Fermilab

At least some contemporary big bang theories begin with the entire universe packed into a very small, atom sized volume. Since black hole densities can be achieved by compressing the earth to the size of a marble; it seems that the early universe would have been dense enough to be a black hole and would have never expanded. Are the theories of the big bang and black holes at odds?

Thanks,
Doug McAllister
Tulsa

Hello Doug,

This is a good question. It is incorrect to think about the big bang as a highly compactified ball of matter exploding. Rather, the big bang was an explosion (really even the word explosion is not correct to use here since space itself was created during the big bang) of pure energy. At the moment of the big bang and for a short time to come afterward, there was only energy in the form of photons, which have no gravitational attraction to one another (they have zero mass). It was only sometime later, when the temperature began to decrease, that matter was able to form. This matter WAS (and still is) influenced by the gravitational force and clumped together to form the galaxies we see today. I hope that this answers your question. Please feel free to email me again if you would like further clarification or have another question.

Cheers,
Mike Clements
DZero Experiment, Fermilab

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