks bright in comparison to space.
Grays are like that.
See how the astronaut is TIDE clean?

 

[Oafman]

It's not a stupid question. The amount of light the Moon reflects (its albedo) is actually rather low, in comparison to other solar system bodies.

The Moon has an average albedo of 0.12. This means it reflects 12% of the light that hits it. Jupiter and Saturn have much higher albedos - around 0.5 - and Venus is even higher at 0.65 (lots of light bounces off their thick atmospheres).

So why does the Moon appear so bright, with such a low albedo? Because it's very close to us!

 

[[serious]]

Possible stupid question alert, but why does the moon shine so bright? The astronauts say when they were on it the moon looked dull dark grey, kind of like pavement. But from here it's very bright and luminous. I assume if the moon were were to start moving towards Earth it would gradually appear duller and duller, but why is that exactly?

And the only time I've seen a planet up close through a good, powerful telescope I saw Saturn. Through the telescope it wasn't shiny, illuminated obviously but not brilliantly shiny as planets are to the naked eye.

Likely the same reason the center bar appears to have a gradient (it's a solid color):

 

[Loudmouth]

Possible stupid question alert, but why does the moon shine so bright? The astronauts say when they were on it the moon looked dull dark grey, kind of like pavement. But from here it's very bright and luminous. I assume if the moon were were to start moving towards Earth it would gradually appear duller and duller, but why is that exactly?

As others have pointed out, it is bright compared to space. If you see the Moon during the day, it isn't that bright.

And the only time I've seen a planet up close through a good, powerful telescope I saw Saturn. Through the telescope it wasn't shiny, illuminated obviously but not brilliantly shiny as planets are to the naked eye.

You are seeing less and less light with more and more magnification. You are effectively spreading light over a larger area, making the concentration of light go down. The same effect can be seen when using a microscope. A comfortable light setting at the highest magnification will be way too bright at the lowest magnification, and even brighter when using your naked eye.

 

[florida2]

When asked in an honest spirit of learning, there is no such thing as a stupid question.

 

[timewerx]

Possible stupid question alert, but why does the moon shine so bright? The astronauts say when they were on it the moon looked dull dark grey, kind of like pavement. But from here it's very bright and luminous. I assume if the moon were were to start moving towards Earth it would gradually appear duller and duller, but why is that exactly?

Because your eye's pupils are more dilated in the dark and when they are dilated more, they accept more light which is why the moon appears brighter.

But if you saw the moon during the day, the moon looks rather dull, like a tiny cloud because your eyes are a lot less dilated so the moon appears a lot less bright.

And the only time I've seen a planet up close through a good, powerful telescope I saw Saturn. Through the telescope it wasn't shiny, illuminated obviously but not brilliantly shiny as planets are to the naked eye.

This mostly has to do with the telescope's optics. I made my own telescopes as a kid using projector lenses. Higher magnification settings gives a dimmer image - the only way to rectify this is simply give the telescope a bigger diameter lens.

You can make a small telescope using a small lens with insane magnification but the image would be quite dim and the resolution would be poor - this is why telescopes with very high magnification tends to have large diameter lenses or mirror like in observatories so the image is bright enough and the resolution is adequate.

 

[Chesterton]

As others have pointed out, it is bright compared to space. If you see the Moon during the day, it isn't that bright.

That seems to be the consensus. Then why wouldn't you get the same effect by shining a flashlight on an object in a pitch black room?

 

[[serious]]

That seems to be the consensus. Then why wouldn't you get the same effect by shining a flashlight on an object in a pitch black room?

You do. Shine that same flashlight on something Backlot and you will see the same effect.

 

[Justatruthseeker]

Possible stupid question alert, but why does the moon shine so bright? The astronauts say when they were on it the moon looked dull dark grey, kind of like pavement. But from here it's very bright and luminous. I assume if the moon were were to start moving towards Earth it would gradually appear duller and duller, but why is that exactly?

And the only time I've seen a planet up close through a good, powerful telescope I saw Saturn. Through the telescope it wasn't shiny, illuminated obviously but not brilliantly shiny as planets are to the naked eye.

First off, the only stupid question is the one that goes unasked.

Although the moon has a low albedo - it's reflective index - it is fairly close, so most of the light that it does reflect reaches you. If you took a dark grey circle and place it on a black background, it will appear brighter than it would be compared to a white background as well.

