Sophus Lie - how a professor from Leipzig inspired "a calculation the size of Manhattan"

The Norwegian mathematician Sophus Lie (1842-1899) was founder of a whole new branch of mathematics („Lie theory“) by creating the groups and algebras which carry his name. Indeed, Lie groups are the main tool for describing continuous symmetries! From 1886 to 1898, Sophus Lie was a professor of mathematics in Leipzig as the successor of Felix Klein. Wilhelm Killing's first paper on the classification of simple Lie algebras from 1888 was the first hint that the new area would produce wast amounts of research data - which it does up to this day. We will retrace the role and different stages as well as formats of research data in Lie theory, and we will explain what the NY Times meant in 2007 by "A Calculation The Size Of Manhattan“ (spoiler alert: it has to do with the exceptional Lie group E_8).