You know what blows my mind? When humans spend exorbitant amounts of time and energy perusing terrible ideas. Case in point: hydrogen filled airships. Everybody knows about the Hindenburg disaster, where one of the largest rigid-framed zeppelins ever built blew up in spectacular fashion in 1937.
It was this gargantuan disaster that finally tipped the scale of public perception towards believing hydrogen filled airships were a bad idea. That I understand. What blows my mind is that despite countless prior examples of why the idea is flawed, there were thirty years of steady progress towards building bigger and better flying bags of hydrogen gas! Good lord people! Common sense! I've got an experiment for you: start with a child, one just barely old enough to recognize that some ideas are inherently dangerous (let's say a six year old). Then fill a party balloon with hydrogen gas, attach it to a string and hand it to the child. Finally, hold a lighter to the balloon until the gas ignites. Now ask this slightly scorched, terrified six year old if he or she thinks it's a good idea to build REALLY REALLY BIG balloons filled with the same gas and fly around in them. The kid would say no. I was reading about the history of airships today, and while there were some marvelous triumphs -- crossing oceans in a third the time of an ocean liner in superb luxury, hauling tons upon tons of cargo into the air, circumnavigating the globe -- the history of airships is absolutely littered with horrible accidents. Most of the big airships that saw real use met a fiery, high-impact end. And yet the idea persisted. "We can get around the safety issues," they said, "airships are the future!"
Airships might be the future, but not hydrogen ones.