When we get all caught up thinking about the zombie apocalypse, the robot revolution, or something a little more realistic, like say, an antibiotic-resistant superbug that could seriously wipe millions of us out, we're talking small-time 'end of the world' stuff. Robots might rise up against us and destroy humanity forever, but the world will keep on spinning, and the Solar System will still have eight planets (sorry Pluto).
But nothing is forever, no matter how many billions of years you've existed, and theoretical physicist Brian Greene just demonstrated to Colbert how a star like our Sun will end.
Now, we don't want to alarm you or anything, but at some point, our Sun is going to run out of fuel, collapse in on itself, and everything we know and love will die.
If you have kids, that's something you maybe want to give the delicate 'birds and the bees' treatment to when it comes time to explain that little nugget of truth to them, lest they end up like one of Louis CK's daughters, when he decided to marvel at the incredible, flaming violence of it all:
"She started crying immediately, crying bitter tears for the death of all humanity… and now she knows all of those things: she's gonna die, everybody she knows is gonna die, they're gonna be dead for a very long time, and then the Sun's gonna explode. She learned that all in 12 seconds, at the age of seven."
The sad futility of existence aside, the science behind how and why a star millions of times more massive than our Sun implodes in on itself is fascinating, and nobody explains it as clearly as Greene in the video above.
And he takes things one step further, by bringing a record-breaking Galilean canon into the studio to demonstrate just how far the shockwaves of destruction will emanate from a dying sun. Dude makes breaking a world record look suspiciously easy.
Correction: The story has been corrected to make clear that the star Greene talks about in the video is much more massive than our own Sun.