{"api_version": 1, "episode_id": "ep_radiolab_9172cbe5d5e2", "title": "\u2264 kg", "podcast": "Radiolab", "podcast_slug": "radiolab", "category": "science", "publish_date": "2014-06-13T15:24:37+00:00", "audio_url": "https://pscrb.fm/rss/p/mgln.ai/e/14/prfx.byspotify.com/e/dts.podtrac.com/pts/redirect.mp3/waaa.wnyc.org/758af4c0-a2c3-47ec-a2d8-05f41bfbde51/episodes/d1d64629-2b17-4e35-9af0-005f8d8768ed/audio/128/default.mp3?aid=rss_feed&awCollectionId=758af4c0-a2c3-47ec-a2d8-05f41bfbde51&awEpisodeId=d1d64629-2b17-4e35-9af0-005f8d8768ed&feed=EmVW7VGp", "source_link": "https://www.radiolab.org", "cover_image_url": "https://image.simplecastcdn.com/images/758af4/758af4c0-a2c3-47ec-a2d8-05f41bfbde51/d1d64629-2b17-4e35-9af0-005f8d8768ed/3000x3000/massstandards-024.jpg?aid=rss_feed", "summary": "The episode traces the history and fragility of the kilogram, the last physical standard of measurement, which was defined by a platinum-iridium cylinder in France. It reveals how, in 1989, the international prototype kilogram was found to have lost mass relative to its official copies, undermining its role as an unchanging standard. The episode culminates in the scientific effort to redefine the kilogram using the Planck constant, anchoring it to a fundamental physical constant rather than a physical object.", "key_takeaways": ["The kilogram was historically defined by a physical object\u2014the International Prototype Kilogram (IPK)\u2014stored in France, which served as the standard for all mass measurements worldwide.", "In 1989, scientists discovered the IPK had lost approximately the mass of a grain of sugar compared to its official copies, raising concerns about the stability of a physical standard.", "The kilogram is now redefined by fixing the value of the Planck constant, making it invariant and based on fundamental physics rather than a deteriorating artifact."], "best_for": ["science enthusiasts", "physics educators", "history of science students"], "why_listen": "It transforms a seemingly mundane unit of measurement into a profound narrative about human precision, the fragility of standards, and the shift from physical artifacts to universal constants in science.", "verdict": "must_listen", "guests": [], "entities": {}, "quotes": [], "chapters": [], "overall_score": 85.0, "score_breakdown": {"clarity": 90.0, "originality": 85.0, "actionability": 50.0, "technical_depth": 88.0, "information_density": 90.0}, "score_evidence": {"clarity": "The definition of a kilogram is the mass of the international prototype kilogram.", "originality": "We got a hunk of metal losing weight, and yet because it is the standard It still weighs exactly a kilogram.", "actionability": "You can't do that. And then everything else in the world is wrong.", "technical_depth": "The new definition of the kilogram... fixing the numerical value of the Planck constant to be equal to exactly 6.626069...", "information_density": "Roughly the mass of a grain of sugar. Oh. Yeah. So Is that gigantic? It's measurable."}, "score_reasoning": {}, "scoring_confidence": 0.95, "transcript_available": true, "transcript_chars": 20975, "transcript_provider": "deepgram"}