How Do Tidal Forces Affect Objects Near Black Holes?

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Discussion Overview

The discussion revolves around the effects of tidal forces on objects near black holes, specifically comparing conditions outside and inside the event horizon. Participants explore theoretical implications and interpretations of tidal forces in both regions, touching on concepts like spaghettification and the behavior of light cones near singularities.

Discussion Character

  • Exploratory
  • Technical explanation
  • Debate/contested

Main Points Raised

  • Some participants suggest that outside the horizon, objects are torn apart in the vertical direction while being squeezed horizontally, whereas inside the horizon, they continue to be torn apart vertically and also horizontally.
  • Another viewpoint emphasizes that objects are stretched radially and squashed horizontally, referencing the concept of spaghettification or the "toothpaste effect." This perspective includes a method for measuring r-values for free-falling observers inside a black hole.
  • One participant challenges the applicability of external tidal force equations to the interior of black holes, arguing that the singularity behaves differently for free-falling observers and that tidal forces may act in all directions as objects approach the singularity.
  • Another participant asserts that the equations for tidal forces remain unchanged across the event horizon, providing a link to a resource that discusses the compacting of distances for free-falling objects within the horizon.

Areas of Agreement / Disagreement

Participants express differing views on the behavior of tidal forces inside and outside the event horizon, with no consensus reached on the nature of these forces or their implications for objects near black holes.

Contextual Notes

Some claims rely on specific interpretations of tidal forces and the behavior of light cones, which may depend on the definitions and assumptions made about black hole physics. The discussion includes references to external resources for further exploration of the topic.

Dmitry67
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Please confirm, I am not sure.

Outside the horizon, object is torn apart in vertical direction but is squezzed in a horizontal.
Inside the horizon, object is still torn apart in a 'vertical' direction, and in in the horizontal direction too
 
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Dmitry67 said:
Outside the horizon, object is torn apart in vertical direction but is squezzed in a horizontal.
Inside the horizon, object is still torn apart in a 'vertical' direction, and in in the horizontal direction too

The object is stretched in the radial direction and squashed in the horizontal direction (sometimes reffered to as 'http://en.wikipedia.org/wiki/Spaghetiffication" ' or 'the toothpaste effect'). Measuring the rate of contraction in the horizontal is one way a free-falling observer might be able to measure r-values once inside a static black hole (see page B-8 in 'Exploring Black Holes' by Taylor and Wheeler).

Regarding tidal forces inside black holes-
http://io.uwinnipeg.ca/~vincent/4500.6-001/Cosmology/Tidal_Forces_%20In_%20A_%20Black_%20Hole.htm
 
Last edited by a moderator:
I believe your link is still about the outside region.
Singularity in the non-rotating black hole is spacelike for a free falling obser4ver, it is not the point.

I am an amateur, so I check the pictures:
http://www.phy.syr.edu/courses/modules/LIGHTCONE/pics/bh3.gif
http://nrumiano.free.fr/Images/lightcones_E.gif

Approaching the singularity, lightcones become sharper and sharper. So any close objects will sooner or later lose connection to each other. The lightcones which become narrower and narrower is exactly the BIG RIP metrics. So tidal forces are ripping all apart in ALL directions.
 
Last edited by a moderator:
The equation for tidal forces remains unchanged inside and outside the event horizon.

Click on the link below (which leads to a draft copy of the second edition of EBH available online), then on 'InsideBH090308v1.pdf' which will open a new window, go to page 7 and you'll see an explanation regarding how distances compact for free-falling objects in the horizontal direction within the event horizon and how this can be used to measure the r-coordinate-

http://exploringblackholes.com/

Better still, I recommend you buy the book as it should answer most of your questions.
 

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