If all humans died, when would the last light go out?

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?

Henry Reich is the creator of MinutePhysics and executive producer of MinuteEarth and MinuteFood and founder of Neptune Studios (the parent company for all three youtube channels).

Credits
Narrated by and based on "What If?" by Randall Munroe
Written & Directed by Henry Reich
Illustration and Video Editing by Lizah van der Aart
Illustration and Animation by Ever Salazar
Music & Sound Effects by Know Art Studios

What If? The Video Series is the official adaptation of the What If? books by Randall Munroe and is produced by Neptune Studios LLC.

©2024 xkcd, inc.

[hazelhazelton]

There is something immensely sad about the thought of an emergency phone in a remote location still being functional even though the world is now void of human life. So if you were the last human, and you found it, you could make a call, but nobody would be there to answer.

And the last human voice you ever hear is a recording going "The number you are trying to reach has been disconnected."

[loganscottbermejo]

I need a version of this video where he says "If every human somehow simply disappeared from the face of the earth" and then just 5 minutes of silence after the stick figure gets vaporized

[RealSwiggs]

Have you guys ever watched something brand new and it immediately feels old-timey? I cannot explain it but it feels like this is something I would've watched 10 years ago. Very comforting to know people are still making content like this. Shorter videos, straight to the point, informative and NO SPONSORS.

[chrisrojas]

The check engine light in my car will always be shining

[DeusExMcKenna]

If a fire set by mankind counts as an "artificial light source", the Centralia PA mine fire could continue burning for 250+ years by some estimates.

[Protactiniumm]

That solar panels segment seems missing one important note: although, the solar panel might produce electricity well past it's EOL which is about 25-30 years, it's the battery what will fail first after years of everyday charging cycles. Much much sooner than any solar panels lifespan. So after 20-25 years, the solar panel will be basically trying whole day to charge the dead battery, which means no more light during evening.

[ZelphTheWebmancer]

The scarier part isn't that the sign at 3:00 was changed from Everyone to 0, but the question who change it?

[napalmsushi]

"Check out this glowing blue stick I found in that hole past all the spikes!"

"Huh. Must be a place of honour. Highly esteemed deeds must be commemorated there. Stuff that's valued must be there. I bet what is there is cool and awesome to us."

[qriminalized]

The immortal hamster powering the White House:

[sicovulze]

Imagine you are somehow a survivor and make it through another 50 years or so and somewhere in a remote location you see a light powered by a solar panel... Would be an emotional moment

[kalkuttadrop]

For years, scientists debated how to mark nuclear waste sites to protect our descendants.
Apparently recently they've decided the best approach is to just bury it deep enough in a secure enough place that any future civilization advanced enough to get at it will probably know what radiation is and be able to manage it.

[brozbro]

How many years could you go back in time and still have breathable air?

[pancakesareawesome]

3:00 woah woah woah woah. So this hypothetical takes place in the same universe where everyone was teleported to rhode island and forced to jump? This opens up the theory of all videos takes place in the same universe, and in which case, the xkcd universe would be a terrible place to live

[evah]

I love the Tom Scott "cameo" at 1:56 !

[thinking]

"When the last light goes out" is a hell of a title for a post apocalyptic movie/book

[kevin_heslip]

This video is the type of thing that got me into YouTube when it used to be a website

[Mochi-lfrz]

I found a digital clock in our attic that's been running for over 20yrs on AA batteries and it was only 5-6hrs off the actual time. Its still running without a battery change 6+months later I'll keep it around till it dies

[samuraijacksson]

the light she brings to my life could never be extinguished

[silverXnoise]

Today I learned Tom Scott no longer makes YouTube videos because he’s taken a job maintaining all wind turbines. Thank you for service, Tom Scott.

[PiscatorLager]

The last thing remaining of human light technology being garbage is philosophical as fuck