Comet 67P...

Comet 67P...  Every time I look at one of these images, I marvel that I live in an age where I can sit in my living room and look at photos taken just hours ago by a camera located very nearby a comet! 

When I was a boy on our farm in New Jersey, comets were largely mysterious objects about which there was far more speculation than actual knowledge.  Not so many years later, we have sent robotic explorers to two comets, we have several more such explorers that will be visiting, and we've gained an enormous amount of concrete knowledge about comets – including magnificent photos like these, streaming back from the Rosetta spacecraft.  While there are still many mysteries about comets (especially about their origins), there's a solid base of knowledge and understanding now – there's more knowledge than speculation...