Imagine a balloon that is infinitely wide. Someone blows on the balloon so it's twice as wide. You can't measure how big it is (it's infinite!) but you **can** measure how the surface of the balloon changed -- everything on the balloon is now twice as far apart.

No you can't measure how the surface changed, the surface is also infinitely large, the surface NEVER ends, You cannot see the start of that surface nor can you see the end. It is impossible to judge how the shape of an infinite object changes.

And yes, infinity can mean a number that never ends.

Consider a number divded by infinity, we figure this out by taking the limit of ,say 10/x, as x tends to infinity. We keep making x bigger, and bigger, and bigger.

That answer never reaches 0! We have to keep making x bigger, and bigger, and bigger, as 10/x then gets closer, and closer and closer to 0.

This process never ends, infinity goes on forever and CANNOT be measured in any way (unless we're dealing with some expression that we can simplify). This has nothing to do with physics (which i only studied up to "phys 101") but has to do with mathematics that i work with every day.

The difference is that we KNOW that infinity never ends, it is completly unquantifiable, therefore 10 divided by infinity must equal 0.

The reason is to take this paradox (something which Newton addressed when he originally published differential calculus). Imagine you are walking towards your friend, you keep cutting the distance between you in half.

First you are 10 metres apart, then 5, then 2.5, etc... How can you ever touch your friend if the distances keep getting infinetly smaller? Because infinity goes on forever, thats why. At infinity, the distance equals 0.