He asked us how long everlasting life was. Asked us to think of the
largest number we could think of; not millions or billions, but big
numbers. He did research and the largest number man knows is called a
googolplex. It’s impossible to even write out a googolplex; Carl Sagan
estimated that writing a googolplex in numbers would be physically
impossible, since it would require more space than the known universe provides.
Since he was talking to people who are told this everlasting life would be on earth - did he mention how long the life of the sun is estimated to be?
As I recall, Carl Sagan had some things to say about that as well - and never suggested that earthly humans would live for a "googolplex" number of days, years, or whatever.
I guess he thought he sounded "scientific" because he said "googolplex" and "Carl Sagan" while spouting scientific absurdity.
Oh, and edit to add - if the largest number man knows is a googolplex, then what is infinity?