#### marcus

Science Advisor

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the big bang has been studied by a number of people and found

not to contain a singularity

(the density does not go infinite but has a finite limit)

a good recent paper is

http://arxiv.org/gr-qc/0407074 [Broken]

Genericity of the Big Bounce in isotropic loop quantum cosmology'

Date and Hossain

they calculate, among other things, the maximum energy density that occurred right at the crossover between contraction and the onset of expansion

you can guess

the energy density at the onset of expansion is bounded (Date and Hossain argue) by our old friend the planck energy density!

So we can say, in joules per cubic meter, what is

or if you prefer in kilograms per cubic meter---with the understanding that it is kilograms of mass-energy---using mass to measure equivalent energy content

We can figure it out----the planck energy unit is 2 GJ------2E9 joules

and the planck unit volume is 4.2E-105 cubic meter

So just divide and it comes out around

4.6E113 joules per cubic meter.

divide by c

i guess that means divide be 9E16

planck unit energy density may seem useless because so huge

but it is actually an OK unit and its nice to know that it was back there

at the bounce and so-to-say participated in bringing us into being

and there it is: 4.6 x 10

not to contain a singularity

(the density does not go infinite but has a finite limit)

a good recent paper is

http://arxiv.org/gr-qc/0407074 [Broken]

Genericity of the Big Bounce in isotropic loop quantum cosmology'

Date and Hossain

they calculate, among other things, the maximum energy density that occurred right at the crossover between contraction and the onset of expansion

you can guess

the energy density at the onset of expansion is bounded (Date and Hossain argue) by our old friend the planck energy density!

So we can say, in joules per cubic meter, what is

**the mother of all energy densities**.or if you prefer in kilograms per cubic meter---with the understanding that it is kilograms of mass-energy---using mass to measure equivalent energy content

We can figure it out----the planck energy unit is 2 GJ------2E9 joules

and the planck unit volume is 4.2E-105 cubic meter

So just divide and it comes out around

4.6E113 joules per cubic meter.

divide by c

^{2}if you want kilograms per cubic meteri guess that means divide be 9E16

planck unit energy density may seem useless because so huge

but it is actually an OK unit and its nice to know that it was back there

at the bounce and so-to-say participated in bringing us into being

and there it is: 4.6 x 10

^{113}joules per cubic meter
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