What is time and why does it exist?
 

Any ideas?
For example, I know how our bodies get old, but why should they do so in the first place?
What is time?
Why does it even exist?

There seem to be two different ideas in your post, one about Time, and another about Aging.

Aging, I am sure, has something to do with our biology. Although I have heard that scientists aren't completely clear on why it happens. So I don't know.

Time, I'm sure a physicist would be able to explain better, but I see it as a fourth (or whatever) dimension.

Ageing happens because cells decay over time as they deplete their energy stores. When they deplete faster than they can be regenerated, ageing occurs over time until eventual death. We are living longer nowadays because of scientific advances to reduce cell death and fight infection. Ageing is still inevitable though.

Time is a human construct. We created it to make sense of our world and allow advancement and social constructs to develop.

I would disagree with that. To an extent, yes (as in our dividing of time into hours, minutes, seconds), but even if we were to not count it, time still happens. Today becomes tomorrow, centuries go by, all regardless of our counting it.

Things change on a continuum, yes, But if we hadn't developed methods of quantifying that change we wouldn't have days, or years or centuries. We gave periods of change a name. The earth rotates and we used the passing of the sun and moon to develop a name for that passage of change (and called it time).

Time only happens in the form we know of because we called it so. If we didn't have the intellect to develop a system of using referential changes to denote the changing of time then it just wouldn't exists. A year wouldn't exist fi we didn't quantify it. It's not 'there' without us. The seasons are. But that wasn't a year in and of itself until humans imposed time names upon it.

I do see what you're saying. But giving something a name doesn't necessarily make something exist where something didn't exist beforehand. We gave a name to something because we noticed that it exists, the name only has descriptive value.

There is an episode of Horizon presented by Brian Cox called "time" and it's really interesting. It explores the question "what time is it."

Time is pretty subjective. The Mayans recorded it differently from the way we do, for example. Atomic time is the most accurate way of measuring time and is used in GPS and satellites.

Our days are also getting longer by about a minute every few thousand years (might be million, but it was a long time anyway)

Time happens because without it everything would happen all at once and that would be really confusing,
or alternatively nothing would happen as changes take time and without time nothing could change

so time exists to separate and allow things to happen and allow an observer to recognise that things happened

^No, things would happen anyway. If we didn't have the hours on a clock, the sun would still rise and set. We created time to make sense of the events around us. Not to make sure they happen.

But if we didn't have the concept of time then our physics would make no sense at all....

I disagree. Of course things would still happen, why wouldn't they? Before humans, and before life at all the sun still rose and fell, the Earth still spun and things kept moving forward but there wasn't Time.

I was talking about what we call time not how we measure it, we created a way of measuring something we see, and called what we saw time, then split it into useful units and all that (or maybe we named it before working out how to measure it). Yes if we didn't measure time it would keep going.

The same question could be asked what is distance, and why does it exist?
And the 3rd follow on (because I'm in that kind of mood) if time or distance don't exist how does anything move?

Going with time as a 4th dimension, time moves at a rate in a fixed direction (both fixed for the sake of argument - yes time dilation can slow time for objects/people travelling at high velocities, and so far we've not reversed it or knowingly travelled back), we know that in 1s we move so far along this dimensional axis
Now imagine a grid in 4dimensional space, you have a point lets set it at 0,0,0,0 for the sake of simplicity, then move that point to 1,1,1 in 1s it will be at 1,1,1,1
Now if time doesn't exist, the point in 4d space would be at 1,1,1,0 - actually 1,1,1 because the 4th dimension isn't there - simultaneously in 2 places at once, but it also couldn't have moved because that took time so its still at 0,0,0

So going back to what I said earlier, without time either nothing could happen or it would all happen at once.

Without us measuring time, then time or whatever we want to call it still happens. With no concept of time, we might know day and night happen but never know that one follows the other, without measuring time we wouldn't have tracked the suns movement across the daytime sky, and the stars across the night. We really wouldn't have gotten far, navigation from the sun or stars would never work, and night time hunters would have found us easy prey all lost in the dark after we didn't connect the sun setting with incoming darkness and plan the time to seek shelter.

