Can someone explain to me this about gravity please

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    Explain Gravity
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Discussion Overview

The discussion centers around the nature of gravity and its range of influence, specifically whether gravity has a limited range or if it can be considered infinite. Participants explore the implications of the gravitational force equation and the concept of infinity in this context.

Discussion Character

  • Exploratory, Technical explanation, Debate/contested

Main Points Raised

  • One participant questions whether gravity has a limited range, noting confusion about the implications of an infinite range and the gravitational force equation F = G(m1m2)/r^2.
  • Another participant clarifies that while the force approaches zero as the distance r approaches infinity, this does not imply that gravity has a limited range, suggesting that for any finite distance, the gravitational force remains non-zero.
  • A third participant emphasizes that infinity should not be treated as a number, arguing that the concept of infinite range means that any finite distance will yield a non-zero gravitational force.
  • One participant points out that a force with a finite range would have a specific cutoff distance beyond which the force would be zero, contrasting this with the properties of gravity.

Areas of Agreement / Disagreement

Participants express differing views on the interpretation of gravity's range, with some asserting that gravity's influence is effectively infinite for finite distances, while others emphasize the mathematical implications of treating infinity in the context of the gravitational force equation.

Contextual Notes

Participants highlight the importance of understanding the distinction between finite distances and infinity, as well as the implications of the gravitational force equation in this discussion.

Abidal Sala
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Does gravity have a limited range in which it can attract objects? I looked up on google, most people are saying it's infinite.. if it really is infinite then I'm confused, because if the denominator is infinite, then the result is just zero.. and in gravity's law F=[g(m1m2)] / r^2 .. if r is so big doesn't gravity simply become ineffective? so how would gravity have an infinite range?

Sorry if this question is silly I'm not a specialist.. I'm just curious
 
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The basic equation is - as you have said

##F = G \frac{m_1\,m_2}{r^2}##

Of course the force F goes to zero if r goes to infinity. But that's not how we would interpret infinite range. We should better say that if we let the distance r become arbitrary large but finite, then the force F becomes small but not zero.
 
The problem is that you are trying to treat infinity as if it were a number- and it isn't. Yes, if you were to replace "r" with infinity you would get a force of 0. But saying that the "range of gravity is infinite" just means that if you were to put any distance in for r you would get a non-zero gravitational force. That does not include setting r equal to "infinity" because, as I said, infinity is not a number and you cannot be an infinite distance away from a gravitating body.
 
yeah. Something with a finite range would have some cut-off ##r## value, and for any ##r## greater than this, the force is zero. (and gravity does not have this property).
 

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