How do we study space-time singularities?

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Discussion Overview

The discussion centers on the study of space-time singularities, particularly in the context of black holes and the Big Bang. Participants explore how scientists approach these singularities, the limitations of empirical study, and the theoretical implications of general relativity (GR) in extreme conditions.

Discussion Character

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

Main Points Raised

  • Some participants note that singularities represent points where mathematical models break down, making empirical study impossible for certain types, such as those at the center of black holes and the Big Bang.
  • One participant questions why scientists continue to study singularities if they cannot be empirically observed and seeks clarification on how research is quantified.
  • Another participant explains that singularities arise as predictions of GR under extreme conditions, suggesting that while GR may not apply in these cases, it remains valid in less extreme scenarios.
  • Some participants mention the need for a theory of quantum gravity to reconcile the discrepancies between GR and quantum mechanics at singularities.
  • A participant expresses confusion about the nature of singularities beyond the observable universe and questions whether they can be classified as singularities.
  • There are differing views on what lies beyond the observable universe, with some suggesting it is simply more of the same types of galaxies, while others propose theories about the universe's end, such as the Big Crunch or heat death.

Areas of Agreement / Disagreement

Participants generally agree that singularities pose significant challenges for empirical study and theoretical understanding. However, multiple competing views remain regarding the implications of these singularities and the nature of the universe beyond the observable limits.

Contextual Notes

Participants express uncertainty about definitions and the implications of singularities, highlighting the complexity of the topic and the limitations of current models. There is also mention of unresolved mathematical steps and the dependence on theoretical frameworks.

Pbody101
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I hope I am posting this in the correct forum, I am trying to better understand space-time singularities. I can find easily the basic, and advanced information on what it is and the different theories. My main question is how do scientists study these space-time singularities?

Thank you for your help.

P
 
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Pbody101 said:
I hope I am posting this in the correct forum, I am trying to better understand space-time singularities. I can find easily the basic, and advanced information on what it is and the different theories. My main question is how do scientists study these space-time singularities?

Thank you for your help.

P
You need to be more specific since "singularity" just means "the place where the math model breaks down and we don't know WHAT is going on". Which singularity do you have in mind? The singularity at the center of a black hole can't be "studied" in any empirical sense because it is causally removed from our universe and the Big Bang singularity is, as far as we are aware, unavailable for empirical study.
 
I had a feeling I was being vague, excuse my ignorance. I was trying to understand a little bit more about black hole singularities, as well as the big bang singularity. Although I think you did answer my question, we cannot study these singularities, and it's "the place where the math model breaks down, and we don't know what is going on."

If we cannot study these, why do scientists work on them and how do they quantify their research. If you can lead me to links for more reading that would be awesome.

Thank you

P
 
The singularities arise as a prediction of GR in extreme circumstances (black holes, and a different kind of singularity for the big bang).
Since it is impossible to observe what actually happens in these circumstances empirically, the only available approach is to mathematically extend upon GR, on the assumption that in these extreme circumstances it is not applicable, something else is going on.
That doesn't mean GR is 'wrong' though, just that it is incomplete, it still describes spacetime perfectly for cases other than the extremes.
 
I don't have any links to anything but I can tell you that the reason for examining the singluarity at the center of a black hole is because that's where GR and Quantum Mechanics don't play well together and we need a theory of quantum gravity.
 
Thank you phinds and rootone, I appreciate your answer it definitely helped lead me in a more specific direction. If I have anything more to add so I am not vague I think I will come back to this thread.

For now take care

P
 
I just had an idea, and I don't know what else to do with my ideas other than google them so I did. I Googled: Is what is after the observable universe a singularity because this is now what I have come to understand singularities as "the place where the math model breaks down and we don't know WHAT is going on" . The first link it brought me to was https://profmattstrassler.com/2014/03/21/did-the-universe-begin-with-a-singularity/. Did the universe begin with a singularity, which clearly does not remotely answer my question. As I began to type this I realize it has to be, in the definition of the math model breaks down and we don't have a clue of what's going on.

So I stumbled upon this and perhaps this is what I was looking for with my first question, although I am not entirely sure: "So there were a number of attempts to get round the conclusion, that there was a singularity of infinite density in the past. "

"The conclusion of this lecture is that the universe has not existed forever. Rather, the universe, and time itself, had a beginning in the Big Bang, about 15 billion years ago. The beginning of real time, would have been a singularity, at which the laws of physics would have broken down."

http://www.hawking.org.uk/the-beginning-of-time.html

And I can see how we would have no idea what is going on, but I would still like to know more. So the research continues.

Thanks

P
 
I cannot edit, sorry I will preview before I post from now on.

Googled: What is after the observable universe, a singularity? Because now I have come to understand singularities can be described as "the place where the math model breaks down and we don't know WHAT is going on" .
 
What is expected to lie beyond the visible Universe is ...
nothing spectacular,
just more of the same kinds of galaxies in a similar distribution to those that are inside the observable sphere.
 
Last edited:
  • #10
Pbody101 said:
I just had an idea, and I don't know what else to do with my ideas other than google them so I did. I Googled: Is what is after the observable universe a singularity because this is now what I have come to understand singularities as "the place where the math model breaks down and we don't know WHAT is going on" .
The math model does NOT break down after the observable universe. As rootone said, it's just more of the same.
 
  • #11
Pbody101 said:
Googled: What is after the observable universe, a singularity? Because now I have come to understand singularities can be described as "the place where the math model breaks down and we don't know WHAT is going on" .
Since you keep referring to a singularity: are you trying to ask what happens when the universe ends? If so, the theory before expansion was discovered to be accelerating was the big crunch, which ends in a singularity. The current theory is the universe will end in heat death, or thermodynamic equilibrium.

https://en.m.wikipedia.org/wiki/Heat_death_of_the_universe
https://en.m.wikipedia.org/wiki/Big_Crunch
 
  • #12
stoomart said:
Since you keep referring to a singularity: are you trying to ask what happens when the universe ends? If so, the theory before expansion was discovered to be accelerating was the big crunch, which ends in a singularity. The current theory is the universe will end in heat death, or thermodynamic equilibrium.

https://en.m.wikipedia.org/wiki/Heat_death_of_the_universe
https://en.m.wikipedia.org/wiki/Big_Crunch
Hello Stoomart, no I wasn't trying to ask what happens when the universe ends. I am trying to do research of when the universe began, just like anything a study it seems like a bunch of rabbit holes. But I am glad you brought up the theory of what may happen when the universe ends, because after a few months of studying the beginning I will be looking at the ending.

Thank you for your reply

p
 
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