“You have to find out what you can’t know before you know you can’t, don’t you? (…) The point is people must think, people must go on thinking, they must try to extend the boundaries of knowledge and they don’t sometimes even know where to start. You don’t know where the boundaries are, do you?” Stephen Hawking’s mother, Isobel Hawking Walker, in A brief history of time – Errol Morris (documentary film 1991).
Stephen Hawking’s big ideas … made simple – video animation-The Guardian: https://www.theguardian.com/news/video/2013/sep/19/stephen-hawking-history-time-simple-video
A brief history of time – Errol Morris (documentary film 1991): https://youtu.be/GiIIx6oh0pk
A Brief History of Time – Wikipedia: https://en.wikipedia.org/wiki/A_Brief_History_of_Time
Into a Black Hole – Stephen Hawking: http://www.hawking.org.uk/into-a-black-hole.html
Travelling to Infinity: My Life with Stephen – Wikipedia on JaneHawking: https://en.wikipedia.org/wiki/Jane_Hawking …
The Theory of Everything (2014 film)- Wikipedia: https://en.wikipedia.org/wiki/The_Theory_of_Everything_(2014_film)