The digits in Pi (π) are a non-repeatable infinite sequence & black holes have infinite gravity at the center. See Wikipedia for more - Stuart Miniman

The problem of infinity is a big one, and isn't easily answered. It's broken into two parts: can there be infinitely numerous things, and can something be infinitely divisible? For the former, it's becoming more and more likely that beyond the Universe, there is some form of a multiverse that is infinitely large (and containing infinitely many other Universes). For the latter, it's not clear whether space-time itself is infinitely divisible. A basic thought experiment into this part of the infinity problem is Zeno's Paradox: Let's say you have two points, point A and B. In order to get to point B, you need to somehow go halfway, point C. But in order to get to point C, you need to go halfway between it and point A, or point D. Repeat ad infinitum: it seems like you should never be able to get going. Yet, you can get to point B. - Mark Trapp

Is the universe finite or infinite? - LPH™ and his dog P™

LPH: which aspect of it? - Mark Trapp

Depends on what is meant by "anything". If it can include any continuous variable, then yes there are infinite things. Such as an infinite # of distances between 1 inch and 2 inches, etc. - Mike Reynolds

How about the arguments over which social media site is the best and which sucks - that discussion goes to Infinity and beyond ;) - Stuart Miniman

LPH: Theoretically, the matter which should exist in the universe should be finite, while the boundary is still expanding into infinitude. Thus it is hard to say. - Jimminy

If you mean like physical objects then I don't think so. In math there are even different levels of infinity like "countable" and "uncountable" so no. "The theory of infinite cardinals was developed toward the end of the nineteenth century by Georg Cantor. The smallest infinity was that of the set of integers, also called countable infinity and given the symbol aleph-0. The next infinity he was aware of was that of the real numbers, called the continuum or C. The process he used (using the idea of power set, that is the set of all subsets of a given set) generates a whole string of infinities. The basic problem he posed was - is there any infinity between aleph-0 and C, in other words was c = aleph-1? The hypothesis that they are equal is called the continuum hypothesis. The generalized version of it was the assertion that there are no infinities between that of any infinite set and its power set. During the early part of this century, Goedel and others proved that the continuum hypothesis being true or being false were both consistent with arithmetic as developed from basic axioms." - Todd Hoff

Damn kids with their difficult questions! - joneilortiz

I believe God is infinite? - Nestor

Mark - I've read about multiverses, but not really familiar with them. Related to string theory? Or totally different thing? - Hutch Carpenter

Mike - that infinite points between two lines is a lesson I recall from mathematics. I'll have to relate that to Harrison...maybe...how do explain that to a 5 y.o.? - Hutch Carpenter

Time - Ken Sheppardson

Hmm...this is such a good question. - Alex Scoble

Hutch: string theory and multiverse theory (where universes exist on multidimensional membranes known as p-branes that exist close to each other) are part of a larger framework called M-theory ('m' for membrane). Depending on the specific theory, there's a chance there could be infinitely many p-branes. Strings can exist solely within a p-brane, or, in certain cases, exist between p-branes (so called Supergravity). - Mark Trapp

Great question. Succinct, and I don't think I've seen it asked here. - Micah Wittman

Todd - so physical objects are finite. That's what I was thinking. The rest of your comment is some good math there, I tell ya! - Hutch Carpenter

Hutch: the infinite points argument is pretty easy to demonstrate with someone standing 10 ft from a wall. Have them move halfway, then halfway, then halfway, etc etc etc. I'm pretty sure Aristotle did it the same way (or was the S or P, I can never keep 'em straight). - FFing Enigma (aka Tina)

The one thing that stands out growing up as a Buddhist is impermanence. - Rodfather

What Todd said about there being an infinity of infinities in mathematics. As for the physical universe, while the law of conservation of matter and energy makes me think that matter and energy should be finite, we know that virtual particles can pop out of the vacuum spontaneously all the time. Also, most of the current theories of the nature of the universe assume that the density of matter and energy in space is relative homogenous. So if the universe is in fact infinite, then matter and energy must also be infinite. - Victor Ganata

I would tell him that the only thing that is infinite is my love for you. - CW™

Mark - I've read about those membranes. I do love that theoretical stuff, as long as it's brought down closer to a layperson's level. - Hutch Carpenter

CW™ - there you go. I'm using that tomorrow! - Hutch Carpenter

When my soon-to-be 1-year-old son asks a question like this, I'm going to weep (internally) in joy. Such a clever boy! I'd turn around and ask him, "Well, what do YOU think?" That'll help him explore the ideas. - Hiro Asari

hiro: "what do you think?" could be the best question you ever ask your child in their entire life - Tyler Gillies

