What would be the geological consequences of a "big crunch"?

[SEYED2001]

I recently asked a question about the geological consequences of a "big slurp", in which a true vacuum bubble is formed and propopogates at speed of light. Apparently, in this bubble there is a gravitational collapse (https://handwiki.org/wiki/Physics:False_vacuum) so I was wondering what would be the geological consequences of a gravitational collapse. For simplicity let's analyse it in the context if big crunch and not big slurp. More importantly, I wonder if any big earthquake would happen and what would particularly happen to the mountains? will they be collapsed to the ground due to gravity? Will they also start moving?

 

[DaveC426913]

In a Big Crunch, all the matter in the universe eventually collapses back together.

During the last aeons that life might survive, it will presumably be a maelstrom of crashing bodies and pervasive dust and heat.

Space would be much more dense with objects so your mountains would be pulverized by impacts.

There's no reason gravity itself would be different, however, being surrounded by mass in all directions, you'd as likely be pulled up as down.

 

[SEYED2001]

In a Big Crunch, all the matter in the universe eventually collapses back together.

During the last aeons that life might survive, it will presumably be a maelstrom of crashing bodies and pervasive dust and heat.

Space would be much more dense with objects so your mountains would be pulverized by impacts.

There's no reason gravity itself would be different, however, being surrounded by mass in all directions, you'd as likely be pulled up as down.

Thanks for your response, but this entire "big crunch" would happen in a matter of seconds in the bubble so I am wondering what happens from the start to the end of the collapse and not just its end.

 

[DaveC426913]

Thanks for your response, but this entire "big crunch" would happen in a matter of seconds in the bubble so I am wondering what happens from the start to the end of the collapse and not just its end.

What makes you put a time limit on how long a Big Crunch takes?

The sky will be dense with matter and the temperatures far, far too hot for life (and possibly even atoms), this era will last for millions or even billions of years.

 

[SEYED2001]

What makes you put a time limit on how long a Big Crunch takes?

The sky will be dense with matter and the temperatures far, far too hot for life (and possibly even atoms), this era will last for millions or even billions of years.

True, but I am interested in the gravitational collapse that happens inside a bubble of true vaccume in a bug slurp and not a big crunch, with the former taking place in a matter of seconds to milliseconds.

 

[Ibix]

Perhaps you could provide a reference to what you mean by a big crunch. The usual meaning is the final stages of a closed FLRW spacetime, in which at least the last few hundred thousand years would be plasma.

 

[DaveC426913]

True, but I am interested in the gravitational collapse that happens inside a bubble of true vaccume in a bug slurp and not a big crunch, with the former taking place in a matter of seconds to milliseconds.

Sorry, I'm not sure what you're interested in now. There are a lot of unstated assumptions you're making that need to be unpacked.

Suffice to say, no matter how you cut it, the elapsed time between too-hot-to-sustain-life and material-degeneration-due-gravitational-collapse will surely be on the order of aeons, not seconds.

Consider, as a very rough guide, the events of the Big Bang, but in reverse. See here:

https://en.m.wikipedia.org/wiki/Chronology_of_the_universe

 

[DaveC426913]

If,on the other hand, its the slurp you're interested in, we don't really know, but presumably it will come with no warning and will cause atoms to tear themselves apart, releasing heat - ie instant reduction to subatomic particles.

I don't see any reason why there would be a gradual change, and I don't see why gravity would change before the other three MUCH stronger forces do. Gravity is many, many, MANY orders of magnitude weaker than nuclear forces.

 

[SEYED2001]

Dear all, many thanks for your replies. For the gravitational collapse in big slurp (which is what I am interested in), please see the articles by Coleman, Sidney; De Luccia, Frank (1980-06-15). "Gravitational effects on and of vacuum decay". I was thinking (maybe wrongly) that is a gravitational collapse that happens inside a bubble, which according to the article takes a few milliseconds to seconds. I understand your point that changes are sudden and not gradual, but in the unlikely but possible case that this new world in the bubble wasn't much different 5han iurs ane that Earth wasn't vaporised, how would its geology change in a fast-paced gravitational collapse.

 

[DaveC426913]

...how would its geology change in a fast-paced gravitational collapse.

Any way you like.

We are beyond speculation here, and into unfettered imagining.
My unfettered imagining leads me to believe that the strongest forces are the ones that our normal world are most critically dependent on.

A change in the strong nuclear force, for example, need be vanishingly small to corrupt the structure of an atom, and since it need be so small, a vacuum collapse would reach that state very quickly - before any other weaker and less local effect.

On the other hand, it could be dozens and dozens of orders of magnitude (and thus much later in time and separation) before gravity is sufficiently disrupted to cause mere atoms to notice it over atomic distances and times, never mind parts of mountains separated by miles.

But that's me.