- #1
raid517
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Hi, I know I'm probably going to get shot down in flames. I'm a total amateur to all of this. But I do try to read things and I do try to understand them - so I hope you guys will at least be patient with me.
But in any case I have been reading around about Noether's theorem and about the time invariant nature of general relativity. From what I can make out Noether's theorem appears to suggest (among other things) that the first law of thermodynamics agrees with Einstein's theory of General relativity in that it predicts that the first law can be considered as time invariant?
So this has led me to wonder somewhat if the first law of thermodynamics would apply equally well in reverse as it does when time is considered to be running forward?
I ask this because I wondered what would happen if you ran the entire process of the expansion of the Universe in reverse? Would the first law of the conservation of energy still hold - and if so what would it tell us? I wondered further what would happen if you ran the entire process back to the Planck epoch and perhaps even beyond? Would the first law continue to apply? (First let me make it clear that I am aware that it is not mathematically useful to try to describe events before the Plank epoch - I am merely curious as to what the first law of thermodynamics could imply if it were run back to that point?) I wondered this because I have a very hard job comprehending a Universe that could just have sprung into existence out of nothing.
So I pondered if perhaps the first law, due to it's time invariant nature (again I could be wrong on this) might actually be suggesting that even though we cannot know anything particularly useful beyond the Plank epoch, that everything that was needed to bring the Universe into being at time 0, was in some sense always already in place? I wondered if in fact the Universe did not have to emerge from nothing - because all it had to do was emerge from some previous 'pre-existing state?' (As is given by the statement that matter and energy cannot be created or destroyed, they can only converted). That is to say that although we cannot know anything useful beyond the Planck epoch, could we not say that whatever state existed prior to the this period merely had to be converted from one form into another in order to bring the Universe into being?
I suspect that I might be interpreting this rule too literally (as I usually do with such matters) and that there will be some special rule that would say that the first law of thermodynamics only applies up to a certain point. But as I said I am struggling to understand or come to terms with the idea that the Universe could ever really have had a beginning - because for me this implies a cause without an effect - which genuinely seems to me to be counter intuitive.
Also is it accurate to say that from our perspective the period of time leading prior to the Plank epoch leading up to time 0 would to us appear to last infinitely long? Thus implying perhaps that whatever existed before this period, could have existed for an infinitely long period of time? (Either this or the Universe would have needed to have always started out at a definite size - since before this period there would effectively be no measurable time). (I have some trouble with this concept too though, because it seems to suggest a universe that again spontaneously came into being out of nothing with a definite size - which in my own primitive imagination just does not seem plausible). Is the Planck time simply the shortest amount of time we are able to mathematically measure - even though some sense of something else may have existed beyond this time?
I know I am probably severely deluded, but really my ideal scenario would be a Universe that was born through natural and understandable laws and causes and which did not require that it was somehow just spontaneously brought into being - because in reality it had always existed - as had all of the rules and all of the material needed to bring it into being already in place.
So in other words, if the first law of thermodynamics can push our vision as far back as 10-43 seconds - why can't it push our vision even further back (if even purely through inference) to say that whatever state the universe existed in prior to the big bang - it still almost undoubtedly had a direct and real physical cause - or that indeed the universe was born through the conversion of one (unknowable) form of energy into another? Could the Universe in other words (through the first law of themodynamics) in some sense predict it's own birth?
Again I am sorry to trouble you guys with these dumb questions - but I do often find myself wondering about such things. I am often wrong and my musings are probably of not much significance to anyone other than myself - but I would just like to feel that I lived in a Universe that was at in some senses both definable and understandable - or that I could make at least some sense of.
Your input would therefore be greatly appreciated.
GJ
But in any case I have been reading around about Noether's theorem and about the time invariant nature of general relativity. From what I can make out Noether's theorem appears to suggest (among other things) that the first law of thermodynamics agrees with Einstein's theory of General relativity in that it predicts that the first law can be considered as time invariant?
So this has led me to wonder somewhat if the first law of thermodynamics would apply equally well in reverse as it does when time is considered to be running forward?
I ask this because I wondered what would happen if you ran the entire process of the expansion of the Universe in reverse? Would the first law of the conservation of energy still hold - and if so what would it tell us? I wondered further what would happen if you ran the entire process back to the Planck epoch and perhaps even beyond? Would the first law continue to apply? (First let me make it clear that I am aware that it is not mathematically useful to try to describe events before the Plank epoch - I am merely curious as to what the first law of thermodynamics could imply if it were run back to that point?) I wondered this because I have a very hard job comprehending a Universe that could just have sprung into existence out of nothing.
So I pondered if perhaps the first law, due to it's time invariant nature (again I could be wrong on this) might actually be suggesting that even though we cannot know anything particularly useful beyond the Plank epoch, that everything that was needed to bring the Universe into being at time 0, was in some sense always already in place? I wondered if in fact the Universe did not have to emerge from nothing - because all it had to do was emerge from some previous 'pre-existing state?' (As is given by the statement that matter and energy cannot be created or destroyed, they can only converted). That is to say that although we cannot know anything useful beyond the Planck epoch, could we not say that whatever state existed prior to the this period merely had to be converted from one form into another in order to bring the Universe into being?
I suspect that I might be interpreting this rule too literally (as I usually do with such matters) and that there will be some special rule that would say that the first law of thermodynamics only applies up to a certain point. But as I said I am struggling to understand or come to terms with the idea that the Universe could ever really have had a beginning - because for me this implies a cause without an effect - which genuinely seems to me to be counter intuitive.
Also is it accurate to say that from our perspective the period of time leading prior to the Plank epoch leading up to time 0 would to us appear to last infinitely long? Thus implying perhaps that whatever existed before this period, could have existed for an infinitely long period of time? (Either this or the Universe would have needed to have always started out at a definite size - since before this period there would effectively be no measurable time). (I have some trouble with this concept too though, because it seems to suggest a universe that again spontaneously came into being out of nothing with a definite size - which in my own primitive imagination just does not seem plausible). Is the Planck time simply the shortest amount of time we are able to mathematically measure - even though some sense of something else may have existed beyond this time?
I know I am probably severely deluded, but really my ideal scenario would be a Universe that was born through natural and understandable laws and causes and which did not require that it was somehow just spontaneously brought into being - because in reality it had always existed - as had all of the rules and all of the material needed to bring it into being already in place.
So in other words, if the first law of thermodynamics can push our vision as far back as 10-43 seconds - why can't it push our vision even further back (if even purely through inference) to say that whatever state the universe existed in prior to the big bang - it still almost undoubtedly had a direct and real physical cause - or that indeed the universe was born through the conversion of one (unknowable) form of energy into another? Could the Universe in other words (through the first law of themodynamics) in some sense predict it's own birth?
Again I am sorry to trouble you guys with these dumb questions - but I do often find myself wondering about such things. I am often wrong and my musings are probably of not much significance to anyone other than myself - but I would just like to feel that I lived in a Universe that was at in some senses both definable and understandable - or that I could make at least some sense of.
Your input would therefore be greatly appreciated.
GJ
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