I fail to see the difference between Alive’s reasoning and my number line analogy. They seem exactly as strong as weak or each other to me.
Expano, I take your point. I’m not arguing whether or not the universe is infinite in time or space, or any transistion, I just don’t buy (or maybe understand) Alive’s reasoning for why it couldn’t be infinite.
Just so I’m clear, this implies that there has to be an end to time as well, correct? Does it mean that there necessarily has to be a Big Crunch awaiting us?
I disagree. The present is an arbitrary point on a continuum that is infinite in both directions. Time does not come to an end simply because we mark an arbitrary point.
It is not a contradiction, because time does not end at the arbitrary point we have designated as the ‘present’.
Best guess today is there is no Big Crunch in awaiting us in the future. Recent measurements suggest the Universe will expand forever. Eventually all the other galaxies will be receding from us at over light speed and ours will seemingly be alone in the Universe. Eventually all the stars will wink out and everything will evaporate into space basically smearing out an atom here and an atom there which will cool ever closer to absolute zero. There will be no energy available to do any work whatsoever. In short, the Universe will end with a whimper instead of a bang.
It should be noted that in these questions of “what came before” you can continue to ask the question ad nauseum. You can even apply it to a God if you wish. While a “before the Big Bang” may have no meaning to us even if there was a before we are on the road to an infinite sequence.
Not necessarily. No matter how far you travel in the future, it is a finite amount, and the universe will be of finite size. This holds even if you travel past the time of photon decay. But, there will never be a time when nothing happens, because of quantum fluctuations. There will also always be energy, though with total entropy nothing can happen.
I read an interesting kind of analogy in a book on quantum gravity. Imagine a situation where there was only one point of matter. In that universe, space does not exist, since space is only measured between points of matter. (I say point to indicate the “matter” has no dimensions.) That is hard to get your head around, but maybe easier than the no time situation.
I fail to see the problem. Actually, I don’t understand why “an end” has anything to do with this issue.
Indeed, if time extend infinitely before the beginning of the universe (be it the big bang or the fiat lux), the beginning of the universe will never happen, since we’ll always have to wait an infinite time for this moment to come. After 10 billions of billions of billions of years, the big bang will still be infinitely distant in the future.
Actually, it seems to me it’s same with integers. We could spend an infinite time counting integers, and we would never reach “0”.
Except of course if we count time or integers beginning at a given time (or given integer), but then, it’s just arbitrarily fixing an origin of time different from the big bang, so the problem stays the same.
The answer to your question can be found in a book located one mile north of the North Pole.
Name a number and I’ll name one lower.
In answer to the question of why it happened, I offer the modest proposal that our Universe is simply one of those things which happen from time to time.
–Edward P. Tryon
I understand. But if there is no upper bound to how far you can travel in the future (cold and dull though that future may be), if “t” never stops increasing, how is it wrong to say that the expected life of the universe is infinite?
(Note that you and Whack-A-Mole both use terms such as “always” and “forever.” 
)
BTW, I’m not challenging you, I’m just trying to refine my thinking.
How do you want this question answered? Scientifically, our best theories for the origin of the Universe cannot incorporate the concept of a time before the Big Bang. And you specify in the OP that you want to leave theology out of this. I’m at a loss coming up with any other framework for discussing cosmology, other than science or theology.
Assuming there is no mechanism that will somehow recycle this Universe (or just end it in some fashion) then when you say the Universe is infinite you are saying there is no eventual end.
However at any given moment, be it now or a bazillion zillion years in the future, the Universe is finite in size at that moment. It may be really, REALLY big but still finite.
The set of integers may be infinite but as you count there is always a “now”. No matter where you are in your counting you have only listed a finite number of integers. It is only infinite in that you can count forever.
Actually ( but arguably ) the universe has very close to zero energy. The energy of everything in the universe is almost completely offset by an equal negative gravitational potential energy.
Well, I have a theological answer I’m happy with and this isn’t the forum for it anyway.
The big bang is an event. I guess I cannot begin to believe that an event can occur without a precursor. The vacuum flux theory is the precursor to the bang, but that implies that there was just nothing here before, nothing but virtual-particle filled vacuum.
The massive-black-hole-in-another-universe still has the same origin problem, it just moves it over there.
The bouncing universes just create another line of infinities which has no origin again.
It seems that the cosmologists have no freakin’ idea but they don’t want to admit that.
There also seems to be a worry to be pondered here. If universes can just pop out of nowhere due to spontaneous virtual particle interactions, then we should be seeing little bubble universes popping up. If they’re inversely more likely with decreasing energy, them mini-big bangs ought to be happening around the observable universe all the time.
Is there any evidence for this?
I think it’s fairly obvious that the universe does not, in fact, exist.
Um, actually they all freely admit that.
This from Bobo the “Optimist”? Clearly this is Bobo’s evil twin from a mirror universe.
Which also does not exist.
That’s good news. Now I won’t have to mow the lawn.
Go visit that GD thread where I suggest that a deity was involved, though, and there’s 100 reason’s why that’s impossible but it seems nobody can provide a scientific alternate…
That’s why I brought it over here - trying to find out answers that don’t involve God. Instead it seems I just find a different dogma.
You’re being too harsh. “I don’t know” does not strike me as dogma.
That is going to make it difficult if all the data points to that.
Why the fixation on an origin? Personally, I find the concept of an infinitely old, infinitely recreated universe much more plausible than a finite origin that prompts all sorts of unanswerable questions. And if you believe in an origin, it seems like wondering about what came before sort of defeats the purpose. If there is a finite origin, that cannot be a ‘before’ as that would invalidate that event as an origin. Doesn’t the concept of an origin, by definition, imply there is no before?