Thunderbolts definitely has (big!) issues: I would say it's a mix of some under-appreciated but real science and a lot of loose theorizing that lacks the mathematical rigor, data analysis, and peer review needed to back it up. However, the idea that petroglyphs are human drawings of planetary-scale plasma glow discharges is actually a sound theory; and it's not Thunderbolts' theory, in any case. See my comment above:

https://news.ycombinator.com/item?id=16015017