TITLE: How is the structure of solid or liquid matter affected at the event horizon of a black hole?
QUESTION [0 upvotes]: I see many answers to what happens to 'an observer' or 'matter' or 'clocks' passing the event horizon of a black hole, but would like to ask how the structure of solid or liquid matter is affected?
For example imagine I push a diamond prism through the event horizon (this is a simple, single element, regular crystalline structure), maintained by inter-atomic forces. If I regard the prism as a collection of atoms, maintained in their relative positions through those inter-atomic forces, then how are the inter-atomic nearest-neighbour connections affected as they cross the event horizon? An atom within the event horizon cannot affect one outside, so presumably the connection is broken and the material is disrupted, but I'd like to understand a bit more about what happens and why.
For another example imagine a liquid whose structure is maintained, if you like, by inter-molecular collisions. Again, a molecule within the event horizon cannot collide with one outside, so presumably again the material is disrupted?
For context, this question arose from a silly suggestion I made, that one might build a tower that extended outside the event horizon and then put an elevator in it to move in and out. I 'know' that doesn't work but I am not quite clear about the mechanisms when we think about real material with its interatomic forces rather than idealised 'matter'.

REPLY [0 votes]: I am no expert on this topic but from what I have read the amount of disruption to a material body as it crosses the EH depends on the size of the black hole.  For very large black holes nothing much happens as the EH is crossed because the distance to the singularity is very large compared to the size of the object so all parts of the object feel effectively the same force.  As the size of the black hole decreases the size of the object compared to the distance to the singularity decreases and eventually the force difference on various parts of the object overcomes the binding forces and the object is disrupted. Check out this link for more info: https://www.phenomena.org/space/spaghettification/
{"set_name": "stack_exchange", "score": 0, "question_id": 593379}