Tina - good way to explain the infinite points between two points. The Halfway exercise. - Hutch Carpenter

It has to be finite because, whilst the universe is 'expanding' there has to be only so much it can expand into. - Nicholas James

nicholas: good point. because if the "nothingness" beyond our expanded universe was infinite, our universe would not exist - Tyler Gillies

tyler: thanks for the tip. Halfway point exercises is good…good lead into the Dedekind cut. - Hiro Asari

Hiro - I like that sentiment. My son just got this infinite idea in his head, it's fun to talk to him about it. Lots here in this thread to talk to him about. - Hutch Carpenter

I once said 'I infinity infinity infinity dare you!' - Rodfather

except human stupidity - Parth Awasthi

Rodfather: That just reminded me of Buzz Lightyear out of Toy Story "To infinity and beyond" - Nicholas James

Zeno's paradox for the win! - Victor Ganata

Victor - you made me look up Zeno's paradox: http://en.wikipedia.org/wiki... - Hutch Carpenter

Why can't the universe expand into infinity? Some of the cutting edge theories in cosmology believe this may be so: http://arxiv.org/abs... - Victor Ganata

i think the universe would stop from heat death eventually. [entropy] - Tyler Gillies

When I was TA for an undergrad Calculus class, I gave a passage from Gödel, Escher, Bach on Zeno's Paradox in an exam for extra credit to explain the "paradox". They hated me. - Hiro Asari

Tyler, it's actually not a given that the universe is going to end in heat death. The ekpyrotic universe posits that things may actually be cyclical http://wwwphy.princeton.edu/~steinh... This is related to M-theory and the possible existence of p-branes. - Victor Ganata

I think the most honest answer would be "I don't know". ;-) - Peter Sedik

I firmly believe that the number of Note combinations in music is infinite. - Brent - Long Live Rock

Hutch, the easiest explanation I know works well for high school students and some others, but here goes. Stand perhaps 10' from a wall. Then move so that you're 5' away (about). Then cut in half again to 2.5'. Then keep cutting in half. Eventually you'll be 1" away, then 1/2". Then you'll have to explain that you're still moving half the distance each time and that you can still keep on moving like this forever. - Mike Reynolds

But perhaps easier for a 5 year old is seeing how many "words" they can make from the alphabet. Let them jot some words they know on paper, then encourage them to make up new words, even fake ones. If they run out of ideas, encourage them to add some letters. This is a game that never ends, b/c you can always add letters. Thus, this is a kids experience with no end, thus the Universe does contain some "infinite" things. - Mike Reynolds

The variations on how we answer his question approach infinite... - Thom Kennon

And a third one which works for advanced people is constructing a 2D shape that has infinite surface area, yet finite area. - Mike Reynolds

Thom - that's a good point. I'll show Harrison this thread. - Hutch Carpenter

I still remember trying to figure out what I felt about infinity. I think I finally settled on the concept that there was, in fact a number infinity, but whenever anybody said something like 'yeah, well, I'm better then u times infinity' I decided that they couldn't actually, because it's unreasonable to multiply by infinity. - Will Higgins™

Mike - thanks for the "words" yip. You're right, that goes to infinite. Of course, that includes words with a quadrillion letters and beyond. Making up these words would be fun for him. - Hutch Carpenter

We can never know for sure, so we should assume that both finality and infinity are viable possibilities. So if life is finite, final, and ends forever with death we should make the most of the time we have while we can. If life is infinite and loops back on itself, and death is also birth (http://en.wikipedia.org/wiki...), then we should make the most of our every moment because each of our actions has infinite implications. - Garin Kilpatrick

this makes me miss my dad, who was a mathematician. I remember grilling him on the concept of infinity. The first time he explained it to me and I "got it" I could not sleep all night thinking about it. I"m pretty sure I was older than five, though. At least seven, I think. - Laura Norvig

there are finite and infinite games http://www.amazon.com/Finite-... - Valeria Maltoni

Valeria: I've got a Ballantine 1st Edition paperback of that book from 1987 that I've read probably a dozen or so times since. It still sits on my main bookshelf, and I frequently throw it in a bag when I travel to re-read bits from when I'm not otherwise occupied. Definitely more philosophy than science, and I'm guessing not a great read for most 5-year-olds...but still a great read that continues to keep my interest nearly 22 years later (and more years to come, i'm sure). - abacab