The Most Extreme Explosion in the Universe

A Type II supernova within 26 light-years of Earth is estimated to destroy more than half of the Earth's ozone layer. Some have argued that supernovas within 250-100 light-years can have a significant impact on Earth's environment, increase cancer rates, and kill a lot of plankton. They can potentially cause ice ages and extinctions. Within 25 light-years, we are within a supernova's "kill range." Fortunately, nothing should go supernova close to us for a long time. Wikipedia article: link Kurzgesagt video on the impact on Earth of supernovas at varying distances: ▶ this video

While I like the ambition, supernovae turn out to be one of the least likely extinction scenarios. Their video on this points out why: ▶ this video there aren’t any stars close enough to do damage in that time frame. I used to worry (as one does) in my 20s about quasars, but those are basically sniper rifles being fired in random directions. The probability of one scoring a critical hit is far less than a giant rock hitting us, which is probably the more pressing concern. I’m sadly bearish on us ever getting out of our solar system. I think AIs will be able to, but flesh and blood is ill suited for the journey. And as much as I love our mechanical overlords^Wfriends, they’re ill suited for colonization via reproduction, unless you buy the theory that swarms of nanites could really become viable.

Kurzgesagt just did a vid on black holes and how close they have to be before we're f'd. The Most Extreme Explosion in the Universe ▶ this video