Laws of Conservation?

I have a basic understanding of the law of conservation of energy. It pretty much says that something can't come from nothing. If you think back to the very beginning of things wouldn't there be a time where nothing existed? If there was a time when nothing existed then how does anything exist today? Doesn't the "existence" of "things" today violate the law of conservation of energy, because in the beginning nothing existed?

Thread moved here from the Proposed New Topics forum.

This is very much a popularist view of conservation of energy, and has little to nothing to do with the actual physics/mathematics. Conservation of energy is simply a statement of *local* continuity, and does not necessarily imply a large-scale conservation (large-scale meaning on the scale of the Universe itself) The obvious example of global breaking of energy conservation is a worm-hole time-machine, where a traveller meets himself exiting a wormhole - he travels with himself to the other worm-hole entrance, where he takes leave of his future self and enters the worm-hole that leads him back to the point in the past, where he exits the wormhole and meets his earlier self. Here, energy conservation is very much violated as we start with one traveller, then have two copies (or three, if we count the wormhole tube as well) and then we are back to just one. Nothing is a meaningless concept - if there is time, there is something - time at the very least. So you cannot point to a time where 'nothing' exists. There is no moment when there is nothing and then a moment when there is something. This is nonsense. There are only moments where there is something, for moments themselves are 'something'. It is quite possible that the Universe has an earliest time - but this does not represent a beginning to the Universe - just a beginning to our idea of time. Just as the North Pole is the beginning of the lines of longitude, but it is not a beginning of the Earth.

Don't these two propositions contradict one another?

If my decription of time-travel was confusing, here's a diagram to help:

^
             ^
C .......    ^
             ^
             ^
             ^
             ^            ________________
             ^           |                |
             ^           |  >>>>>>>>>>>>  |
             ^           | ^  ________  v |
             ^           | ^ |        | v |
             ^          /  ^  \       | v |
             ^            ^           | v |
             ^           ^            | v |
             ^          ^             | v |
             ^         ^              | v |
             ^        ^               | v |
             ^       ^                | v |
             ^      ^                 | v |
             ^     ^                  | v |
             ^    ^                   | v |
             ^    ^                   | v |
             ^    ^                   | v |
             ^    ^                   | v |
             ^    ^                   | v |
             ^    ^                   | v |
B .......    ^    ^                   | v |
             ^    ^                   | v |
             ^    ^                   | v |
             ^    ^                   | v |
             ^    ^                   | v |
              ^  ^                    | v |
               ^^                     | v |
               ^^                     | v |
              ^  ^                    | v |
             ^    ^                   | v |
             ^     ^                  | v |
             ^      ^                 | v |
             ^       ^                | v |
             ^        ^               | v |
             ^         ^              | v |
             ^          ^             | v |
             ^           ^            | v |
             ^            ^           | v |
             ^          \  ^  /       | v |
             ^           | ^ |________| v |
             ^           | ^            v |
             ^           |  <<<<<<<<<<<<  |
             ^           |________________|
             ^
             ^
A .......    ^
             ^
             ^                  ^ Time
             ^                  |
             ^                  |
             ^                  |
             ^                  |
             ^                  -----> Space
             ^
             ^

If we look at the Universe at time A, our traveller contributes once to the total energy. But at time B, he contributes twice, or three times, if we add in his contribution from the wormhole. Then, at C, we are back to a single contribution. So much for conservation of energy Note, however, that other 'fundemental' conservation laws can be said to hold as long as we account for the time-reversal of the wormhole. So, for example, Baryon number for our traveller is B + B + (-B) = B.

Besides the point that cavediver made, I will point out that even in classical physics, the Law of Conservation of Energy states simply that at any two different times, the total energy content of a closed system will be the same. In the case of the universe, there was no time when the universe did not exist -- there was no "before" the universe since there was no "time." So, no, energy conservation was never violated since there was never a time when the total energy content was different. (That's not taking into account the correct GR description of the universe that cavediver is providing.)I will also point out that the so-called Laws of Physics are merely summaries of patterns that we have observed so far. The Laws of Physics have changed quite often in the history of science when new phenomena were observed to violate what was understood to be the Laws of Physics. It was believed, for example, that there was a Law of Conservation of Matter until nuclear processes were discovered and understood.So, correctly speaking, the Law of Conservation of Energy simply means that we have never, so far, observed the total energy content of a closed system change. But maybe it does change in some situations -- like during creations of universes, which no one has ever observed.

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Speaking personally, I find few things more awesome than contemplating this vast and majestic process of evolution, the ebb and flow of successive biotas through geological time. Creationists and others who cannot for ideological or religious reasons accept the fact of evolution miss out a great deal, and are left with a claustrophobic little universe in which nothing happens and nothing changes.
-- M. Alan Kazlev

I highly recommend the book The Man Who Folded Himself by David Gerrold. His best known work is probably the The Trouble With Tribbles script for the original Star Trek.--Percy

I've not read it but I know of Gerrold himself, and I know it's based on "inconsistent" time-travel. I'm happy reading about it as fiction, but I'm always desperate for good fiction with "consistent" time-travel (as depicted in my diagram and description above) - The Lost script writers are making a good go of it at the moment, though they do slip every now and again, both intentionally and unintentionally. The "circular" compass that Richard passed to Locke and passed back again is a common problematic issue - but I had an epiphany last night regarding the numbers, which I thought both wonderful and very fitting with my own views of reality. Let's see if the writers are on the same wavelength Perhaps a time-travel thread is needed?

I don't get this. It seems to imply that mass/energy is required for time to exist. Could someone explain it or give me some links?

Try to look at it like this: What is north of the north pole?That's the same question as asking: What happened before the big bang?Get it?

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I hunt for the truth

Time is a part of the universe, itself, not something that the universe exists within. Time doesn't exist if the universe doesn't exist.

Thanks, I guess I was just thinking of the big bang as the source of matter in the universe and not time as well. So my question now is why do we assume the big bang created time. In other words is time a function of matter and energy or could there be some other type of universe with a whole bunch of time but no matter or energy.

Time is an integral part of the universe. Without time, there is no universe. Without space, there is also no universe. Without matter, there is nothing inside the universe.

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I hunt for the truth

Yeah, that's incorrect. Its not an assumptions, it a conclusion. And it comes from general relativity. Time is a dimension of the universe. Just like up-down, left-right, forward-backwards are all spatial dimension, time too is a dimension (but not a spatial one). Matter and energy exist within the dimensions so questions about them vs. time don't make much sense.You could look at the wiki page on spacetime for plenty of stuff to read and learn about.Have fun with it.

Yea! That's what I was looking for. Thanks