How would this work on the moon? theory

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Discussion Overview

The discussion explores the behavior of objects, such as a rope or a flag, on the moon, particularly focusing on the effects of the moon's vacuum environment on motion and inertia. Participants consider how these objects would respond to movement without atmospheric resistance, comparing it to similar scenarios on Earth.

Discussion Character

  • Exploratory, Conceptual clarification, Debate/contested

Main Points Raised

  • One participant questions how a rope would behave when moved parallel to the moon's surface, considering the effects of gravity and the absence of atmosphere.
  • Another participant emphasizes the role of inertia, suggesting that flexible objects will still follow a similar initial motion pattern as on Earth, though the exact pattern is uncertain.
  • A different participant proposes that the lack of atmospheric drag and reduced gravity would cause the lower part of a handkerchief to move faster than it would on Earth, while still being affected by inertia.
  • One participant references a video of a moon walk, noting that a flag appears to wave due to the motion of its support rather than wind, which raises questions about the visual effects of movement in a vacuum.
  • Another participant mentions the interpretation of the flag's movement by conspiracy theorists, indicating a misunderstanding of the physics involved.

Areas of Agreement / Disagreement

Participants express varying views on the specifics of how objects would behave on the moon, particularly regarding the effects of inertia and the absence of atmospheric resistance. There is no consensus on the exact nature of the motion.

Contextual Notes

Participants do not fully resolve the assumptions about inertia and atmospheric effects, leaving open questions about the precise dynamics involved in the moon's environment.

howsitwork
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how would this work on the moon?? theory..

i already posted this in the astrophysics forum, but i know this is visited a lot more, and this isn't that advanced. it's also kind of time-sensitive, so i figured id post here in hopes someone stumbles along and knows how to explain it.. thanks..

basically I am thinking this, if you were in a complete vacuum, say, on the moon, and held down a rope from your hand, it would be mildly pulled toward the center of the moon, but if you were to move your hand parallel to the moon's surface (like from straight out in front of you, perpendicular to your chest, and moved it ninety degrees to straight in line with your shoulders), how would the rope follow? would it follow the same as on earth? would the 'delay' be the same. as in would the top (your hand) move first and fastest and would the rest of the rope follow as what happens here?? what about a flag, or hankerchief held spread out, and you moved it closer or farther from you, like a bull-fighter, what would that motion visibly look like? how would the lack of atmosphere and wind resistance effect it??

im more questioning the bull-fighter part. i know the flag would want to stay straight perpendicular to the moon due to gravity, but how would it's movement be effected considering there's no resistance from air, wind, or atmosphere?? thanks.
 
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Welcome to PF, Howsitwork.
You're forgetting about inertia. Any flexible object will still follow the same basic initial pattern as it would on Earth, because the mass of the object will be reluctant to move. I can't tell you what exact pattern it will be, but I'm sure that someone else here can.
 
Howsitwork,

I think you pretty much covered it. Due to lack of atmospheric drag and less gravity, the lower part of the handkerchief should "drag-along" faster than it would on Earth. As Danger already mentioned, the inertia will still make it drag along rather than moving in sync with your hand (top portion of the handkerchief). I would assume that the lack of atmosphere plays the greatest role in making the difference here since you are talking about a loose material like handkerchief.
 
I believe that in one of the videos of a moon walk you can see a flag "waving" due the effect you are asking about. The top edge of the flag is supported by a stiff wire so it hangs as if there were a strong wind, the bottom edge of the flag waves as if it were being blown, but it is just the motion of the support causing the flag to move.
 
Yeah, that's a favourite target of the 'faked moon landing' conspiracy theorists. They can't understand why the flag was 'waving' without air.
 

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