Question about Phases of the Moon. Thanks

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    Moon Phases Thanks
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Discussion Overview

The discussion revolves around understanding the phases of the Moon as viewed from space, specifically how to represent the illuminated and shaded portions of the Moon's surface in a diagram based on its position in orbit around the Earth. Participants are addressing a specific lab exercise involving shading the Moon's surface for various positions (A - E) as seen from above the North Pole.

Discussion Character

  • Homework-related
  • Debate/contested
  • Exploratory

Main Points Raised

  • One participant presents a problem involving shading the Moon's surface for different positions, seeking confirmation of their attempt.
  • Another participant questions whether "shaded" means illuminated or dark, emphasizing that only the side facing the sun is lit.
  • Some participants express confusion about the relationship between the Moon's phases and the shading required, with one suggesting they are incorrectly interpreting the task.
  • Clarifications are made regarding the illuminated side of the Moon, with a participant stating that the left half would be dark at position D, corresponding to a new moon phase.
  • There is a discussion about the Waxing Crescent phase, with participants attempting to identify the correct shading based on the Moon's position as viewed from space.
  • One participant asserts that half of the Moon's surface is always illuminated, reiterating that the shading must reflect this regardless of the observer's position on Earth.
  • A participant shares a diagram to confirm their understanding of the illuminated portion, which is acknowledged as correct by others.
  • Further discussion leads to eliminating certain positions based on the amount of light visible, with a focus on identifying the correct lunar phase corresponding to the diagram presented.

Areas of Agreement / Disagreement

Participants express varying interpretations of how to shade the Moon's surface based on its phases and positions. There is no consensus on the initial attempts, but some agreement emerges regarding the understanding that half of the Moon is always illuminated. The discussion remains unresolved regarding the exact shading for each position.

Contextual Notes

Participants display uncertainty about the definitions of shading in relation to illumination and the phases of the Moon. The discussion reflects a dependence on visual representations and interpretations of lunar phases, which may not be fully resolved within the thread.

nukeman
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Ok, here is the problem I have:

Figure 2 shows the Moon in its orbit about the Earth, as viewed from space high above the
North Pole. Copy the figure into your lab book and for each position A − E shade the appropriate
portion of the Moon’s surface as viewed from space, NOT as viewed from Earth.

here is the image:
http://i51.tinypic.com/2coo1lz.jpg

Here is my attempt:
1hwmq8.jpg



Am I correct?
 
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Doesn't look right. Is shaded supposed to mean illuminated or dark?

Only half of the moon's surface is illuminated at any given time -- the half that faces towards the sun.
 
Then I am doing it wrong, I thought I would have to shade it based on moon phases like waxing cresent and what not.


Any maybe shade one of them, point me in the right direction?

Thanks!
 
You didn't answer my question. In your attempt, is shaded supposed to mean lit or dark?

As I said before, the side that faces towards the sun is lit (obviously). For example, at position D, the right half of the moon would be lit. The left half would be dark, because it faces away from the sun. Since the left half is the half that faces towards Earth, this position happens to correspond to a new moon phase.

EDIT: Well, new moon would be somewhere between D and E, when they're all completely aligned.
 
Last edited:
Ahhhh. I see.

So, just so I make I got this right, let's take E

Its in Wax Cresent correct?

So, the small sliver of moon showing, would be on the right side ?
 
nukeman said:
Ahhhh. I see.

So, just so I make I got this right, let's take E

Its in Wax Cresent correct?

So, the small sliver of moon showing, would be on the right side ?

The question asks for the shading as seen from space, NOT as viewed from the Earth. What would the Moon look like looking down from a distance high above the North pole?
 
nukeman said:
Ahhhh. I see.

No, you don't.

cepheid said:
Only half of the moon's surface is illuminated at any given time -- the half that faces towards the sun.

cepheid said:
As I said before, the [half] that faces towards the sun is lit



nukeman said:
So, just so I make I got this right, let's take E

Its in Wax Cresent correct?

So, the small sliver of moon showing, would be on the right side ?

No! That is how it would appear from EARTH, but that's only because observers on Earth cannot see all of the illuminated side from their vantage point. That doesn't change the fact that there is always an illuminated side -- one entire half of the surface is always lit, which means that at every single one of the positions shown, you will have half of the surface shaded and half not shaded.
 
Right, so half moon is always lit.

So then, the following diagram is correct?

http://i55.tinypic.com/bj5t20.jpg

Note: the dotted part of the moon is the lit portion.
 
anyone? :)

nukeman said:
Right, so half moon is always lit.

So then, the following diagram is correct?

http://i55.tinypic.com/bj5t20.jpg

Note: the dotted part of the moon is the lit portion.
 
  • #10
nukeman said:
Right, so half moon is always lit.

So then, the following diagram is correct?

http://i55.tinypic.com/bj5t20.jpg

Note: the dotted part of the moon is the lit portion.

That is correct.
But, for future reference, the common notation is to shade in the... erm... shade. :)
 
  • #11
nukeman said:
Right, so half moon is always lit.

So then, the following diagram is correct?

http://i55.tinypic.com/bj5t20.jpg

Note: the dotted part of the moon is the lit portion.

Now, that is correct, which of the Moon positions A − E best corresponds to the lunar phase shown?
 
  • #12
Well, you can eliminate a, b, and c, because they are either mostly lit, or half lit, and this picture is clearly mostly dark.

So, it's between E and D. Which position would allow you to see a sliver of light on the left part of the moon?
 
  • #13
Archosaur said:
Well, you can eliminate a, b, and c, because they are either mostly lit, or half lit, and this picture is clearly mostly dark.

So, it's between E and D. Which position would allow you to see a sliver of light on the left part of the moon?

Is it wanning crescent?
 
  • #14
Yes.
 

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