125x

Part of Science · All guides

The Black Hole Bomb and Black Hole Civilizations: summary

The Black Hole Bomb and Black Hole Civilizations

Kurzgesagt · Apr 22, 2018 · about 8 min

Uploaded Apr 22, 2018 · 29.5M views (as of Oct 30, 2026)

Good value given

Collapsing stars keep their spin, so black holes can rotate millions of times a second.
A spinning black hole's singularity is a ring, which Kurzgesagt calls a 'ringularity'.
Inside the ergosphere you'd have to move faster than light just to stand still.
Dropping mass into the ergosphere the right way can give you back more energy than you put in, called the Penrose process.
Bouncing waves between a mirror and the black hole amplifies them, which is called superradiant scattering.

How could you build a bomb out of a black hole?

Spinning black holes drag space around them in a region called the ergosphere, and you can steal some of that spin energy. Wrap a spinning black hole in a giant mirror and shine waves at it, and the waves bounce back and forth getting stronger each time. Let the energy out slowly and you have a power source for trillions of years. Keep it trapped and the mirror eventually shatters in an explosion as big as a supernova.

Worth watching?Good value given. Eight minutes, beautiful animation, and a genuinely mind bending idea explained simply. Easy to watch in full.

ActionableLessons

Actionable

Look up the Penrose process if you want the physics behind the video.
Watch Kurzgesagt's other videos on the end of the universe for the bigger picture.
Use the swimming pool versus wave pool comparison to explain the idea to someone else.

Lessons

Things that spin don't want to stop spinning, and that rule scales up to black holes.
Ideas that sound like science fiction can still be grounded in real physics.
Even the most destructive things in the universe can be a source of energy.

Quick answer

Kurzgesagt posted this video on Apr 22, 2018. Here's our summary in our own words: the answer to the title, a verdict, 5 takeaways, and Actionable and Lessons tabs.

What 125x is: 125x is a web app at 125x.app. You connect your YouTube subscriptions, and it gives you a feed of the latest videos from the channels you follow, each with a summary: a verdict, the 5 key takeaways, and the spoiler, plus Actionable and Lessons tabs with more tips. You read that and decide what's actually worth opening.

Open 125x

Watch the video

Watch on YouTube: The Black Hole Bomb and Black Hole Civilizations

Channel: Kurzgesagt. Published Apr 22, 2018. About 8 minutes.

The video isn't a how-to. Its takeaway is that rotating black holes may be the last energy source life could use once the stars burn out.

Quotes from the video

“Black holes are the largest collections of pure violent energy in the universe.”
“A ringularity is a ring with a thickness of zero and no surface, spinning extremely fast, containing all the mass of the black hole.”
“It turns out that even without any light, there are places we can go.”

A note on this summary

This page reports what the video says, in our own words. Quotes are copied word for word from the video's transcript. Views are as of Oct 30, 2026.

How 125x does this for your feed

This page is one sample of what 125x does for every video in your feed. 125x pulls in your YouTube subscriptions automatically, so there's nothing to set up. Each new video gets a watch, skim or skip verdict, 5 takeaways, the answer to the clickbait title, and Actionable and Lessons tabs.

View your YouTube feed at 125x speed. YouTube summaries of every video in your feed.

FAQ: questions people ask

What is a black hole bomb?

A spinning black hole surrounded by a mirror. Waves bounce between them getting stronger until, if they aren't released, the mirror shatters in a huge explosion.

Can you get energy out of a black hole?

Yes, in theory. Spinning black holes can give up some of their rotational energy to things passing through the ergosphere.

Is the video worth watching?

Good value given. It's short and very well explained.