Actual infinites

**Ted Logan** · 10-06-2010, 10:07 PM

Do they exist?

JerryLove · 10-07-2010, 05:13 AM

Don't know, but don't think so.... at least not in regards to the universe and everything in it.

**Rainer.** · 10-07-2010, 11:17 AM

Could the medium in which the universe exists be a physical infinite?

**Ted Logan** · 10-07-2010, 01:20 PM

You mean "extending infinitely in every direction"?

If that's what you mean, I don't think it would make sense - A finite thing (the universe) existing within an infinite space would seem to be problematic. After all, you would then have an infinite amount of space in every direction around the universe. But that would mean that the total size of the medium (infinity) would be equal to the total minus the size of the universe. So infinity minus infinity would equal the size of the universe.

**Skeeter** · 10-07-2010, 03:02 PM

They're necessary in certain branches of mathematics, but in terms of the "real," I would say no. Of course, this all depends on your definition of "actual." Is the thought or idea of infinity an "actual" infinite? Is the theory of infinity an "actual" infinite?

**Ted Logan** · 10-07-2010, 03:10 PM

I think that in mathematics, you have the use of infinites within a self-contained logical system where rules apply to prevent you from doing calculations that lead to absurdities (such as the one I mentioned). But those rules are stipulated to make the "game" work. I tend to think there are no actual infinites unless we want to conceptualize God as such, but maybe I'm missing the point

JerryLove · 10-08-2010, 06:07 PM

Quote:

Originally Posted by Rainer.

Could the medium in which the universe exists be a physical infinite?

Does the universe exist in a medium.

Certainly it is posible that it does, and possible that the medium in infinite. There's just no data.

On something a little closer to home: a black hole *may* have an infinite radius: that's why they are measured by circumference, because the radius cannot be calculated.

athanatos · 10-10-2010, 08:24 PM

Quote:

Originally Posted by JerryLove

Does the universe exist in a medium.

Certainly it is posible that it does, and possible that the medium in infinite. There's just no data.

And no way for us to know. Or maybe there is, but I am just thinking there is no way we could ever prove it or have a definite criterion. Or, well... if the universe is shrinking or expanding, it seems like it would imply something like that, if we could know that the whole universe is doing so...

Quote:

On something a little closer to home: a black hole *may* have an infinite radius: that's why they are measured by circumference, because the radius cannot be calculated.

You have thoroughly confused me. How do you arrive at the circumference without a radius? Or is it just event horizon measured, and assuming an infinite influence-radius?

JerryLove · 10-10-2010, 08:47 PM

Quote:

Originally Posted by athanatos

You have thoroughly confused me. How do you arrive at the circumference without a radius? Or is it just event horizon measured, and assuming an infinite influence-radius?

Take a piece of paper, laid flat, with a circle with a circumference of a given value. That circle will have a radiuse of c / 2pi.

Now imagine an inverted traffic cone (so the big end of the funnel is at the top) with a circumference of the same value. Put a tape measure on point and measure to another, in a straight line, passing through the center (point) of the cone, making sure to always keep the tape measure in contact with the cone.

That value will be much higher than c / 2pi,

Spacetime, particularly in the vicinity of a huge mass, is more like the cone than the piece of paper.

If we could take a ruler in a straight line from one edge of an event horizon to an opposing edge (though the center), it would be far more than it would in "flat space"... possibly infinite.

RadioHead67 · 10-11-2010, 01:00 AM

The only infinites i can think of are that with life will definately come death. Also that 1+1=2 but im sure ppl can argue against that

**Skeeter** · 10-12-2010, 10:46 AM

Those are not infinites; those are certainties. Very different things.

RadioHead67 · 10-12-2010, 12:08 PM

Quote:

Originally Posted by Skeeter

Those are not infinites; those are certainties. Very different things.

What is your definition of a infinite? Something that does not have end?

**Ted Logan** · 10-12-2010, 12:33 PM

An infinite in this case is a set or series that extends without limit. So for example, the set of all real numbers is infinite - it goes on forever. The set of all integers is also infinite. If God is eternal, then His existence is infinite in duration.

athanatos · 10-12-2010, 09:12 PM

Quote:

Originally Posted by JerryLove

Take a piece of paper, laid flat, with a circle with a circumference of a given value. That circle will have a radiuse of c / 2pi.

Now imagine an inverted traffic cone (so the big end of the funnel is at the top) with a circumference of the same value. Put a tape measure on point and measure to another, in a straight line, passing through the center (point) of the cone, making sure to always keep the tape measure in contact with the cone.

That value will be much higher than c / 2pi,

Spacetime, particularly in the vicinity of a huge mass, is more like the cone than the piece of paper.

If we could take a ruler in a straight line from one edge of an event horizon to an opposing edge (though the center), it would be far more than it would in "flat space"... possibly infinite.

I think I know exactly what you mean now. Given your explanation, I think I would've explained it differently, but essentially mean the same thing. Thanks.