I concur that Chuck McPartlin was or still is an outstanding speaker for the Santa Barbara Astronomical Unit (SBAU).
One day, I was looking at the relativistic time dilation formula: t = t0((1-(v/c)2))1/2 where t = space traveler time, t0 = Earth person’s time, and v is the spacecraft speed.
That evening I went to an SBAU meeting. I went up to Chuck excitedly and said, “Look what I discovered! If a person is traveling at 0.9 the speed of light, he or she can arrive at Alpha Centauri in 1.097 years.” Chuck looked at me and said, “Oh no, no, you got it wrong! You would still have to travel 4.367 ly [light-year] distance to get there. The people on Earth you left behind would age 4.367 years and you would age only 1.097 years.” I then started walking to my seat puzzled, and Chuck shouted, “Besides that, if you found a way to travel at the speed of light, you could live for eternity.”
The very next day, I began purchasing season tickets for the UCSB Women’s Basketball games.