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Name: Kyler
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Question:
Everyone has heard the theory of the Big Bang, but I often ask myself, "If the Law of Conservation of Matter and Energy is correct, and has been proven it IS correct, then how come at the big bang theorized some 14 billion years ago all of a sudden out of nothing, a nothing just CREATE all the matter in the universe?" Wouldn't the law of Conservation of Matter and Energy and the Big Bang Theory just cancel each other out? How can the be? Only ONE of these is correct, and since the Law of Conservation is PROVEN true and is a law, and the Big Bang Theory is only a THEORY and not proven correct yet, than shouldn't the Big Bang Theory be confirmed as false?



Replies:
At the Big Bang and for several parts of a second afterwards, the physical laws of the Universe did not apply as they do now. For example, the Universe expanded faster that the speed of light in an event called "inflation" according to theory.

This is why some scientists are considering other origins of the Universe such as colliding membranes called "branes".

R. W. "Bob" Avakian
Instructor
B.S. Earth Sciences; M.S. Geophysics
Oklahoma State Univ. Inst. of Technology


Kyler,

First, no law of science has ever been proven to be true for all situations. So long as it seems to work well, to be useful, we keep using it. A theory that has been used in many subjects by many people is often called a law.

Second, the Big Bang is not necessarily from nothing. It might be from no matter, just energy. Energy can easily change into matter under appropriate conditions. If more than one universe exists, as has been proposed by superstring theory, it is even possible that the energy came from interaction with a parallel universe. In some models of the universe, it is even possible for energy to exist in the structure of empty space.

We do not know whether energy must always be conserved. So long as matter/energy conversion is allowed according to Albert Einstein's ideas, creation of energy from nothing has just never been measured. If such an event should be measured and repeated in many experiments, then we will adjust the Conservation of Energy and Matter "law" to allow for what is seen.

Dr. Ken Mellendorf
Physics Instructor
Illinois Central College


You have to be careful about the terms "Law" and "Theory" because in the scientific context their meaning is different that their everyday definition. Also "proven" is a very slippery term, because a mathematical "proof" and a "proof" in an experimental context are also very different. First, "only a theory" is not correct. A theory is the highest level of scientific certainty. It does not mean a "guess" or a "speculation". Second, "proven" in the mathematical sense means that the conclusions follow from the premises in a logical fashion. It may or may not have anything to do with physical reality. The mathematician cares less whether some theorem has any physical reality, only that the conclusions follow and obey the rules laid out by the mathematical system. This format is too short to go into much detail. However I would direct you to Richard Feynman's short, but elegant, book "The Character of Physical Law" explains the differences much better than I am able to do.

Vince Calder


I think your confusion might be the part where you say "out of nothing". The big bang describes rapid expansion of the universe from a highly (energy- and mass-) dense (and very small) state, not from "nothing". Thus, nothing about the big bang theory contracts mass/energy conservation.

I also would caution you against relying on statements like "is proven true and is law" -- all ideas in science are constantly subject to revision and challenge. As new evidence is presented, any idea may need revision. Whether an idea is labeled a "law", "hypothesis", or "theory", it may still end up wrong or incomplete. A great example are Newton's "Laws" of Motion -- which have been shown to be quite incomplete (enter relativity and quantum physics).

Naturally, you might ask about the origin of this very dense starting condition when the big bang began. There is a very short period of time that we cannot describe very well, called the Planck Epoch. If you extrapolate backwards from what we can model/describe, you might predict an infinitely dense singularity (zero volume) from which the universe began. However, we do not currently have models to describe such a thing. The best answer I have is that we just do not yet have the tools to model/explain this time period well.

Hope this helps,

Burr Zimmerman



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