Did the universe Absolutely begin?

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SUMMARY

The discussion centers on the question of whether the universe had an absolute beginning. Participants agree that current scientific understanding, particularly through models like cosmic inflation and the Penrose-Hawking singularity theorems, suggests that while the observable universe began approximately 13.8 billion years ago, the question of what preceded this event remains unresolved. Theories such as string theory and loop quantum gravity are proposed as potential frameworks for understanding the universe's origins, but none have been empirically validated. Ultimately, the consensus is that without a complete theory of quantum gravity, definitive answers about the universe's beginning are unattainable.

PREREQUISITES
  • Understanding of cosmic inflation and its implications for the early universe.
  • Familiarity with the Penrose-Hawking singularity theorems in general relativity.
  • Knowledge of quantum mechanics and its role in subatomic particle behavior.
  • Awareness of theoretical frameworks like string theory and loop quantum gravity.
NEXT STEPS
  • Research the implications of cosmic inflation on the observable universe.
  • Study the Penrose-Hawking singularity theorems and their significance in cosmology.
  • Explore the current state of quantum gravity theories, including string theory and loop quantum gravity.
  • Investigate the philosophical implications of metaphysical questions in relation to scientific inquiry.
USEFUL FOR

Astronomers, physicists, cosmologists, and anyone interested in the fundamental questions of the universe's origins and the intersection of physics and philosophy.

JhonnyDx
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Did the universe Absolutely begin?
 
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JhonnyDx said:
Did the universe Absolutely begin?
Your question is extemely vague. What does "absolutely begin" even mean?

In answer to what I THINK you are asking, the answer is we don't know
 
Absolutely begin, In the sense of undeniable, and very, very likely.
 
JhonnyDx said:
Absolutely begin, In the sense of undeniable, and very, very likely.
Then the answer remains, we don't know.
 
What is more likely?
 
JhonnyDx said:
What is more likely?
We don't know. It's turtles all the way down.
 
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There's no way to know at present what happened (if anything) before our region of space-time began.

One reason for this is that cosmic inflation, which is one of the prevailing models for the early universe, wipes out almost all information about what the universe was like prior to inflation. Without evidence, we can't say what happened before that (if anything).
 
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The question is not knowing what was "before" (because time would also have begun), but if at some "moment" there was no universe.
 
The universe we currently live in begins at every given moment.
 
  • #10
JhonnyDx said:
The question is not knowing what was "before" (because time would also have begun), but if at some "moment" there was no universe.

And again, we don't know. I take it you are just not going to take that for an answer and you are going to continue to ask questions that end up at the same place. Seems like a waste of time, but good luck.
 
  • #11
If you are asking if a state unlike like that of the current universe preceded it, the answer is clearly yes. If you are asking if a state of absolute nothing preceded that of the currently known universe, that's more complicated. It starts with an argument in semantics [like how you define 'absolute nothing'?]. In the philosophical sense, absolute nothing never has and never will exist anywhere in the universe. That would imply a ponderable property enabling you to distinguish it from a pure state of nonexistence.
 
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  • #12
JhonnyDx said:
if at some "moment" there was no universe.

What does this mean?

The fact that you keep on getting vague responses is because your questions are vague. I would advise taking a step back and thinking very carefully about what, exactly, you want to ask. It might help to ask yourself, what observations could we make (even if they're not at all practical, just possible in principle) that would tell us whether the answer to your question is yes or no? If you can't think of any, that's a red flag that your question is too vague.
 
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  • #13
If 'there is no Universe' then there is no anything.
Nothing happens.
Ever.
 
  • #14
Scientists really need to get to the bottom of this. These questions are bugging a lot of people and it would help to have some answers.
 
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  • #15
lifeonmercury said:
Scientists really need to get to the bottom of this. These questions are bugging a lot of people and it would help to have some answers.

Hey, if you know a way to see past the CMB, invent brand new mathematical, philosophical, and scientific concepts that probably don't exist yet, and have the ability (and resources) to quickly develop the equipment necessary to carry out new observations to confirm these theories, please let scientists know.

If you don't, then just try to have a little patience. It's taken about 13 billion years to get to this point. It may take a few years more to find the answer.
 
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  • #16
Scientists _do_ think about it.

More precisely, they are trying to develop mathematically valid theories which explain how Big Bang started. Of course, there are also alternatives where time is infinite in the past direction too, not only in the future direction (for example, "eternal inflation" models), and thus in these models there is no beginning.

It's quite possible that several different fully consistent models will eventually be developed, but we won't be able to find any empirical means to distinguish them. Seeing 13bn years back into the past and past CMB "wall" is very hard.
 
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  • #17
houlahound said:
The universe we currently live in begins at every given moment.

Is it starting every moment?
 
  • #18
[quote = "phinds, pós: 5644881, membro: 310841"] E mais uma vez, nós não sabemos. Acho que você simplesmente não vão tomar isso como uma resposta e você vai continuar a fazer perguntas que acabam no mesmo lugar. Parece ser um desperdício de tempo, mas boa sorte. [/ QUOTE]

Thanks for your response. More sorry for my ignorance of wanting to hear what others have to say; Because you are the owner of the truth.
 
  • #19
[QUOTE = "Chronos, post: 5644961, membro: 10970"] Se você está perguntando se um estado diferente de como a do atual universo precedeu, a resposta é claramente sim. Se você está perguntando se um estado de absoluta nada precedeu a do universo conhecido atualmente, isso é mais complicado. Ela começa com uma discussão na semântica [como como você define "nada absoluto"?]. No sentido filosófico, nada absoluto nunca foi e nunca vai existir em qualquer lugar do universo. Isso implicaria uma propriedade ponderável permitindo-lhe distingui-lo de um puro estado de inexistência. [/ QUOTE]

Was talking about the absence of space-time reality as a whole. Was the uniqueness eternal? Was it material?
 
