(As a more general point, I think it would be a good idea to add a clearly labelled errata section to the show notes any time an error of fact is found in the show.)

if I remember correctly, you say that in about 500 million years, the sun will grow brighter, boiling the oceans on earth & wiping out most or all of life on earth. The solar models that I've seen show the the luminosity of the Sun increasing by perhaps 5% over the next 500 million years. Now we are quickly learning how non-linear atmospheric processes are, so is it some kind of runaway greenhouse gas effect that takes a 5% increase in insolation & produces something like a 30% increase in surface temperature (100 K/300K).

As a secondary question, could you provide an explanation of why the luminosity. effective surface temperature, & radius of the sun all increase over time, while the sun is still on the Main Sequence. I gather this has something to do with the buildup of "ash' (entirely He or other elements too ??), but the connection between the buildup & the increased luminosity is unclear to me.

But honestly, I think there is some technology we're not likely to ever achieve. I'm going to blog about this over on StarStryder in a few hours if you want to find out why.