Earth Built A Nuclear Reactor Before Us

Added: 2026-06-03

[00:00:00]2 billion years ago, deep [music] beneath West Africa, Earth built a nuclear reactor.

[00:00:05]No engineers.

[00:00:07]>> [music] >> No blueprints.

[00:00:09]Just rock.

[00:00:11]Oklo, Gabon.

[00:00:13]1.7 billion years before [music] the first human walked the Earth.

[00:00:18]A billion years before the first dinosaur. [music] In 1972, a French physicist stared at uranium ore from an African mine and knew something was deeply, impossibly wrong.

[00:00:30]The uranium had less U-235 [music] than any natural ore on Earth should ever have.

[00:00:35]Something had already consumed [music] it.

[00:00:38]Nobody could explain it.

[00:00:41]The missing uranium was enough [music] to build six atomic bombs.

[00:00:45]Regulators feared theft.

[00:00:47]They were wrong.

[00:00:49]Isotope analysis [music] revealed the truth.

[00:00:52]The rock itself had run a self-sustaining nuclear chain reaction.

[00:00:57]Pulsing.

[00:00:58]Cycling.

[00:01:00]For 150,000 years.

[00:01:03]Groundwater moderated the reaction.

[00:01:06]Every 30 minutes it boiled away.

[00:01:08]Every 2.5 hours it returned.

[00:01:12]The reactor breathed.

[00:01:14]By itself.

[00:01:16]It couldn't happen today.

[00:01:18]Earth has changed.

[00:01:20]But once our planet ran a nuclear reactor and nobody knew.