Visible Observations of the moon

[LunarMartian101]

Hi.

I am an avid astrologer and love using my telescope to observe the moon.

I've noticed over my life time there is only ever one visible face of the moon no matter where you look from on our planet.

This is easily verifiable by anyone with a telescope.

How does DET account for this phenomenon?

[JRowe]

There is only one visible face under DET too; only one face gives off light, so only that face even could be seen.

Also, astrologer or astronomer?

[badxtoss]

Feb 5, 2018 19:20:45 GMT JRowe said:

There is only one visible face under DET too; only one face gives off light, so only that face even could be seen.

Also, astrologer or astronomer?

We only see one face but it isn't always lit. How does that work in det?

[JRowe]

This is explained in the overview; it is basically a rotating spotlight. As time goes by, the unlit sides/back rotate into view and in doing so cut off the lit face. When viewed from the side you just get the light that peers around, forming a crescent, for example. When viewed from the back, it's a new moon.

[badxtoss]

But that isn't what we see, if I am understanding you. We see the same face, pretty much the same angle all the time
It's just the lighting that changes. you can actually watch the shadow creep over observable features over the course of a few days.

[JRowe]

It's an optical illusion, and one you can easily create for yourself. Take any flat surface, like the face of the moon. Say, a piece of paper. If you mark a dot on the right hand side and rotate that paper, moving the dot further away, that dot will continue to be visible on the right hand side. Ditto for the left.

[badxtoss]

But, again, that isn't what we see. We see that familiar shape slowly be covered by a shadow. Just look at the moon, better still photograph it over the course of a month and you will see what I am talking about.
Another thing is that it doesn't change shape over the course of the night. If it were close, it would wouldn't it?

[JRowe]

I have looked at many such photo compilations, there are a number of notable changes in focus and intensity over the course of a month. If you look for specific landmarks, certainly you will find them, but otherwise details do appear to change.
How could it change shape? The light of the moon is not a reflection, it is the specific shape of a lit face that is visible. That isn't going to change over the course of a day.

[badxtoss]

Focus or brightness may change but that's not really relevant. What you are looking for is those landmarks and how they are gradually covered by shadow. So, you're right, we always see the same face, but that face isn't always lit.
As for shape, that's easy. Take frisbee, or plate, and hold it over your head. It is round. Now move it away from you and it will appear to, A: shrink, and B: change shape to more and more of an ellipse.
If the moon is as close as a few thousand miles, or closer, it would appear to do the same thing as it moved away from you over the course of the night.

[JRowe]

Landmarks are unreliable, because you'll see them no matter the angle, all that'll change is the angle with which you see them. For example, a spire-like imperfection would appear like a dot head-on, and a line when angled to the side, and the darker spots certainly appear longer the more the moon's rotated.

The distance to the moon doesn't alter especially, though the reason why is a little in-depth, how much of the overview have you read? If you understand how the Sun shines on each disc, it's basically an extension of that, but I need to know how much you know before I know how much to explain.

[badxtoss]

Feb 6, 2018 13:51:22 GMT JRowe said:

Landmarks are unreliable, because you'll see them no matter the angle, all that'll change is the angle with which you see them. For example, a spire-like imperfection would appear like a dot head-on, and a line when angled to the side, and the darker spots certainly appear longer the more the moon's rotated.

The distance to the moon doesn't alter especially, though the reason why is a little in-depth, how much of the overview have you read? If you understand how the Sun shines on each disc, it's basically an extension of that, but I need to know how much you know before I know how much to explain.

But they don't change. This is readily explained by a large moon very far away. And the fact that the light and shadows do change is readily explained by its light being reflected from the sun which is also very far away. I'm confused how DET explains this.
I have read your overview but to be fair it has been a while.

[JRowe]

There's a certain amount of confirmation bias at play. If you look for similarities you will find them, for the reasons previously gone through, but there is no denying that there are also changes.

Compare, for example:



There are features to the right of the full moon that are just not visible on a crescent, and many of the marks and features don't appear particularly similar. You could view this as a result of light from a different angle, but what gives that priority?

And that's fine, I don't expect anyone to have total knowledge of the overview. So long as you've read it, you likely have a vague idea of the underlying framework of DET. If anything I say is unclear, referring back might help, most of this area is covered in section 3.
The distance to the moon doesn't particularly alter. The light from the moon takes a particular route to us; outwards, crossing a fraction of the radius of the Earth, and then it appears at a point in the sky, from which the light travels down. There are two components to that journey; if it were only the latter component you would be right, the moon would appear to change in size. The rotation of the moon about the centre of the whirlpool it's in (and the subsequent movement of its image) it what causes the journey of the moon through the sky, however. Essentially, that aspect of the journey of the moon's light compensates for the other. There is a slight fluctuation but it's very minor.