Johnny Carson was the undisputed king of late-night TV, and “The Tonight Show” was one of my all-time favorites. I seldom missed his monologue, punctuated by Ed McMahon’s belly laughs. But I also loved the electric lineup of guests, such as The Great Kreskin, Marlin Perkins, George Burns and astrophysicist Carl Sagan. Carson infamously said “billions and billions,” parodying Sagan’s emphasis on billions, not millions, in an interview. Sagan has since received credit for that line. But either way, even today I have a hard time getting my head around the concept of a billion. A billion is 1,000 million. If you stacked ... (full story)