This week will feature a lot more science, with a nostalgic entry tomorrow, but focusing on the latest issue of  Scientific American  from Wednesday: What was the worst day ever for Planet Earth?  Which could well have been the best for us, as mammals began to develop. What was the worst event for Humanity? World War II? 70,000 years ago when  Homo sapiens  almost became extinct . Our biggest killer, heart disease, explained. First contact with extraterrestrial intelligence. A cosmic mystery is a fast radio burst.  The brand new Chinese 500-meter Tianyan "Eye of Heaven" detected 1,652 independent bursts from just one source over a period of 47 days.  So what?  Well, in a few thousandths of a second ( this is a tiny period of time much shorter than one second ), one burst produces as much energy as our Sun does in a whole month. The Ukraine War, if we survive, will spur more serious talks about total nuclear disarmament. On to the stories of the day: This weekend 13 mass shoot