Isaac Newton · every age

What was Isaac Newton doing at 42?

Invented calculus and gravity theory in a plague year at 23

1. c. 1685

   Posed and solved the minimal resistance problem

   The first problem in the calculus of variations, published later in the Principia.

   Source: en.wikipedia.org

Portrait: Portrait: Godfrey Kneller (1689), public domain, via Wikimedia Commons · source