New edgy thread

im confused, to me, unbounded means without boundaries, which is the same as infinite. so what i read that as is... infinite and finite or infinite and infinite.

can you clear this up for me please?

Why certainly young man.

Unbounded does, as you say, mean without boundaries, but it is not the same as infinite.

The key to understanding the universe in these terms is to initially abandon commonsense ideas about geometry.

When we muck about with geometry on a piece of paper (standard Euclidean geometry) everything works nicely, 3 corners of a triangle add up to 180° and there is only one definition of a straight line that will pass between two fixed points - basically everything is 'normal', everything is commonsensical, easily understood. For example if I walk ten miles South, then ten miles West, the ten miles North - I end up in a position exactly ten miles West of my starting point.

When we apply the same measurements to - for instance - the surface of a sphere, things fall apart - using the same walking pattern as above - you start at the North pole, walk ten miles South, ten miles west and then ten miles North - but you do not end up ten miles to the West of where you started (like in the above example), you actually end up in the exact same position as where you started.

This is because Elucidian (standard/normal/commonsensical) geometry does not apply to a sphere, you need to use a non-Elucidian geometry (in this case we would need to use spherical geometry).

Similarly when we further abandon the world of 2D (the surface of a 3D sphere is a 2D surface) and move out into the universe our non-Elucidian spherical geometry falls apart - we need to employ hyperbolic geometry, and if you thought non-elucidian geometry was fucking weird, then this stuff is bad ass.

Let's look at the easy one first (easy because it does not breach our commonsensical understanding of geometry) - unbounded and infinite.

This is fairly easy to grasp in simple terms, spatial dimensions continue unbounded in all directions, the further you travel in one direction the further you are removed from your starting point.

Now onto higher dimensional analogs ! :s Unbounded and finite - this is the currently accepted model, the universe is finite in spatial dimensions but unbounded.

So how to explain finite but unbounded. Let's imagine a giant sphere, it's surface is a 2D surface, now imagine a tiny 2D being exploring the 2D surface of this giant sphere, regardless of how far it travels it will never meet a boundary, it can keep exploring in any direction forever and never meet a boundary - it's 2D world is finite in size, yet unbounded.

Now extrapolate this 2D model into 3D and (very crudely put) you have a starting point for understanding a finite/unbounded universe. You can travel in one direction in a straight line for a few billion years, never meet a boundary and then arrive exactly where you started, in this respect space is curved.

Well . . . I am not sure a 'straight line' can exist in curved space (?) but what I am trying to say is that the reason you end up where you started is not because your trajectory is slightly off course it is that the universe in shaped to bring you back to where you started.

oh and do you mean infinite as in goes on forever in terms of distance, or infinite in terms of will exist forever - i.e. time?

infinite - is used here spatially.

a perpetual motion device set in motion now is infinite (theoretically - not accounting for wear of mechanical parts etc), depite not having been in motion yesterday.

This supposes time itself is sempiternal, there is nothing to suggest that this is an inerrant fact.

... in the very very distant future .... we will not only be dead but will have never have existed.

um, no. that isnt actually possible, due to the fact that i am sitting here. and i am actually sitting here. existance isnt merely for the benifit of consciousness. if in basquillions of year creature come to this exact spot that i am sitting and find no remains of me or my building site house, it doesnt mean i was never here.

I didn't make my point very clear - the drink, it was the drink.

What I meant to say was that in one model of our universe (of the three possible models) - we see gravity eventually overwhelm matter and bring everything together into a singularity (what scientists might call the 'big crunch') - at this point time itself is brought to a halt, at this point you will not only be long dead (I will make sure of that) but there is no time from which to 'project' a past.

yes trees falling make what we call a sound (the waves outside of our bodies) even if there are no ears and brains to figure it out.

If your definition of sound is a definition of the sound waves that dissipate through the air - then I agree.

i think that (i have never cared to consider this before so i have only just decided) that time is infinite. the universe, our universe is finite. but, the space that the universe exists in, is infinite.

Like I said above, I can see no good reason to believe that time is infinite, time is simply a measure of change, unless we are lucky enough to be living in a steady state universe it will eventually grind to a halt (no change).

I agree that our universe is finite - but your idea that the universe exists in something else (!!) that you call 'space' is a strange hypothesis.

The universe means everything - there are not things outside the universe, there is not another 'stage' called 'space' on which the universe plays out !

[Edit] . . . . . . .

Just reading once more what you wrote, you seem to be employing a kind of substrate for everything, (if I understand you correctly) a kind of unspoken/unnamed scaffold to hold everything up, as in:

*Time: Time exists regardless of matter, even if everything is gone, if no matter existed - time would still exist.
The Universe: The universe sits within a substrate called 'space'.
*

I can't really agree with either of these ideas, my own view is that the universe is all there is (it is everything) - and time is simply a measurement of change, it does not exist without change.