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Conservation of Energy and Big Bang
Name: Kyler
Status: student
Age: N/A
Location: N/A
Country: N/A
Date: N/A
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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Update: June 2012
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