  • #20
JhonnyDx said:
Was talking about the absence of space-time reality as a whole. Was the uniqueness eternal? Was it material?

Sorry, this doesn't make your question any less vague.

(Also, your quote of my post appears to be translated into Spanish.)
 
  • #21
Excuse me. Plus I do not understand your placement. It's a simple question: did the universe have a beginning?
 
  • #22
JhonnyDx said:
It's a simple question: did the universe have a beginning?

The answer to this question is, we don't know. We have models in which it did, and models in which it didn't. We don't have enough evidence to distinguish between them.
 
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  • #23
Your question isn't answerable by science or physics. Your question is a metaphysical one, one whose answer depends upon your worldview, your presuppositions. It is important for scientists to know when physics ends and metaphysics begins.
 
  • #24
James Heimbach said:
Your question isn't answerable by science or physics.
That is not known to be true. It MIGHT be true but it might not so it is just a personal theory.
 
  • #25
phinds said:
That is not known to be true. It MIGHT be true but it might not so it is just a personal theory.

Let's not get used to using the term "personal theory" too loosely. His statement is by no means a personal theory.
 
  • #26
Drakkith said:
Let's not get used to using the term "personal theory" too loosely. His statement is by no means a personal theory.
Well, personal opinion then. It's certainly not demonstrable fact (though I happen to agree w/ it).
 
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  • #27
James Heimbach said:
Your question isn't answerable by science or physics.

This statement is too strong. It is possible that we might eventually figure out a way to test the various proposed models and be able to rule out either all of the ones in which the universe has a beginning, or all the ones in which it doesn't. We don't know how to do that now, but that doesn't mean we never will.

If you were to say "Your question isn't currently answerable by science or physics", I would agree with that (in fact I already did earlier in this thread).
 
  • #28
James Heimbach said:
Your question isn't answerable by science or physics. Your question is a metaphysical one, one whose answer depends upon your worldview, your presuppositions. It is important for scientists to know when physics ends and metaphysics begins.
Physics ends when the ideas in discussion cannot be tested by observing and measuring stuff.
 
  • #29
JhonnyDx said:
Did the universe Absolutely begin?

i feel the responses to your question have been a little abrupt so Ill try and give you a fuller answer.
The observable universe is expanding and so if we wind the clock back its contracting.
There are theorems in general relativity ( our best theory of the large scale behaviour of the cosmos) called Penrose Hawking singularity theorems that imply that the space time somehow comes to an end in a finite amount of time about 13.8 billion years ago.
Some people interpret this as saying the universe had a beginning 13.8 bio years ago. But the problem here is that if these theories are right then the entire observable universe was once smaller than an atom. Under these conditions we need to take into account quantum mechanics ( our theory that describes the behaviour of sub atomic particles and more). The singularity theorems do not take account of quantum mechanics. So we need a a theory that combines quantum mechanics and general relativity. Alas we have no well verified theory that does this. We do have proposals that scientists take seriously like string theory and loop quantum gravity. People have used these theories to try and work out what happened at the big bang. A common prediction is that the big bang is replaced by a big bounce, so the universe was contracting before it was expanding. But these theories have not been verified by experiments, so these and other similar statements are speculative. Until we get a full theory of quantum gravity and have it verified by experiment we are not likely to know the answer to your question.
Even if we get the full theory we still might not know the answer to question. So I think a theory of quantum gravity is a necessary condition but it remains to be seen if it is sufficient condition. Since the necessary condition has not been fulfilled the answer to your question is right now: "we don't know". Anyone that claims to say with any high degree of confidence that the universe had a beginning or is eternal into the past in my opinion is over stepping that mark. I hope that provides you with a fuller answer to your question.
 
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  • #30
windy miller said:
i feel the responses to your question have been a little abrupt so Ill try and give you a fuller answer.
The observable universe is expanding and so if we wind the clock back its contracting.
There are theorems in general relativity ( our best there of the large scale behaviour of the cosmos) called Penrose Hawking singularity theorems that imply that the space time somehow comes to an end in a finite amount of time about 13.8 billion years ago.
Some people interpret this as saying the universe had a beginning 13.8 bio years ago. But the problem here is that if these theories are right then the entire observable universe was once smaller than an atom. Under these conditions we need to take into account quantum mechanics ( our theory that describes the behaviour of sub atomic particles and more). The singularity theorems do not take account of quantum mechanics. So we need a a theory that combines quantum mechanics and general relativity. Alas we have no well verified theory that does this. We do have proposals that scientists take seriously like string theory and loop quantum gravity. People have used these theories to try and work out what happened at the big bang. A common prediction is that the big bang is replaced by a big bounce, so the universe was contracting before it was expanding. But these theories have not been verified by experiments, so these and other similar statements are speculative. Until we get a full theory of quantum gravity and have been it verified by experiment we are not likely to know the answer to your question.
Even if we get the full theory we still might not know the answer to question. So i think a theory of quantum gravity is a necessary condition but it remains to be seen if it is sufficient condition. Since the necessary condition has not been fulfilled the answer to your question is right now: "we don't know". Anyone that claims to say with any high degree of confidence that the universe had a beginning or is eternal into the past in my opinion is over stepping that mark. I hope that provides you with a fuller answer to your question.

Thank you for taking the time and care to summarize the relevant details, without actively trying to make the questioner feel stupid.
 
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