Stephen Hawking · every age

What was Stephen Hawking doing at 41?

Given two years to live at 21, he worked for 55 more

1. c. 1983

   The no-boundary model of the universe, with Jim Hartle

   A universe with no beginning edge in time.

   Source: en.wikipedia.org

Portrait: Photo: NASA (StarChild), public domain, via Wikimedia Commons · source