# How big is Infinity?

1. Sep 10, 2007

### zeshkani

How big is Infinity ?
like eletron is considered the samllest thing ever, wouldnt that be the lowest value of negative inifinty in teh size of things
but overall how big or small is infinity ?

2. Sep 10, 2007

### bob1182006

as small as can be.

Imagine the smallest number you can think of. -Infinity is smaller.

Mainly it's just a concept since it doesn't really equal a number, it's just reallyy small..

Same with +infinity its super big number.

3. Sep 10, 2007

### Kummer

This should rather be in the Particle Physics forums.

4. Sep 11, 2007

### HallsofIvy

Where did you get the idea that an electron is "the smallest thing ever"?

5. Sep 11, 2007

### arildno

Infinity is NOT a real number.
For your practical purposes, that means infinity isn't a number at all.

6. Sep 11, 2007

### Haelfix

Mathematicians throughout the age have always tried to make sense of infinity. You get different answers depending on the era.

For instance I believe it was Cauchy who believed infinity was some sort of limit where negative real numbers reach positive reals. (He probably had the complex sphere in mind)

Nowdays i'd say people view that sort of explanation as quaint -shrug-

7. Sep 11, 2007

### Howers

As it has already been stated, infinity is not a number... it is merely a concept that tells you something goes on forever. In terms of physics, a plank length is the smallest length that has physical significance. While it may potentially be the smallest unit of how something can be seperated by, it is by no means the smallest number. In math, a number does not have to correspond to nature. The complex numbers are an example of this.

8. Sep 11, 2007

### CRGreathouse

That's the projective line -- hardly quaint, I'd say.

9. Sep 11, 2007

### zeshkani

well if infinity is not a number but a concept how do you explain where numbers dont end

like if you draw a circle and start to draw lines from the center accros, and so on until you cant draw them anymore, but you can take a sharper pencil and draw even more lines, there will always be a small gap in between the lines, and this will go on until infinity, because the gap will always remain, so if inifity is not a number why would we even bother using it in mathematics or physics, (i use infinity in calc 3 sometimes, but not in the form as a number tho, just to take certain integrals)

10. Sep 11, 2007

### Kummer

Can someone tell me why there are so many "infinity" "0/0" "1/0" , .... threads? These threads do not belong in math.

11. Sep 12, 2007

### HallsofIvy

Because there are some people who come here who don't belong in math?