This is also why Pluto can not be distinguished by spectroscopy from the background stars. Only by its movement against them is it able to be distinguished as a planet and not a star.

Also the moon has crystalline structures in the dust. Even if you shine a light on a pure black crystal, you will see bright reflections where the crystalline structure reflects the light. Unlike the diamond in the picture below, the moon is not flat across a large portion, but is like the angled surfaces you see reflecting the light.

 

[Chesterton]

You do. Shine that same flashlight on something Backlot and you will see the same effect.

Are you sure about that? I'm not going to go to the trouble of conducting the experiment in my house, but I really can't imagine I'd shine a light on a clump of grey dirt and it would shine like the moon.

 

[morse86]

Possible stupid question alert, but why does the moon shine so bright? The astronauts say when they were on it the moon looked dull dark grey, kind of like pavement. But from here it's very bright and luminous. I assume if the moon were were to start moving towards Earth it would gradually appear duller and duller, but why is that exactly?

And the only time I've seen a planet up close through a good, powerful telescope I saw Saturn. Through the telescope it wasn't shiny, illuminated obviously but not brilliantly shiny as planets are to the naked eye.

Read your bible instead of depending on the foolish "philosophers" of this world. It clearly states in Genesis that there were lights and one of them were the lesser light: the sun and the moon.

No, the moon does not reflect off light. It emits it's own light.

 

[Chesterton]

Read your bible instead of depending on the foolish "philosophers" of this world. It clearly states in Genesis that there were lights and one of them were the lesser light: the sun and the moon.

No, the moon does not reflect off light. It emits it's own light.

Stating that "there is a light" does not imply that it emits its own light. For most purposes, light is light, whether it's reflected light or direct from the original source.

 

[morse86]

Stating that "there is a light" does not imply that it emits its own light. For most purposes, light is light, whether it's reflected light or direct from the original source.

Here is another test:
Go get a magnifying glass and put it under the moonlight and measure the temperature. Then measure it in the shade.

The temperature will be lower in the moonlight than in the shade......the moon emits it's own light, it's a cooling light.

 

[Chesterton]

Here is another test:
Go get a magnifying glass and put it under the moonlight and measure the temperature. Then measure it in the shade.

The temperature will be lower in the moonlight than in the shade......the moon emits it's own light, it's a cooling light.

What's a cooling light?

 

[Shemjaza]

Here is another test:
Go get a magnifying glass and put it under the moonlight and measure the temperature. Then measure it in the shade.

The temperature will be lower in the moonlight than in the shade......the moon emits it's own light, it's a cooling light.

this isn't true.

 

[Loudmouth]

Are you sure about that? I'm not going to go to the trouble of conducting the experiment in my house, but I really can't imagine I'd shine a light on a clump of grey dirt and it would shine like the moon.

You would have to use something with the same light output as the Sun, and use a reflector that takes up the same surface area as the Moon does. Of course, this should all scale to the appropriate light intensities and surface areas for the distances involved. You would also have to block stray light coming from your light so that the only light you see is what is reflected back to you.

 

[Chesterton]

You would have to use something with the same light output as the Sun, and use a reflector that takes up the same surface area as the Moon does. Of course, this should all scale to the appropriate light intensities and surface areas for the distances involved.

You need big light and big surface area. So moonshine is just one of those "big" things, comparable to how mass warps spacetime, but only when the mass is relatively great by human terms, and otherwise the effect is negligible?

You would also have to block stray light coming from your light so that the only light you see is what is reflected back to you.

I don't know about that, because there's really a lot of light traveling through space from where we sit. While looking for information on this, I was reminded that on a moonless night, a bright Venus gives enough light to cast shadows on Earth.

 

[Green Sun]

There really are no such things as dumb question when it comes to Outer Space and Astronomy. These sort of questions are very important! There's no shame in not knowing and wanting to learn more!

As said by others, it comes down to it's size (relatively) extreme closeness to Earth.

While it's albedo is low, it's large and close to us, and the Sun is very bright. So even if it only reflects a tenth or so of the light, it's still sending a lot of light back at us. Since there's no other objects as close to Earth with even close to a similar size, the Moon simply overpowers the light from stars, planets, etc, similar to what the Sun does during the day.