I’m not sure where I pulled the number ‘8’ from, but it may be from pathology class from the second year of med school. 8 minutes is the amount of time you’ve got before the lack of oxygen starts causing permanent damage (such that if you do manage to restart the heart and/or reopen the blocked vessel, you may actually cause even more damage than what has already been done—so-called reperfusion injury.)

Surprisingly, when someone is actively dying, eight minutes can actually feel like a terrible eternity.

But weirdly, this factoid has become enmeshed with another piece of (more accurate) trivia: 8 minutes is about how long it takes for light from the sun to reach the earth. Astrophysicists always like to talk about these hypothetical scenarios where you imagine that somehow the sun was extinguished, or went supernova, and it would take eight minutes before Earth actually went dark, or eight minutes for the blasting radiation to hit us.