Infinity on High finished the year at number twenty-one on IFPI's list of the "Top 50 Global Best Selling Albums of 2007". "Infinity on High" has shipped over two million copies worldwide. The album also charted inside the top five worldwide, making it the band's most successful and breakthrough album internationally. "Infinity on High" charted all over Europe, debuting at number eight on "Billboard"'s European Albums chart. In Australia, it debuted at its peak of number four on the Australian ARIA Albums Chart. It remained on the Australian chart for a total of fifty weeks, spending its first seven weeks in the top
Infinity (i.e., it counts or measures things: "an infinite number of terms") but it is not the same sort of number as either a natural or a real number. Georg Cantor formalized many ideas related to infinity and infinite sets during the late 19th and early 20th centuries. In the theory he developed, there are infinite sets of different sizes (called cardinalities). For example, the set of integers is countably infinite, while the infinite set of real numbers is uncountable. Ancient cultures had various ideas about the nature of infinity. The ancient Indians and Greeks did not define infinity in precise