<p>I think there is a real question in there, just not the one that you think.</p>

<p>Gerald isn't saying that the uncertainty principle played a role in the big bang.   He's saying it played a role in and shortly after the Planck era which came after the big bang.  </p>

<p>On the big bang - nobody knows.   Really, that's the answer.  "Was the big bang this" answer "We don't know".   Period.   End of discussion.  </p>

<p>We don't know what came before the big bang, We don't know if space was empty or not empty.  We don't know what physical laws may have applied.  Nobody knows.   The initial, basic theory was that the big bang happened at a point or a singularity, which if you think about it, doesn't make much sense cause gravity wins at a point that dense, but the big bang at a point idea does resemble, kinda/sorta a really crazy particle that, by something kinda like quantum tunneling, could become a universe - er, maybe.   String Theory brings other dimensions into this particle becomes a universe - idea, and again, maybe, but nobody knows.</p>

<p>A more modern model, but still, we don't know, is that the universe was infinite at the time of the big bang expansion, and it grew, not from a point but it expanded from infinite into infinite, which works mathematically and it makes (I think) a bit more sense than the super-particle model.  Still the answer is "We don't know".   The answer is always "We don't know".   There's also 4 dimensional models or two time dimension models (those are my favorite when you have x-axis and y-axis time), which are creative ways to avoid the singularity but . . . I'm repeating myself.  Nobody knows.  The answer to what happened at the big bang is always nobody knows.  We don't know if it was empty or not, we don't know if there was some 4th dimensional crossing of <a href="https://en.wikipedia.org/wiki/M-theory" rel="nofollow noreferrer">membranes</a> which caused the 3d universe we live in.</p>

<p>Now, on modeling back to the big bang, the experts can run the model backwards and apply known laws and have a theory that works to a time shortly after the big bang, which still isn't certainty, but it's a reasonable hypothesis using the laws of physics as they work today.  But it doesn't work all the way back to the big bang.</p>

<p>So, the paragraph that you quote, I think there's a solid question in there, but the quote doesn't mean what you think. </p>

<blockquote>
  <p>You may think of the pre-Planck and the Planck epoch as a state of the universe, which is dominated by quantum fluctuations. They don't need a reason or a cause to occur. They are a consequence of Heisenberg's uncertainty principle.</p>
  
  <p>So,Did any law like uncertainty principle caused this to be happened or any somethings?</p>
</blockquote>

<p>Gerald is talking about a period AFTER the big bang and what the models tell us about that period when the universe was, (theoretically), very dense and very hot and governed by quantum mechanics.  </p>

<p>Perhaps a better question, which I'm not qualified to answer but might be worth asking, is, "<em>how did the uncertainty principle apply during and shortly after the Planck Era</em>" - at least, that's the question I take away from the paragraph you quoted.   Gerald didn't say the uncertainty principal applied to the big bang, only to the Planck Era.  </p>

CC BY-SA 3.0
2017-01-12T23:07:02.547Z
2017-02-06T11:23:49.413Z
2017-02-06T11:23:49.413Z
userLTK
<p>So i want to know why world changed from the empty state ( no materials, energy and ...) from to the it's staring state in the big bang shape?</p>

<p>based of this answer's to this question:
<a href="https://astronomy.stackexchange.com/questions/2342/big-bang-thoery-what-triggered-it-and-why?rq=1">big-bang-thoery-what-triggered-it-and-why</a>
they said:</p>

<blockquote>
  <p>You may think of the pre-Planck and the Planck epoch as a state of the
  universe, which is dominated by quantum fluctuations. They don't need
  a reason or a cause to occur. They are a consequence of Heisenberg's
  uncertainty principle.</p>
</blockquote>

<p>So,Did any law like uncertainty principle caused this to be happened or any somethings? </p>

<p>Or </p>

<p>This is one meaningless question?!!!</p>

<p>Thanks a lot.</p>

CC BY-SA 3.0
2017-01-12T00:56:45.957Z
Every physicist wants to know how the universe came into being.  No-one knows.
StephenG - Help Ukraine
CC BY-SA 3.0
2017-01-12T20:27:16.923Z
I do try to understand questions from non-native users of English, but this is very hard to follow. I don't know what you mean by the "empty state" (the universe has never been empty). I don't know what you mean by the "big bang shape". I suspect if this question were clarified it would be too broad.
James K
CC BY-SA 3.0
2017-01-13T14:38:23.343Z
"Quantum fluctuation" is the term commonly used.
Wayfaring Stranger
CC BY-SA 3.0
2017-01-13T14:38:27.660Z
I'm voting to close this question as off-topic because nobody knows exactly how the universe came into being, and it's currently impossible to answer a question like this. It's also a little unclear.
HDE 226868
<big-bang-theory>
Did uncertainty principle triggered big bang?
Soheil Paper
# Did uncertainty principle triggered big bang?

