# Plank and the Big Bang

Discussion in 'Physics & Math' started by Greg Bernhardt, Oct 21, 2001.

1. ### Greg Bernhardtwww.physicsforums.comRegistered Senior Member

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201
Now the big bangs energy is supposed to equal Planck energy (10-31, right?). Then I heard that when the bang started to expand matter and anti-matter canceled out each other and the little that was left is our present universe. So is Planck's energy equal the mass of all matter at that point in time or all the combined energy of the present universe. If it equal the total energy of our present universe then Planck energy will never be harnessed because alot was lost during the bang from the anitmater collitions. what do you all think?

3. ### CrispGone 4everRegistered Senior Member

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1,339
Conservation of energy

Hi,

I'm not sure whether the Planck energy was the energy at the big bang, I believe the Planck energy is the energy level at which the four fundamental forces of nature unite.

When matter and antimatter annihilate, we assume in physics that energy is conserved (this is one of the most fundamental postulates). This means that the matter of the annihilating particles is converted to other forms of energy. For example, when an electron and a positron (=anti-electron) annihilate, you're left with two photons, light, and this is just another form of energy. So no energy was lost in the matter/antimatter annihilates after the big bang, it was merely converted into light.

The conservation of energy is based on the fact that the word "universe" includes everything (and I mean: everything). So no energy can dissappear from the universe, because the location or the form it went into would automatically belong to the universe.

Bye!

Crisp

5. ### HeveneRegistered Senior Member

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369
Since energy and are the same thing from E=mc^2, we can alway find a way to find all the energy. And Crisp mensioned the conservation of matter and energy, nothing is lost if we if the universe as a closed system. We could've viewed this as a smaller scale and then, eg. crashing of a car without regard to the entire system, then energy is not conserved.
Another way to explain this is to say that everything is trapped inside a potential well. Using Earth for example, nothing will escape Earth's gravitational pull. It is only zero as infinity and will require an infinate amount of energy for things to go beyond infinity. So nothing is lost.

7. ### fartimus GordonRegistered Member

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Big Bang

Oops! That wasn't a big bang that was just a humongous fart I just ripped.

8. ### HeveneRegistered Senior Member

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369
What ever that means...