is space infinate?

[Maze1125]

True, but this logic only applies to mathematics. The universe did not go from zero to infinite in a flash, as is the case with the natural number line, but from quantum-scale to non-quantum-scale-but-still-finite (no one can say with any certainty if it actually had zero size, because we currently don't have a working theory for how gravity behaves at the quantum-scale), and then kept growing.

Actually, the key point is that in the early universe, from any given point in the universe, the observable universe was below the quantum scale. That says nothing about the total size of the universe at that time.

The problem is the mathematical concept of infinity. It's not a number (so yeah, you did butcher his statement ;-) ), but rather the idea that "whatever number I'm thinking of is greater than whatever number you're thinking of".

Actually, there are many number systems where infinity is consider to be a number.

The number line refers to the Real set, it is infinite by definition, it is not expanding.

You're constraining yourself pointlessly.
Yes, the standard view real number line is considered to be infinite and stationary, but that doesn't mean you can't talk about it expanding or contracting and consider the consequences.

If you were to place the natural numbers on the real line there would be a distance of exactly one between each number else they would all be at the same point.

Not necessarily, they are many measurement metrics that can be placed on the real numbers. Saying the distance between 0 and 1 is 1 is just a standard, not a necessity.

However, it's simpler to think that there are an infinite number of natural numbers

They are an infinite number of natural numbers, I've never said otherwise. My point is talking about what happens when those infinite number of numbers are shrunk down until they are all in the same place.

 

[beddo]

Current scientific theory is the space is infinite and expanding.
This is not a contradiction.

Take the number-line. That is infinite in every direction.
Now stretch the distance between each number to twice it's current length.
You have now expanded that number line despite the fact it is infinite.
The universe is expanding in exactly the same way.

The universe started out at a single point. In order for it to be infinitely big then it has had to be expanding for an infinite amount of time

That's not true.

If you took the natural number line and compressed every distance between each number to zero, then the number line would be a single point, but if the distance between each number was even slightly greater than zero, then the number line would be infinite again.

The number line has no direction, it is an arbitrary line.

We do not think the universe is definitely infinite, it has no boundaries but is not infinite. By definition infinity cannot expand, it simply is infinite.

We believe it started at a single point and caz105 is correct, as the universe is expanding at the speed of light, more or less, then it would need to go on forever to actually become infinite.

There is no Natural Number line, the natural numbers are just positive integers, whether it includes 0 depends on what definition you choose. Your 'compression' technique is irrelevant, you're basically just saying if you make all numbers zero they will be zero. What argument is there to be had from this?

 

[TheMadTypist]

My sister is big into this stuff, she's even majoring in Astronomy because of how much she likes it.

Apparently they did an experiment recently, and she was very exited about this, that proved the universe was flat, not curved. Something to do with radiation at the south pole, I think.

So, infinite in the sense you can pick a direction and just keep going, probably. not in terms of the stuff like galaxies and stars, that's only within a radius of where the universe started from.

 

[Nullphantom]

Does it really matter? It's not like we're going to get far enough into space to find out.
OT: Since the universe is expanding, I'll go with yes

 

[Valkyira]

Of course its infinite. Remember children, only games have invisible walls.

 

[shifty89]

its crazy to think about the scale but unfortunately until we learn to use some more of that lovely untapped brain potential, its something thats going to stay uncomprehendable to our minds. I do like the theorys of how the universe will end though. Im a fan of the Big crunch senario personally as it seems to make the most scense though there are countless others.

 

[Malkavian]

The universe is not infinite, as we understand the word. Neither is it finite.
The universe, and indeed existence in itself, is something that lies outside the scope of human understanding. we can try to understand certain aspects of reality, but we will never know the truly concrete whys and hows.

 

[GrinningManiac]

I'm a big fan of the Oscillating Universe theory (Sp?)

I remember in class when we were talking about various theories, I came up with one about how the universe will forever push in and out in the way the theory descibes (this being before I knew of the theory) The next thing my teacher said was the Oscillating theory. I was well chuffed

 

[Woodsey]

Oh yeah, take a look at this: http://buytaert.net/we-are-small-and-insignificant

Be warned, your mind will probably implode. It's quite astonishing.

If the picture is over 16 billion light years away (or 800 million as it says in the end), then how were we able to get the picture in four months?

Oh yes, I forgot I was the first ever 15 year old with a degree in a lot physics and shit...

Oh actually I know the answer. I think you've misread. The light we get from the Sun is 8 minutes old, so when you look at the Sun (it's my understanding that) you're looking at what it looked like 8 minutes ago.

They're saying in the picture, that the image you see (which you see from the reflection of the light) is 13 million years old. So you're sort of seeing those galaxies as they were in the past, because that's how long it takes the 'image' as it were to travel.

So the images in that photograph show us what it looked like 13 billion years before (when the Universe was relatively quite young). Basically it's a picture of the past.

Now there's a mind-fuck.

 

[Ph33nix]

no its curved, go physics

 

[Ironic]

It doesn't blow my mind. I just never think of what could be beyond....

