Infinite time?

[charris]

It seems to me possible that there is an infinite time, specifically that of the past. All that would be required is for a previous event or cause (depending on you interpretation of QM).

I mentioned this, and was met with the objection, "If the past was infinite, then it would have taken an infinite amount of time to get here." I personally think this objection is pointless, so maybe if you think this is the case you could expound upon it. If you disagree, then if you could post your reasons as well I would appreciate it.

Also, if you disagree because of other reasons, I would like to hear them.

[McCulloch]

My current understanding is that spacetime is finite. And that due to relativity, that if time were infinite then space must also be.

[LiamOS]

Given the predictions of General Relativity and the standard model of cosmology, I'm not entirely sure that positing an infinite past is either reasonable or relevant.

Could you expand on your reasons for this position?

[charris]

I can certainly explain my reasons: ignorance. I honestly don't know if it even makes logical sense to say that time is infinite, it just seems to make the more sense than time having not existed (to me). While, from what we know from cosmology, our universe is finite, I had asked the professor of theoretical physics at CalTech whether it is possible that something like quantum fields etc. could have existed for eternity, and he said that we don't know but it's plausible.

I should clarify my original question: I'm not talking about our universe's time. If time is present in quantum events, which I would think it would at least to an extent, then time could have existed forever. The time in these quantum fields would be much different than ours. (After all, time is just repetition in events, in our case seconds.) I guess another way I could ask this would be, Were there always events going on, if only at the quantum level?

[McCulloch]

I'm not talking about our universe's time.

I don't know about any other time. Time (and space) are part of the fabric of the universe. Outside of the universe, we can only speculate.

[Grumpy]

charris

Even if time will go on forever(therefore infinite)it had a beginning and a finite amount of time has passed since then. This will always be true. So, time is infinite in nature, but finite at any one point(moment)in time. The concept of infinity is a figment of our intellect, our expectations, not a description of reality.

Second, time is a dimension just as space has three. Physicists refer to the space/time continuum because it takes all four dimensions to describe the now(the present), all of the previous nows(the past)and all of the coming nows(the future). Infinities do not exist in the past, it is both a finite amount of time from the beginning(the Big Bang)and from the present. It has also been a finite amount of time to the present. Only in the future can we envision(conceive of)an infinity, and the future does not now, nor has it in the past(all the other nows that have occurred)exist(ed).

Grumpy

[charris]

I'm not talking about our universe's time.

I don't know about any other time. Time (and space) are part of the fabric of the universe. Outside of the universe, we can only speculate.

That's what I'm asking you guys to do; to speculate. Time would still be present in quantum fields, if I'm not mistaken.

Even if time will go on forever(therefore infinite)it had a beginning and a finite amount of time has passed since then. This will always be true. So, time is infinite in nature, but finite at any one point(moment)in time. The concept of infinity is a figment of our intellect, our expectations, not a description of reality.

So basically, what you're saying is that time in our universe, for example, is finite, but there is still time before that? Because infinite in time would mean there is no beginning.

Second, time is a dimension just as space has three. Physicists refer to the space/time continuum because it takes all four dimensions to describe the now(the present), all of the previous nows(the past)and all of the coming nows(the future). Infinities do not exist in the past, it is both a finite amount of time from the beginning(the Big Bang)and from the present. It has also been a finite amount of time to the present. Only in the future can we envision(conceive of)an infinity, and the future does not now, nor has it in the past(all the other nows that have occurred)exist(ed).

Yes, time absolutely is a dimension. But we don't know if spacetime began at the BB or not. Our current laws of physics break down before we get 'there'. What I'm asking is if something like a quantum field could have existed for eternity, thus allowing (at least our) universe(s) to begin. The universe wouldn't be infinite, the quantum field would be.

[Grumpy]

charris

So basically, what you're saying is that time in our universe, for example, is finite, but there is still time before that? Because infinite in time would mean there is no beginning.

Well, time had a beginning, our physical sciences are able to tell us that. There are places in our Universe where time slows to a stop, the event horizon of a black hole is one of them. The speed of light for any mass is another. The closer you get to either, the slower time passes(from the rest of the Universe's perspective, it's all Relative).

But infinity is not limited by having a beginning. While we know that time had a beginning, we do not know if it will ever have an end for the Universe as a whole, it stretches infinitely into the future. But infinity is a CONCEPT, not a thing that actually exists or has ever existed, it also has no possibility to exist in the future. At every point in the future it will be a finite amount of time to the beginning(and between then and any other past) and an infinite amount of time to the end of time. Define that infinity any way you want. If our Universe had been a bit heavier we could probably tell you when time will end in the Big Crunch, but it appears that will not happen. If it is our fate(as matter)to end up within the Event Horizon of the Supermassive BH at the heart of our galaxy, then that will be the end of time for us.

Grumpy

[Coldfire]

It seems to me possible that there is an infinite time, specifically that of the past. All that would be required is for a previous event or cause (depending on you interpretation of QM).

I mentioned this, and was met with the objection, "If the past was infinite, then it would have taken an infinite amount of time to get here." I personally think this objection is pointless, so maybe if you think this is the case you could expound upon it. If you disagree, then if you could post your reasons as well I would appreciate it.

Also, if you disagree because of other reasons, I would like to hear them.

Time is infinite, there is no beginning nor end. We mark points in time as the beginning and end of certain events, however that doesn’t mean that time started at that point. The statement “if the past was infinite, then it would have taken an infinite amount of time to get here,� is strangely true, but it doesn’t necessarily disprove time being infinite. Human existence or even the existence of the universe may have begun at a certain point of time, but it doesn’t mark the beginning of all time. There is no such thing.

Time is not existent in itself, it is simply a measurement of past, present and future nows. There is no measurement of time because time is the measurement. You cannot define a word by saying “happiness means happiness� and you cannot measure "time" by using time because there really isnt a "time" to measure. It is infinite, ever going, not ending and not beginning.

Some people will describe ininite as a circle or figure eight. This can be true, but it doesnt exclude the idea that it could be a straight line withought a beginning or end.

[McCulloch]

Coldfire, how is it that you have come to the conclusion that time is infinite?

Time is a part of the measuring system used to sequence events, to compare the durations of events and the intervals between them, and to quantify rates of change such as the motions of objects. Without events or objects that could change, there could be no time. Time would be meaningless. Einstein wrote in his book, Relativity, that simultaneity is also relative, i.e., two events that appear simultaneous to an observer in a particular inertial reference frame need not be judged as simultaneous by a second observer in a different inertial frame of reference. The concept of time depends on the spatial reference frame of the observer. Thus, if relativity is true, if time is infinite then space must also be.