(Asked by: username_0 on 2017-01-12)

So i want to know why world changed from the empty state ( no materials, energy and ...) from to the it's staring state in the big bang shape?

based of this answer's to this question:
[big-bang-thoery-what-triggered-it-and-why](https://astronomy.stackexchange.com/questions/2342/big-bang-thoery-what-triggered-it-and-why?rq=1)
they said:

> You may think of the pre-Planck and the Planck epoch as a state of the
> universe, which is dominated by quantum fluctuations. They don't need
> a reason or a cause to occur. They are a consequence of Heisenberg's
> uncertainty principle.

So,Did any law like uncertainty principle caused this to be happened or any somethings?

Or

This is one meaningless question?!!!

Thanks a lot.

**Tags:** big-bang-theory

> **Comments:**
> **username_1**: Every physicist wants to know how the universe came into being.  No-one knows.  
> **username_2**: I do try to understand questions from non-native users of English, but this is very hard to follow. I don't know what you mean by the "empty state" (the universe has never been empty). I don't know what you mean by the "big bang shape". I suspect if this question were clarified it would be too broad.  
> **username_3**: "Quantum fluctuation" is the term commonly used.  
> **username_4**: I'm voting to close this question as off-topic because nobody knows exactly how the universe came into being, and it's currently impossible to answer a question like this. It's also a little unclear.  

---

## 1 answers

### Answer by username_5 on 2017-01-12. Score: 1

I think there is a real question in there, just not the one that you think.

Gerald isn't saying that the uncertainty principle played a role in the big bang. He's saying it played a role in and shortly after the Planck era which came after the big bang.

On the big bang - nobody knows. Really, that's the answer. "Was the big bang this" answer "We don't know". Period. End of discussion.

We don't know what came before the big bang, We don't know if space was empty or not empty. We don't know what physical laws may have applied. Nobody knows. The initial, basic theory was that the big bang happened at a point or a singularity, which if you think about it, doesn't make much sense cause gravity wins at a point that dense, but the big bang at a point idea does resemble, kinda/sorta a really crazy particle that, by something kinda like quantum tunneling, could become a universe - er, maybe. String Theory brings other dimensions into this particle becomes a universe - idea, and again, maybe, but nobody knows.

A more modern model, but still, we don't know, is that the universe was infinite at the time of the big bang expansion, and it grew, not from a point but it expanded from infinite into infinite, which works mathematically and it makes (I think) a bit more sense than the super-particle model. Still the answer is "We don't know". The answer is always "We don't know". There's also 4 dimensional models or two time dimension models (those are my favorite when you have x-axis and y-axis time), which are creative ways to avoid the singularity but . . . I'm repeating myself. Nobody knows. The answer to what happened at the big bang is always nobody knows. We don't know if it was empty or not, we don't know if there was some 4th dimensional crossing of [membranes](https://en.wikipedia.org/wiki/M-theory) which caused the 3d universe we live in.

Now, on modeling back to the big bang, the experts can run the model backwards and apply known laws and have a theory that works to a time shortly after the big bang, which still isn't certainty, but it's a reasonable hypothesis using the laws of physics as they work today. But it doesn't work all the way back to the big bang.

So, the paragraph that you quote, I think there's a solid question in there, but the quote doesn't mean what you think.

> You may think of the pre-Planck and the Planck epoch as a state of the universe, which is dominated by quantum fluctuations. They don't need a reason or a cause to occur. They are a consequence of Heisenberg's uncertainty principle.
>
> So,Did any law like uncertainty principle caused this to be happened or any somethings?

Gerald is talking about a period AFTER the big bang and what the models tell us about that period when the universe was, (theoretically), very dense and very hot and governed by quantum mechanics.

Perhaps a better question, which I'm not qualified to answer but might be worth asking, is, "*how did the uncertainty principle apply during and shortly after the Planck Era*" - at least, that's the question I take away from the paragraph you quoted. Gerald didn't say the uncertainty principal applied to the big bang, only to the Planck Era.


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