TIL that Comet Swift-Tuttle is the largest comet to make repeated close approaches to Earth. A collision would release 27 times the energy of the impact that caused the extinction of dinosaurs. It has been described as "the single most dangerous object known to humanity".

https://en.wikipedia.org/wiki/Comet_Swift%E2%80%93Tuttle
#til #todayilearned
https://www.reddit.com/r/todayilearned/comments/1g0sd70/til_that_comet_swifttuttle_is_the_largest_comet/