Once you do you get into trouble

Once again, Futurama has solved this question already.

We are outside the box, but also in it.

D:

 

[beddo]

The number line refers to the Real set, it is infinite by definition, it is not expanding.

You're constraining yourself pointlessly.
Yes, the standard view real number line is considered to be infinite and stationary, but that doesn't mean you can't talk about it expanding or contracting and consider the consequences.[/quoe]

I know you can factor and do whatever you wish to the number line, I fail to see the relevance of that.

If you were to place the natural numbers on the real line there would be a distance of exactly one between each number else they would all be at the same point.

Not necessarily, they are many measurement metrics that can be placed on the real numbers. Saying the distance between 0 and 1 is 1 is just a standard, not a necessity.[/quote]

If you attach the natural numbers to the Real number line they will each be a distance of exactly one from the next number, that's just fact.

It doesn't really matter though because there is no Natural Number line.

However, it's simpler to think that there are an infinite number of natural numbers

They are an infinite number of natural numbers, I've never said otherwise. My point is talking about what happens when those infinite number of numbers are shrunk down until they are all in the same place.[/quote]

well you're effectively just factoring the natual numbers, you can only do this with integers because otherwise they would cease being natural numbers. If and only if you multiply them by 0 will they all be at the same point.

 

[Maze1125]

By definition infinity cannot expand, it simply is infinite.

You're wrong on multiple counts.
There is nowhere in the definition of infinity that states it cannot expand.
Infinity is not simply infinite, they are many different infinities, all of different sizes.
Infinity may not be able to expand in the standard way, but they in no way prohibits something that is infinite from expanding.

There is no Natural Number line,

Why not? I can write down the natural numbers in order on a line with even spacing and voila.

the natural numbers are just positive integers, whether it includes 0 depends on what definition you choose.

Yes, you're right. I did actually mean the integers, but it doesn't make much difference.

Your 'compression' technique is irrelevant, you're basically just saying if you make all numbers zero they will be zero.

No, I'm not.
I'm saying that if you take something that has an infinite number of points with even spacing, then compress that spacing until it is zero, then the line of points that was infinite is now simply a point, but any arbitrarily small time before it was compressed to a single point, it was still infinite.

The number line was simply an example of such a spacing of points.

 

[dnnydllr]

If the universe is ever expanding, which science says it is, then no, it isn't. Infinity can't be expanded because you could reach the point of expanse, therefore making it finite.

 

[beddo]

Yes. Of course it is. It's infinite and expanding.

If it's infinite then how is it getting bigger?

Infinite doesn't mean it's restricted to a certain figure.

What's infinity + 1?

You can't have infinity + 1. Infinity is not a number in that sense, it has its own set of rules that are different to the regular numbers we deal with.

There are different sizes of infinity but you cannot manipulate any of them using normal mathematical operations.

It's quite possible to manipulate infinity using normal operations, it's just that most of the answers are just infinity again.

infinity + 1 = infinity
infinity + infinity = infinity
infinity * 2 = infinity
infinity * infinity = infinity
infinity / 2 = infinity
infinity / 0 = infinity (zomg division my zero!!!)
infinity^2 = infinity

A few give different answers.

infinity * 0 is undefined, as it could be any number.

And for any given infinity, which we will call x for now, 2^x > x

It is pointless using normal operations on infinity because they have no effect. The only exception is multiplying or dividing by zero which just gives you a result of undefined.

 

[Rooster893]

No. Nothing in this universe is infinite or perfect.

That's not depressing, right?

It is to me. The fact that we're not going anywhere makes me feel very comfortable.

 

[Maze1125]

If you attach the natural numbers to the Real number line they will each be a distance of exactly one from the next number, that's just fact.

No it isn't. It's a choice, a sensible one, but nevertheless, just a choice.

Most of the rest of your points were addressed in my post directly after yours.

 

[Maze1125]

Yes. Of course it is. It's infinite and expanding.

If it's infinite then how is it getting bigger?

Infinite doesn't mean it's restricted to a certain figure.

What's infinity + 1?

You can't have infinity + 1. Infinity is not a number in that sense, it has its own set of rules that are different to the regular numbers we deal with.

There are different sizes of infinity but you cannot manipulate any of them using normal mathematical operations.

It's quite possible to manipulate infinity using normal operations, it's just that most of the answers are just infinity again.

infinity + 1 = infinity
infinity + infinity = infinity
infinity * 2 = infinity
infinity * infinity = infinity
infinity / 2 = infinity
infinity / 0 = infinity (zomg division my zero!!!)
infinity^2 = infinity

A few give different answers.

infinity * 0 is undefined, as it could be any number.

And for any given infinity, which we will call x for now, 2^x > x

It is pointless using normal operations on infinity because they have no effect. The only exception is multiplying or dividing by zero which just gives you a result of undefined.

infinity / 0 is perfectly well defined in number systems where infinity exists as a number.
And, as I said, 2^infinity gives a greater infinity than you had before.

And yes, many operations with infinity are essentially pointless to do for their own sake, but that doesn't mean you can't do them, as you claimed before.