This question is prompted by this one: http://answers.yahoo.com/question/index?qid=20080113145242AA9II0m&r=w&pa=FZptHWf.BGRX3OFPgTRXVh8xZfoD8Am3b7SlvjfuNBoeFT1r.w--&paid=answered#E75rB1L6D2s_z_gndsZg which is why I'm posting it in this forum.
No, I'm not trying to be a smart @ss. I really want to know, because the nature of time vs. eternity is not something I remember learning about in physics.
So, then...
If time itself is eternal, how is the big bang occurring within eternity different than Java Junkie's question where he asserts that nothing eternal can ever change or cause change? Am I missing something here?
And if time is not eternal, what came before it?
2008-01-13T15:29:50Z
If time is relative, an illusion, and only exists in this world (universe, I assume), then what does science say exists outside of it?
Anonymous2008-01-13T20:59:22Z
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First of all you have to realize that time is a physical quality and quantity.
If you take one second and divide in half it equals half a second and divide that in half again equals quarter of a second but if you keep doing it there reaches a point where time can no longer be divided in half anymore.
Real Time began at the point of the BIG BANG but what existed before then is anyone's guess. For anything to happen there has to be time but something did happen or was happening at the time prior to the BIG BANG but exactly what that might be, nobody knows.
It has been said there's another aspect to time called 'Imaginary Time' and this is what physicists might be able to use in order to work other things out where and when 'Real Time' didn't actually exist.
I will give you the same answer as I gave the other questioner.
The general human Idea of Time is not eternal, I say general because there some who think differently than most westerners, If we take the Hindu's for example the concept of the universe gets pity close. If you don't know there story here's a basic outline.
Vishnu awoke from his sleep within the endless coils of a giant cobra floating on the waters of nothingness and a magnificent lotus flower grew from Vishnu's navel in which was Brahma his servant who he then ordered to create the world. They give this beginning a date of 77.76 trillion years Before Present Day, though this maybe due to the fact that they seem to believe in a cyclic universe which has times when the universe takes form and times when it dissolves back into nothing. This is not so different from a counter theory to the big bang, or maybe I should say continues it, in which the universe behaves like a never ending applause.
77.76 trillion years is a lot closer to infinity than the 15 billion years of the the Big Bang Theory and the 6000 years or so of Creationism.
When one gets into thinking outside our concepts of time we generally get into trouble as eternity is just to big! With infinite time comes infinite possibility.
As for 'nothing eternal can change or cause change' This has no grounding and it the flaw in his logic. Though if one were to look at the true Cosmos (all that exist inside and outside of our perceived universe, and watch it for all eternity, Though this would be impossible by it's very definition, There would seem to be no real change, however in local subjective areas change would be happen at such a fast rate that unless slow down to the speed of our minds we would not notice it.
There seems to be no end to the universe, and it can be assumed from that, that there is no beginning. If you were suspended at some point anywhere in space you would in effect be at the centre of an infinite void. The question of what lies beyond the universe has no bearing since if you think of the concept of a "brick wall", one could argue what lies beyond the brick wall. The same can be said of time.
Einstein s theories are well proven to show light as the "cosmic speed limit" and time dilation being evident to all observers no matter where they are in the universe. Therefore it is logical to assume that time itself is also infinite and has always been and always will be eternal. It is only our consciousness that is aware of time passing.
If we were not here in this physical form to observe the universe in all it s glory, how would we know it exists? There was however a Big Bang but it did not emanate from a single point. It appeared everywhere simultaneously as can be verified by the microwave background radiation. This only applies to matter within the universe itself, although there is no doubt that all matter and space-time are remarkably interweaved. It should follow therefore that our consciousness too must also be of an eternal nature, since we are not separate from the constructs of the universe we abide in.
First - time is not an illusion in that it is as real as energy, matter, dimension. Without dimensions everything would need to exist in one space - a singularity.
Time - is necessary for motion (also a dimension) without time everything would happen all at once - or not at all.
No. Time is no eternal. It began with the Big Bang and it will end with the ending of our Universe. However, it is also suggested that time becomes infinite within a black hole. How this is resolved within a finite Universe I don't know.
Neither do we know what happened before the Big Bang nor how our Universe will end. The Big Crunch seems not a likelihood anymore.