Is this scheme the proper explanation of why the upper part of the moon is illuminated ?

Here’s a scheme made by one of reddit users to explain why the upper left part of the moon is illuminated even though the sun is visibly lower above the horizon than the moon.


Concerns this video:

This not my video, ignore what the guy is saying, just watch the relation between the way the moon is illuminated and where the sun is.

Please justify your viewpoint.

How about you justify *your *viewpoint?

Your diagram is two dimensional.

Whereas in reality, the sun and moon are not flat discs in the same plane perpendicular to the observer’s line of sight. I’d imagine that makes quite a difference.

I agree. What do you think about this scheme ? It was made by another guy to explain the same problem I stated in the first post of this thread.

This thread promises not to be baffling at all.

WHAT problem, karol? Can you just state in simple words what the problem is that you’re attempting to find a solution to here? In plain English?

In the video, the portion of the moon that is illuminated is the portion from the half of it that is facing the sun.

More or less as expected. :slight_smile:

Do you have a question or a debate?

The sun should be visibly higher above the horizon to illuminate the moon like this. Do you agree with the scheme presented in the first post ? Is this the explanation ?

karol is a believer in the idea that the Earth is hollow and that we live on the inside. He’s been posting various threads attempting to disprove heliocentrism, all failing to do so of course. I expect this is another such attempt.

I think the sun is right where it should be to illuminate the moon as it does. I don’t agree with the diagram in the OP, though; It shows the angle between the sun and moon (relative to the observer) as much too small. In the video, it shows the sun, then swings well around to show the moon. I would say the sun is about 45° above the horizon in the west, and the moon about the same angle in the east. (Or the directions could be reversed, depending if it’s morning or afternoon.) I don’t have a diagram to back it up, but there’s nothing mysterious about it.

Well, I think you need to look closer then.

Karol, why don’t you ask Phil Plait or Neil deGrasse Tyson about this, or aren’t they privileged to have the special knowledge you have? Are they part of the world-wide conspiracy that only you have been able to penetrate?

Ok, maybe this will make you more productive. It should at least.

How are you doing with contacting Phil Plait or Neil deGrasse Tyson? How about the Miami Planetarium?

And would you please answer my question in post #50 of your previous thread on this subject?

From that link:

Now, that there is some good science!


There is some ignorance to be fought here.
This is the photo in question that needs to be explained;
note that the phase of the Moon is pointing upwards, while the Sun is low in the sky.

This is a real effect, not Photoshop, and I have noticed it myself. How can this be - the Moon is facing upwards, while the Sun is lower down?

The answer is - both Sun and Moon lie upon the same Great Circle in the sky. The sky can be modelled as a sphere at an arbitrary distance from the observer, and the shortest distance between the Sun and Moon is a Great Circle that passes through both objects. Any light that travels from the Sun to illuminate the Moon will pass along that Great Circle, and it is easily possible for the Great Circle that passes through the Moon to appear to be tilted upwards as seen by an observer on the ground.

Another indication that the image above is not reliable if you want to draw straight lines to indicate light paths is that the road in the lower part of the picture is almost certainly straight- but it appears very curved in that image.

Here is a thread over at Bad Astronomy/Cosmoquest explaining this illusion- warning it is 958 posts long.

Because he’s too good for us now and doesn’t post here anymore. Yeah, there are other ways to ask him, but I hold a grudge.

Yeah, I was aware of all that. I was hoping against hope that this time, he might deign to actually state a claim of some sort.

My viewpoint is that every single photo you’ve posted demonstrates a perfectly well understood optical phenomenon, or a common photographic effect. And you claim that these photos somehow are not what we say they are, but you have yet to respond with any explanation beyond “no it’s not - watch my video!”

And adding diagrams like in the OP, that are demonstrably inaccurate, doesn’t help your case.

Here’s a photo of the Milky Way. Please explain to us how, in your world view, I could go out and actually see it form an arch like that in the sky.

There’s a model of the solar system I use that has never let me down. In it the Sun is the center of the Solar System and lies about 93 million miles away from the Earth. The moon revolves around the Earth and lies a little less than 250,000 miles away. The sun illuminates both the Earth and the Moon because they’re both spheres. Give me a date and time and a location on Earth and I can draw what the moon will look like in space just based on the math that was built using the model above.

Sometimes the moon might look weird but this is because a) the distances are much greater than what our minds want to think when we just look at the objects in the sky and b) you maybe don’t have the right perspective of where the moon is and incorrectly interpret what part of the moon is lit. For example, you think it’s lit from the side when in actuality it’s lit more from the front.

Karol’s view of the universe if foolhardy, not backed by observation (other than his own), and he’s incapable of intelligently arguing his point of view. That’s hardly surprising given that the model the OP subscribes to is incoherent.

It’s the same reason why the shortest path between the US and Europe passes further north than either of the endpoints. Maps and photographs are flat, but the Earth and the sky are spherical.