What is the fate of the universe?

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Discussion Overview

The discussion centers around the concept of the universe's duration, specifically its total lifetime and potential fate. Participants explore various models and theories related to the age of the universe, its expected lifespan, and the implications of these ideas within the context of physics and cosmology.

Discussion Character

  • Exploratory
  • Debate/contested
  • Conceptual clarification
  • Technical explanation

Main Points Raised

  • Some participants seek clarification on whether "duration" refers to the universe's age since the Big Bang or its total lifetime.
  • One participant notes that conventional views estimate the universe to be around 13.7 billion years old, but questions whether time itself began with the Big Bang.
  • Another participant mentions various theories regarding the end of the universe, including concepts like deep freeze and bouncing cosmologies.
  • There is a discussion about the limitations of current quantum theories in measuring times longer than 1018 seconds, which affects how the universe's age is understood.
  • Some participants express uncertainty about the size of the universe, suggesting it may be infinite or finite but not definitively known.
  • One participant emphasizes the importance of understanding the universe's duration for statistical purposes in physics.
  • Another participant suggests that the only observable universe is our own, and its lifespan remains uncertain.
  • A book recommendation is made that explores the age and possible fates of the universe, discussing various models and their dependencies.

Areas of Agreement / Disagreement

Participants generally agree that the age and expected lifespan of the universe are not definitively known, with multiple competing views and theories presented. The discussion remains unresolved regarding the specifics of the universe's duration and fate.

Contextual Notes

Participants highlight the limitations of current models and the dependence on observational data, noting that many aspects of the universe's duration and fate are still speculative.

Unnickporser
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What is the duration of universe?
 
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Unnickporser said:
What is the duration of universe?

Welcome to the PF.

Could you please clarify your question? By '"duration" do you mean how old the universe is now? If so, that is easy to find with Google or Wikipedia.

Or do you mean what would be the total lifetime of the universe? If you mean total lifetime, are you familiar with the difference between "open" and "closed" models of the universe?
 
I think this is a spin of my thread just post on it, it already has a reply from a reputable member which I will be soon to comment on.
 
Well, I referred to duration like I said, to lifetime, not time from big bang. Anyway, in Wikipedia there is only diverse stimation from different models, but not a really response to the question anyway
 
There are different ways to answer the question. The conventional view is the universe arose ~13.7 billion years ago in what is called the Big Bang. It is, however, unclear if time itself originated with the Big Bang, or, the BB was preceded by some yet unknown precursor state or states. Some have even suggested the universe is stuck in a time loop that endlessly repeats [e.g., bouncing cosmologies]. In that sense it could be said the age of the 'universe' [in the sense of all that is or ever was] is undefinable.
 
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Unnickporser said:
Well, I referred to duration like I said, to lifetime, not time from big bang. Anyway, in Wikipedia there is only diverse stimation from different models, but not a really response to the question anyway

If you don't mean lifetime, then what do you mean?
 
I will translate his comment;

"Well, I referred to duration like I said, to lifetime, not time from big bang. Anyway, in Wikipedia there is only diverse stimation from different models, but not a really response to the question anyway"Means: How long will the universe exist for not how long it as has existed.Analysis: He wants to know how long the universe will exist for.

Answer: There are many "end of the universe" theories such as a deep freeze. Or string field theory which has bubbles merging and splitting I guess.They are all theory but are fun to take a look at.
 
But this is a neccesary knowing because finite real statistics used in physics and all of sciences need to know how many times a random phenomemon will ocurr. There are people seeking through Planck units, but , I would like to know it too. What is the duration (from the start to the end), not the actual age of universe? And its dimensions?
 
Garrulo said:
But this is a neccesary knowing because finite real statistics used in physics and all of sciences need to know how many times a random phenomemon will ocurr. There are people seeking through Planck units, but , I would like to know it too. What is the duration (from the start to the end), not the actual age of universe? And its dimensions?

I'm sorry I can't make heads or tails of your post.
 
  • #10
I don´t understand you , sorry, my english no good. Could you tell it about other words
 
  • #11
Garrulo said:
I don´t understand you , sorry, my english no good. Could you tell it about other words

I said, I do not understand your question. Are you asking how big the universe is and how long it will exist?
 
