All forms of ionizing radiation can be blocked with some form of shielding. Even a man tended observatory must take ionizing radiation into account. You are almost as inconsistant as BD.

Starting sporadic fires hardly qualifies as setting the surface of the Earth on Fire. If the entire surface beneath its path was set on fire it is unlikely any would have survived to tell the tales you claim are actual history. As usual you greatly exagerrate the effects of small scale impactors as well as their frequency.

Let me know when you've finished fudging your dates.

Regards,
Mark

PS What was Dr Impact's last reply? I missed it and Robert still has the post cross-threaded. I think we both have a guess as to who he is. Amazing how much animosity he has towards you.