# Who decides how long a second is? - John Kitching

Page: https://stenobird.com/podcast/ted-ed-7859430/who-decides-how-long-a-second-is-john-kitching
Text version: https://stenobird.com/podcast/ted-ed-7859430/who-decides-how-long-a-second-is-john-kitching.md
Podcast: [TED-Ed](https://stenobird.com/podcast/ted-ed-7859430)
Published: 2026-07-07T00:37:00+00:00
Episode link: https://traffic.megaphone.fm/VG1024492575.mp3
Audio file: https://traffic.megaphone.fm/VG1024492575.mp3
Processing state: not_requested
JSON: https://stenobird.com/v1/public/podcasts/ted-ed-7859430/episodes/who-decides-how-long-a-second-is-john-kitching
Duration seconds: 511

## Resource

Discover how scientists developed atomic clocks, which use the vibrations of atoms to measure and maintain a globally consistent time. --In 1967, researchers gathered to answer a long-running scientific question: just how long is a second? It might seem obvious at first. A second is the tick of a clock, the swing of a pendulum, the time it takes to count to one. But how precise are those measurements? And what is that length based on? John Kitching digs into how we scientifically define this fundamental unit of time.Lesson by John Kitching, directed by Tjoff Koong.Support Our Non-Profit Mission----------------------------------------------Support us on Patreon: http://bit.ly/TEDEdPatreonCheck out our merch: http://bit.ly/TEDEDShop----------------------------------------------Connect With Us----------------------------------------------Sign up for our newsletter: http://bit.ly/TEDEdNewsletterFollow us on Facebook: http://bit.ly/TEDEdFacebookFind us on Twitter: http://bit.ly/TEDEdTwitterPeep us on Instagram: http://bit.ly/TEDEdInstagram----------------------------------------------Keep Learning----------------------------------------------View full lesson: https://ed.ted.com/lessons/who-decides-how-long-a-second-is-john-kitchingDig deeper with additional resources: https://ed.ted.com/lessons/who-decides-how-long-a-second-is-john-kitching#digdeeperAnimator's website: http://greenhouseanimation.com/directors/tjoff-koong/----------------------------------------------Thank you so much to our patrons for your support! Without you this video would not be possible! Po Foon Kwong, NinjaBoffin, Jesse Jurman, Josue Perez Miranda, Scott Markley, Elija Peterson, Ovidiu Mrd, Lawrence Wu, Xavier Dupont, Aravind Battaje, Nathan Giusti, Helen Lee, Anthony Benedict, Karthik Balsubramania…

## Actions

- request_transcript: `POST https://stenobird.com/v1/public/podcasts/ted-ed-7859430/episodes/who-decides-how-long-a-second-is-john-kitching/transcription-requests` — Idempotently request low-priority transcript generation for this episode.
- read_markdown: `GET https://stenobird.com/podcast/ted-ed-7859430/who-decides-how-long-a-second-is-john-kitching.md` — Read the agent-friendly Markdown representation of this episode resource.

A page view does not enqueue transcription. Agents should invoke `request_transcript` explicitly when they need this episode processed.

## Transcript

Full transcripts are not published on public pages unless there is a clear rights basis.