Length Contraction: Apple Hanging from Tree & Earth

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Discussion Overview

The discussion revolves around the concept of length contraction as it pertains to an apple hanging from a tree and its relationship with the Earth. Participants explore the implications of length contraction in different frames of reference, particularly focusing on whether the apple and Earth experience any measurable contraction relative to each other.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification

Main Points Raised

  • Henrik questions whether there is length contraction between the apple and the Earth from both the Earth's and the apple's frame of reference.
  • Some participants suggest that since the apple and Earth are co-moving, there may not be a difference to measure for length contraction.
  • One participant emphasizes that length contraction occurs when comparing measurements from two different inertial frames, questioning what measurements are being compared in this scenario.
  • A later reply proposes a hypothetical scenario involving two points at equal distances from the Earth, questioning if the presence of the apple would affect length contraction.
  • Another participant argues that the presence of the apple does not create a difference in distance to the Earth, as both points are equidistant.
  • Henrik speculates that the apple's presence might enhance the gravitational field slightly, potentially leading to spacetime distortion and length contraction, but this is met with skepticism.
  • There is a discussion about the relationship between gravitational fields and spacetime distortion, with some participants indicating confusion over their connection.

Areas of Agreement / Disagreement

Participants do not reach a consensus on whether the apple's presence affects length contraction or spacetime distortion. Multiple competing views remain, particularly regarding the implications of gravitational effects and the nature of measurements involved.

Contextual Notes

There are unresolved assumptions regarding the definitions of length contraction and spacetime distortion, as well as the implications of the apple's mass relative to the Earth.

Hernik
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Hello. Apologies, if this is already answered in other threads. Please redirect me, if that is the case.

Imagine an apple hanging from a tree. Will there be length contraction between the apple and the earth in the frame of reference of the earth, as well as of the apple?

All the best, Henrik
 
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Maybe it is better to ask: Will the apple see a length contraction in the direction of the earth, and will the earth see a length contraction in the direction of the apple (although probably rather small)?
 
"Contraction" implies a difference. In this case, difference with what?
 
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Thanks for your answer. Unfortunately, I don't understand. Apple and earth are co-moving, so no difference there. I suppose.
 
Length contraction is a phenomenon that occurs when comparing measurements made using two inertial reference frames and the object being measured is at rest in one. I don't understand what measurements you are planning on comparing here.
 
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Thank you for helping me fraze this better. Maybe this will do: If you pick two different points at the same distance to the earth: A and B, and in A, an apple is placed, in B, nothing, would there be a length contraction between the apple at A and Earth compared to B and Earth? (Assuming Earth to be a perfect sphere).
 
  • Skeptical
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Sorry about the spelling, phrase, I meant.
 
Hernik said:
If you pick two different points at the same distance to the earth: A and B, and in A, an apple is placed, in B, nothing, would there be a length contraction between the apple at A and Earth compared to B and Earth?
No, because you have specified that A and B are both at the same distance from earth.

But I'm still not sure what you're asking.
Are you asking whether the presence of the apple makes a difference? No, as long as the mass of the apple is negligible compared with that of the earth (and if it is not, we open up a whole different can of worms - let's not go there). The distance between the earth and point in space where the apple is will be the same whether the apple is there or not.

There is a different can of worms, in many ways more interesting, involving how we define/measure that distance. If your question involves opening that one.... by all means do so.
 
Thanks. Well. How to ask a question. I guess, what I am thinking, is along the lines of: I would presume, the apple's presence would enhance the gravitational field slightly between the apple and the earth. And I would further presume that to give rise to a slight spacetime distortion in the area between the apple and the earth. And, that such a spacetime distortion involves a slight length contraction. You say no. I a wrong, right? (edit, spelling)
 
  • #10
...mixing up gravitational field and space time distortion. They are the same, so one not giving rise to the other.. sorry. Apart from that, I am still wrong, I understand?
 
  • #11
Hernik said:
such a spacetime distortion involves a slight length contraction
Nugatory said:
as long as the mass of the apple is negligible compared with that of the earth (and if it is not, we open up a whole different can of worms - let's not go there
 
  • #12
Thanks. Close the thread please.
 

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