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Maybe a bit much for 11pm on a sunday night that

TL;DR, its not that I disagree with what you both are saying, its that I was talking about time itself, not our perception and measurement of it.

"Time" as a human construct of measuring it didn't exist, but what I'm arguing that the rising and falling of the sun, that happens on a particular dimension or continuum regardless of humans giving it a name, which is what I am referring to as "Time".

So, seeing as there appear to be two separate things we can mean by "time", I am interested whether the OP is going to come back and comment on this, and maybe say which of the two (or more) constructs we're actually discussing.

The current definition of time is based on the changes of a cesium atom and has nothing to do with the movement of the earth. For most of us moving at a small fraction of the speed of light, time can be considered constant, eg 2 people being born at 10am at different hospitals could be said to have been born at the same time.

its useful in day to day life now because people need to get to appointments, go to work etc
i mean, nowadays, if there were no appoinment times, a gp waiting room would be chaos.

i know, not as techincal or intelligent an answer as most people here, but it is 3am....

Sorry, I should have made myself clearer. I meant time NOT as a human construct. I agree that we give things names to try and make sense of them but I want to know why things have to follow on from each other in the way they do.

Brian Cox was talking about the future. We always talk about looking to the future, like it is something that is going to happen next.

It's actually happening now. The present and the future are happening simultaneously. It's like driving to the sea. The sea doesn't start when you get there. It's already there, and you get to it. Or like driving on a long road looking at the horizon. The horizon is already there, and so is the little garage in the distance. It's already there even until you get to it.

That's one theory, any way.

I will need more time to think about it, but here are some of my initial thoughts:

1. What happened before anything in the universe existed? Where was time then? I would say that it did not exist, and perhaps it still does not exist. Time as a concept is a human construct, presumed to be universal, to indicate change. If something does not physically change then it either must be outside of time and/or indicate that time is not a universal law of the universe.
2. Time is relative. I haven't given any time researching the way that time and space bends under pressure/ gravity, but supposedly it does.
3. Technology presents an interesting new way in which time is distorted. Decades ago it took much longer to communicate and travel across the world. In the 21st century, technology and the internet are in essence shortening distance and time. Communication with people many thousands of miles from me is possible thanks to this very forum. Threats of terror and war and suddenly much closer (mostly in distance but also time-wise). So we see how technology can, too, make time a relative concept.


I'm going to digress a little, but I wanted to make a brief comment on your analogy of the future being a "garage in the distance", Control Freak. I would have to disagree with you there. I believe that the future is a place unforeseeable until the very end (death). Every moment of our lives we are changing. Because of this our past too changes (so one could say that the idea of "one's past" doesn't exist because it is always in motion). The only thing that exists is the present, and the present way that we perceive ourselves. The past is absorbed into the present, and there is really no such thing as the future. The garage represents not the future but the finality of the present.

Just my two cents. :)

Asura, I might come back to think about your other points a bit later, but in terms of your third point, you propose that technology makes time a relative concept. From the example you describe, I would argue that it is distance that has become relative, rather than time, because of technology (both communications technology and transport).

Okie dokie. If I overlooked something please critique my analysis. Like I said, I haven't given it much thought.

I agree that it's more so a shrinkage of distance, but I still think that with distance comes time. News travels instantaneously across the globe now.
1. Decades ago one would have to wait days, maybe weeks, for a letter.
2. In the past, if one wanted to research something, they needed to locate an encyclopaedia and sort through it. Through computers I can do the same in a few seconds by looking on wikipedia.
3. How about spy games. As early as World War 1 spies were beginning to be used by state governments. It was immensely easier to pass as a spy then because word travelled at a slower rate. Nowadays there are databases, instant phone calls and connections of phone lines to anywhere. For the spy, the shrinkage of time is also problematic.

I can see how these examples might exemplify "how technology has changed the world" rather than "how technology shrinks time". But I believe the latter is there. Sorry I don't think I can explain it any better, lol.