# What is Infinity?

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Myself and a few friends have been wondering what exactly infinity is, and does it really exist? i, personally, do not believe in infinity. what are your views?

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What about the infinite amount of numbers? Do they also not exist? I can't imagine there being a limit .

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If you don't know what it is, how do you know you don't believe in it?

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Mathematically, infinity is a representation of a concept. It is not a real number.

Temporally, it is time without end (eternity).

Popularly, it is the point which must be reached and then transcended by Buzz Lightyear.

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Mathematically' date=' infinity is a representation of a concept. It is not a real number.

Temporally, it is time without end (eternity).

Popularly, it is the point which must be reached and then transcended by Buzz Lightyear.[/quote']

I never thought of it as technically time. Anything that can go on and on and never stop is infinite. Th amount of numbers, maybe time, etc...

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Temporally' date=' it is time without end (eternity)[/quote']

Would time be infinite if an apocalypse took place?

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The Apocalypse does _not_ stop time. Time cannot stop.

EDIT: Time isn't just something we have on Earth. Time is everywhere. Just because we are not here to experience it doesn't mean it isn't there. The rest of the universe will continue to grow as time progresses.

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Would time be infinite if an apocalypse took place?
If said apocalypse caused the universe to cease being (would have something to do with singularities, clothed or otherwise) then no, time would not be infinite.

If, which is more likely, said apocalypse destroyed every living thing in the galaxy and reduced the whole thing to rubble (collision with another galaxy ought to do it) then yes, time would still be infinite.

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Would time be infinite if an apocalypse took place?
As long as matter exists in motion, yes, but I don't want to derail this thread into cosmology or physics. Since the OP placed this thread in General Mathematics, let's go with infinity as a mathematical representation.
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the point at infinity of C is the point added in the one point compactification, there are one or two points added to the real line in their compactifications coomonly called (plus and minus) infinity, and these extedned systems have soem *limited* arithmetic before anyone starts asking what infinity over infinity is. it is useful to say thigns in mathematics tend to infinity if they grow without bound (ie converge to the point at infinity in the one point compactification)

infinity is thus, if you must, just as "real" as anything else in mathematics and can be said to exist in what ever sense you take anything in mathematics to exist.

i suspect though you may not wish to post this in the mathematics section since you are talking, probably, in a non-mathematical sense, though i doubt you know this.

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It was probably intended to be mathematical but I introduced the concept of physics, afterall maths isn't totally independent of physics.

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I think it would depend on the angle you are veiwing the concept of infinity.

I could analyze this until Darwin came into play.

hmm...my wandering thought that sparks your wandering thought and so on...heehee.

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independent or otherwise is moot and would depend on your opinion. my comments were aimed at the OP and have nothing to do with physics. why single out "infinty" in soem undefined sense for sepcial consideration of platonism in mathematics? as soon as they care to define what they think "infinity" might be the easier any conversation would be.

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what i dont like about infinity is that infinity plus one is still infinity. so how can the new infinity be equal to the old infinity if one has been added?

(sorry if these seems pathetic and childish to some other more experience mathematian, im 17, and my mind is just curious)

moreover, i do think that this thread deals with physics too because i thought about it in a physics state of mind also. is the universe infinate? from basic GCSe knowledge (I nolonger study at A Level Physics) i rememebr that the universe is infinate and is always expanding. i therefore ask that how can something which have no end increase in size. for it is the largest possible value. please excuse me if all this nonsense is due to lack of knowledge.

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but what are you defining to be infintiy! mathematically to make sense of that statement you are implicitly working in the extended eral numbers, that is the real numbers and one or two more elements infinity or plus/minus infinity. in that area the arithmetic is defined in such a way that infinity +k=infinity for any other real number k. (infinity minus infinity still doesn't make sense here). there are other systems which have all the usual real numbers and lots more besides in which "infinity+1" is nto the same as infintiy. you see, there are lots of things in maths with infinite labels. the problem is you haven't fixed what you mean to talk about.

do you mean the extended reals, the hyperreals, the ordinals or cardinals? in maths there isn't some handy little object which is "infinity", ideally maths would never use the word for exactly the reasons that your thinkng about. remember (and this may come as a surprise) there are no absolute truths in maths, it is all relative.

so, what makes you think infinity is an object which it even makes sense to add anythig to? what number system are you assuming that you're talking about?

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Infinity + 1 is like saying forever and a day. It's just a saying. Just like infinity + infinity= infinity.

Basically, infinity is just a symbol to represent and unlimited amount of something. Like 0 is a symbol to represent nothing.

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Infinity is not a number. It is a concept.

The universe is not infinite. Only the future is!

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I never said it was a number. I said it was a symbol to represent no limitation.

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The Apocalypse does _not_ stop time. Time cannot stop.

EDIT: Time isn't just something we have on Earth. Time is everywhere. Just because we are not here to experience it doesn't mean it isn't there. The rest of the universe will continue to grow as time progresses.

Time doesn't really exist. It isn't built into the basic physical laws of the universe. Whether time can end or not is irrelevant, because it does not exist in the first place.

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Time doesn't really exist. It isn't built into the basic physical laws of the universe. Whether time can end or not is irrelevant, because it does not exist in the first place.

That's true. But in our sense, in the way we are talking about it, as long as matter exists and grows and shrinks, our basis of time will continue to go on.

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What about the infinite amount of numbers? Do they also not exist? I can't imagine there being a limit .

Infinty!=Infinity

Oh so yeh.

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I can see this going Philosophical quite quickly

Will move it if necessary (edit: not meant as a threat, just as a warning so you know where the thread is)

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Time doesn't really exist. It isn't built into the basic physical laws of the universe. Whether time can end or not is irrelevant, because it does not exist in the first place.

Right time cannot stop. That is what a singularity would be.

Wrong that time does not exist. All of physics is geared

to timerate. It is a measurable physical quantity.

It can slow down.

How does something that doesn't exist change?

You don't have an answer to that!!!

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There are different sized infinities. For example infinity divided by infinity is not 1; it is undefined.

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I can see this going Philosophical quite quickly
Philosophical ? I would have used another word !

It looks like most posters here don't read previous posts carefully; else there would not be statements like "infinity is not a number; it is a concept".

To repeat what matt said (only in slightly different words, and far too loosely, I imagine) : "Infinity" is a number; only it is not defined in the Reals (the set of real numbers), just as 0.75 is a number that is not in [imath] \mathbb{Z} [/imath] (the integers). One way to define it (I think) is simply as the OP put it - it is a number [imath]\aleph [/imath], that satisfies [imath]\aleph + k = \aleph [/imath] for any real k.

The mathematical definition of "infinity" has absolutely no basis in time, space, or Buzz Lightyear

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