Discovery If All Humans Died, When Would the Last Light Go Out? Scott Admin posted on 2 years ago — updated on 1 second ago 209 views If every human somehow simply disappeared from the face of the earth, how long would it be before the last artificial light source would go out? earth humans light Scott Follow Author, educator, musician, dancer and all around creative type. Founder of "The Happy Now" website and the online jewelry store "Silver and Sage".