Maybe your first taste of infinity was standing between two mirrors, or gazing into the night sky, or simply trying to count as high as you could. Mathematician Dr. David Eisenbud talks about infinity. If you've ever gazed out into the night sky, you know that thoughts of infinity can make your head spin.
Infinity has a precise mathematical definition.
You can tell a set is infinite if you can throw away one element and still have a set of the same size. Say you have the set of all numbers. Now throw away the number one. You still have an infinite set. In fact, it's still the same size infinity.