Penrose: You all have big biceps in your right arm, because you spend
half your lives scrawling tons of chalk dust across miles of blackboard.
I don't do that! I have something magic and wonderful to tell you
about.  It is fast, it is rigorous, and you don't need big muscles.
It is called TOPOLOGY! And nothing moves faster than light at 186,000
miles per second.  Light is the fastest.  Easily fast enough to
overcome the gravity pull of say the sun, or the earth, and escape.
The speed is high enough to get away from the gravity pulling it back.
What if the sun were more concentrated? What if the sun collapsed? The
density becomes huge, the gravity pull enormous.  Now nothing stops
gravity pulling everything in, even light.  A singularity point.  What
is a singularity? A singularity is a place where matter, light, space ...

Hawking: ... time

Penrose: ... everything fold in on themselves, and disappear.
Profound and total nothingness.

Hawking: Everything and nothing.

Penrose: Up to now, all of you people with your big biceps and big
equations have always said: "Oh, my big equation is ending with a
singularity.  I must be wrong".  This did not frighten Einstein.

Hawking: Singularities can't exist because the laws of science don't
allow it.

Penrose: Wrong. Singularities do exist!

Hawking: For perfect spheres. For idealized stars.

Penrose: No.  For real stars.  Real stars do it too.  There are places
where science and rules break down.  Where there is no matter, no
space, nothing.  Where everything , including time, does not exist.
And when a star collapses a singularity is inevitable.  Topology does
not bother with messy stuff like particles, how they move, how they
connect.

Hawking: Big thinking

Penrose: Big bold thinking.  Takes you to places where the rules say
you can't go.

Hawking: And it's fast. You say that it is fast.