<p>Big Bang theory is rather adequate, with respect to observations. But it's incomplete. Your question is about the pre-planck epoch, a state of the universe, when space and time didn't exist in a way we are used to in standard physics.</p>

<p>Nothing is really <em>known</em> (by empirical evidence) about this state, although there are theoretical approches (e.g. <a href="http://arxiv.org/pdf/gr-qc/9906072.pdf" rel="nofollow">this one</a>), which try to describe even those highly non-local and non-causal structures, from which "eventually" the Planck epoch could emerge.</p>

<p>The <a href="http://en.wikipedia.org/wiki/Planck_epoch" rel="nofollow">Planck epoch</a>, lasting from zero to about $10^{-43}\mbox{ s}$, the <a href="http://en.wikipedia.org/wiki/Planck_time" rel="nofollow">Planck time</a>, is still far from being understood, since the energy needed to fully investigate this state of the universe is far beyond accessible to experiments. We just know, that neither <a href="http://en.wikipedia.org/wiki/General_relativity" rel="nofollow">general relativity</a> nor <a href="http://en.wikipedia.org/wiki/Quantum_mechanics" rel="nofollow">quantum theory</a> describe this state correctly. Research about <a href="http://en.wikipedia.org/wiki/Quantum_gravity" rel="nofollow">quantum gravity</a> tries to fill this gap.</p>

<p>You may think of the pre-Planck and the Planck epoch as a state of the universe, which is dominated by <a href="http://en.wikipedia.org/wiki/Quantum_fluctuation" rel="nofollow">quantum fluctuations</a>. They don't need a reason or a cause to occur. They are a consequence of <a href="http://en.wikipedia.org/wiki/Uncertainty_principle" rel="nofollow">Heisenberg's uncertainty principle</a>.</p>

<p>As an example, if you try to measure time with very high precision, you'll get an increasing uncertainty in the energy measurement of the observed particle (<a href="http://ocw.usu.edu/physics/classical-mechanics/pdf_lectures/14.pdf" rel="nofollow">time-energy-uncertainty</a>). Within the very short Planck epoch, high energy fluctuations needed to occur, since both values (time and energy) cannot be pinned down together.</p>

<p>The reason for the Big Bang is thought to be such a kind of quantum fluctuations, yet not understood in very detail.
Questions like where?, when?, and why? don't apply in the intuitive sense to quantum phenomena. It's more a matter of probabilities, <a href="http://en.wikipedia.org/wiki/Schr%C3%B6dinger_equation" rel="nofollow">waves</a>, and relations between observable values, without the observable values themselves being defined independently.</p>

CC BY-SA 3.0
2014-05-02T12:54:31.030Z
2014-05-02T12:54:31.030Z
Gerald
<p>Given the vast infinite nature of universe, billions of worlds, distances and masses that we cannot comprehend, do you feel Big Bang theory is inadequate and in some ways tells you that it was all there from beginning.</p>

CC BY-SA 3.0
2014-05-03T03:10:38.280Z
What tells YOU that it was all there from the beginning as you say? What do you mean by distances and masses we cannot comprehend? The universe and it's general structure is pretty much well understood to  a certain degree.
harogaston
<big-bang-theory>
Big Bang Thoery, what triggered it and why
Jabran
# Big Bang Thoery, what triggered it and why

(Asked by: username_0 on 2014-05-02)

Given the vast infinite nature of universe, billions of worlds, distances and masses that we cannot comprehend, do you feel Big Bang theory is inadequate and in some ways tells you that it was all there from beginning.

**Tags:** big-bang-theory
> **Comments:**
> **username_1**: What tells YOU that it was all there from the beginning as you say? What do you mean by distances and masses we cannot comprehend? The universe and it's general structure is pretty much well understood to  a certain degree.  

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## 1 answers

### Answer by username_2 on 2014-05-02. Score: 3

Big Bang theory is rather adequate, with respect to observations. But it's incomplete. Your question is about the pre-planck epoch, a state of the universe, when space and time didn't exist in a way we are used to in standard physics.

Nothing is really *known* (by empirical evidence) about this state, although there are theoretical approches (e.g. [this one](http://arxiv.org/pdf/gr-qc/9906072.pdf)), which try to describe even those highly non-local and non-causal structures, from which "eventually" the Planck epoch could emerge.

The [Planck epoch](http://en.wikipedia.org/wiki/Planck_epoch), lasting from zero to about $10^{-43}\mbox{ s}$, the [Planck time](http://en.wikipedia.org/wiki/Planck_time), is still far from being understood, since the energy needed to fully investigate this state of the universe is far beyond accessible to experiments. We just know, that neither [general relativity](http://en.wikipedia.org/wiki/General_relativity) nor [quantum theory](http://en.wikipedia.org/wiki/Quantum_mechanics) describe this state correctly. Research about [quantum gravity](http://en.wikipedia.org/wiki/Quantum_gravity) tries to fill this gap.

You may think of the pre-Planck and the Planck epoch as a state of the universe, which is dominated by [quantum fluctuations](http://en.wikipedia.org/wiki/Quantum_fluctuation). They don't need a reason or a cause to occur. They are a consequence of [Heisenberg's uncertainty principle](http://en.wikipedia.org/wiki/Uncertainty_principle).

As an example, if you try to measure time with very high precision, you'll get an increasing uncertainty in the energy measurement of the observed particle ([time-energy-uncertainty](http://ocw.usu.edu/physics/classical-mechanics/pdf_lectures/14.pdf)). Within the very short Planck epoch, high energy fluctuations needed to occur, since both values (time and energy) cannot be pinned down together.

The reason for the Big Bang is thought to be such a kind of quantum fluctuations, yet not understood in very detail.
Questions like where?, when?, and why? don't apply in the intuitive sense to quantum phenomena. It's more a matter of probabilities, [waves](http://en.wikipedia.org/wiki/Schr%C3%B6dinger_equation), and relations between observable values, without the observable values themselves being defined independently.


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