  • #12
Yes, this is my question
 
  • #13
Garrulo said:
Yes, this is my question
Neither the size nor the expected life span of the universe is known.

The size may be infinite or it may be finite but bounded. If it is finite, the size is not known.

There is currently no reason to believe that the lifetime of the universe will be infinite, but in any case, it will certainly last for many orders of magnitude longer than it has so far.
 
  • #14
Garrulo said:
Yes, this is my question

We don't know how big the universe is. We also do not know how long it will exist for.
 
  • #15
Drakkith said:
We don't know how big the universe is. We also do not know how long it will exist for.
Garrulo, as you can see, here on the Physics Forum, some of us like to repeat answers that have already been given. ;)
 
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  • #16
It is said that actual quantum theories can´t measure times longer than 1018 s, and this is the reason because we measure this quantity for the universe age
 
  • #17
Garrulo said:
It is said that actual quantum theories can´t measure times longer than 1018 s, and this is the reason because we measure this quantity for the universe age
Mi question is not trivial. We use probability all times, but probabilities small are not possible in function of the number of experiments that can be done in the universe about the experiment we wish know if a determinate event can ocurr. For example, age of universe is around 1018 s, and universe radius is around 1018 m. An event of an experiment done in a meter length laboratory with duration of one second have a probability of 10-36 can be discharged
 
  • #18
Garrulo said:
It is said that actual quantum theories can´t measure times longer than 1018 s, and this is the reason because we measure this quantity for the universe age
HUH? Where did you hear this? Sounds like nonsense to me. Can you give me a citation?
 
  • #19
Garrulo said:
Mi question is not trivial. We use probability all times, but probabilities small are not possible in function of the number of experiments that can be done in the universe about the experiment we wish know if a determinate event can ocurr. For example, age of universe is around 1018 s, and universe radius is around 1018 m. An event of an experiment done in a meter length laboratory with duration of one second have a probability of 10-36 can be discharged
I can't make any sense at all out of this post. Can you say it differently?
 
  • #20
We do not know the duration of a typical universes lifetime, because the only universe we can observe is our own, and we can't even observe all of it. Our universe right now is to be an estimated 13.8 billion years old; however, that could be only a small chunk of how long they survive for. It could also be long overdue for an end or retraction.

Maybe one day we will come close to an answer, but for now; we have to rely on what we can observe and learn. From there we will gain insight.
 
  • #21
A suggestion for a book that deals with the age and possible fate(s) of the Universe, while exploring the various models and dependencies for each is

The Five Ages of the Universe: Inside the Physics of Eternity by Fred C. Adams and Greg Laughlan, Published by Basic Books, originally in 1999, and a new and updated edition (with considerable revisions based on data observed in the interim) is either shortly pending or just published.

Some links:

https://www.amazon.com/dp/0684865769/?tag=pfamazon01-20
http://en.wikipedia.org/wiki/The_Five_Ages_of_the_Universe
http://search.library.duke.edu/search?id=UNCb3255991
http://www.dogpile.com/search/web?fcoid=417&fcop=topnav&fpid=27&q=the+five+ages+of+the+universe&ql=

I really enjoyed this book. It expresses the various models of what and when. A unitary model is not the Soup of the Day. The book goes into a great deal of detail as to which models are dependent on the answers to specific questions that we may have an idea (but not a confident model) of, such as the possibility of proton decay and what happens if they do/don't, and what are the implications.

The book obviously employs some speculation as to the deep future but it tries to hew as closely as possible to something of an if X then Y model based on mainstream, but not watered down or overly popularized physics. (There are a few 'outside the mainstream' sidebars, but that is more in service to expressing the range and depth of the research landscape).

I am looking forward to reading the revised edition, particularly as the last 15 or so years has revealed and clarified much in this field (and raised other questions as well).

FWIW, Basic Books is a very respectable publisher as regards particularly up-to-the-minute science literature for a general audience.
http://www.basicbooks.com/
http://www.periodicplayground.com/

I suspect that this book might go a long way to satisfying the OP's (and anybody else's, for that matter) curiosity on the subject.

diogenesNY
 
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