# No, the moon phase can't help find your soulmate on TikTok

#### Jan Steinman

Which side of the moon a person sees illuminated during moon phases depends on which side of Earth they are on. For example, that means that for two people born on opposite sides of the world, two first-quarter moons should be a match and two third-quarter moons should be a match.

I'm having a huge problem with this.

It seems to me that the subtended angle from a person on a line to the moon that is tangent to one side of the Earth, to another person on the opposite tangent would be too tiny to make any difference in the viewed phase at all — let alone fourteen day's worth of moon motion.

Or am I missing something really obvious?

#### Unclear Engineer

Huh???

"Here's another issue with the moon/soulmate technique: Which side of the moon a person sees illuminated during moon phases depends on which side of Earth they are on. For example, that means that for two people born on opposite sides of the world, two first-quarter moons should be a match and two third-quarter moons should be a match. "

Really - NO!!! The phases of the moon look the same to everybody on Earth. The only differences is at what time of day/night on the Earth a person views the Moon. Yes, a moon that is rising in the East will look like it is cupped upward (and to one side) and look like it is cupped downward (and to the other side) when looked at at moonsetin the West - to anybody who looks at it from the Earth.

The person who wrote this should be assigned to stand outside for a month and take photos of every moonrise and moonset, then write at retraction.

#### RobLea

Huh???

"Here's another issue with the moon/soulmate technique: Which side of the moon a person sees illuminated during moon phases depends on which side of Earth they are on. For example, that means that for two people born on opposite sides of the world, two first-quarter moons should be a match and two third-quarter moons should be a match. "

Really - NO!!! The phases of the moon look the same to everybody on Earth. The only differences is at what time of day/night on the Earth a person views the Moon. Yes, a moon that is rising in the East will look like it is cupped upward (and to one side) and look like it is cupped downward (and to the other side) when looked at moonsetin the West - to anybody who looks at it from the Earth.

The person who wrote this should be assigned to stand outside for a month and take photos of every moonrise and moonset, then write at retraction.

I should have been clearer Unclear Engineer! By the other side of Earth, I'm referring to the northern and southern hemispheres. Obviously, during the first and last quarter moon phases, observers in different hemispheres see different sides of the lunar face illuminated as the illumination proceeds from different sides during the lunar month.

So for the first quarter moon, northern hemisphere watchers see the right side illuminated, and southern hemisphere watchers, see the left side illuminated! I could have added that near the equator the moon's bottom half or top half is illuminated so that's another difference!

You can check this on Tuesday,when the moon is at third quarter, Snap a pic in the northern hemisphere and get a pal in the southern hemisphere to do the same. You'll see opposite sides of the moon illuminated.

As for sitting out and photographing the moon phases, I'm up for it. My only conditions, a warm coat and a ticket to New Zealand to catch the moon phases from the southern hemisphere next winter!

Best,

Rob

#### RobLea

Hey Jan,

Check out my explanation to Unclear Engineer below. Should have specified different sides means Northern and Southern Hemisphere... Totally my bad.

Best,

Rob

#### Unclear Engineer

I see your problem: You are verbally equating changes in the viewers' perspectives as differences in "the side of the Moon".

A more realistic statement is that: People viewing the Moon from the Earth's South Pole see the same view of the Moon as people viewing it from Earth's North Pole, but each would interpret the other's view as "upside down", because the viewers themselves have defined "down" as 180 degrees different.

So, photographs taken by those two viewers and rotated by how ever many degrees are needed to make both "downs" coincide with the local "down" anywhere would appear to show opposite orientations of the same side of the Moon, thus appearing to make a complete circle in the combined photo that matches the local horizantals instead of the moom images. Of course, that would be obvious if the pictures had any detail of the actual Moon surface.

A similar argument can be made for two observers on different sides of the Earth at the Equator, but only if one is taking the picture at local moonrise and the other at local moon set. If they both do it at their local rise or set times, the pictures will have the same orientation of the illuminated cusps of the Moon image with respect to their local horizons.

But, I guess that you are thinking the confusing wording is OK content for an article about a mumbo-jumbo subject. The problem with that here is that this particular venue is supposed to be as firmly based on actual science as we can make it. Yes, the people who believe in the mumbo jumbo subject would speak like the article's text, but the purpose of the article seemed to be to put that into a more science-astronomy perspective.

#### RobLea

I see your problem: You are verbally equating changes in the viewers' perspectives as differences in "the side of the Moon".

A more realistic statement is that: People viewing the Moon from the Earth's South Pole see the same view of the Moon as people viewing it from Earth's North Pole, but each would interpret the other's view as "upside down", because the viewers themselves have defined "down" as 180 degrees different.

So, photographs taken by those two viewers and rotated by how ever many degrees are needed to make both "downs" coincide with the local "down" anywhere would appear to show opposite orientations of the same side of the Moon, thus appearing to make a complete circle in the combined photo that matches the local horizantals instead of the moom images. Of course, that would be obvious if the pictures had any detail of the actual Moon surface.

A similar argument can be made for two observers on different sides of the Earth at the Equator, but only if one is taking the picture at local moonrise and the other at local moon set. If they both do it at their local rise or set times, the pictures will have the same orientation of the illuminated cusps of the Moon image with respect to their local horizons.

But, I guess that you are thinking the confusing wording is OK content for an article about a mumbo-jumbo subject. The problem with that here is that this particular venue is supposed to be as firmly based on actual science as we can make it. Yes, the people who believe in the mumbo jumbo subject would speak like the article's text, but the purpose of the article seemed to be to put that into a more science-astronomy perspective.

I guess where we differ is I think it's perfectly acceptable to describe things in terms of perspective and from the perspective of people in different hemispheres different sides of the moon are illuminated at the quarter moons. By your logic to you object to the phase "close approach" when celestial objects are near to each other? That's simply a matter of perspective too most of the time. I mean even saying "upside down" isn't really accurate as there is no up or down in space---so I think "left side" and "right side" is more correct as it implicitly factors perspective in.

Definitely wanted to phrase this scientific terms, but I'm always awaresome of Space's readers are layman and I think it should be understandable for everyone.

Awesome feedback and certainly food for thought.

Thanks!

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