Summary
Overview
This Planet Money episode explores the economic history of light, from ancient candles to modern LED bulbs, as told through economist Bill Nordhaus's groundbreaking research. The episode demonstrates how productivity improvements and innovation have transformed our lives, using light as a case study to explain how economic growth works and why billions of people today don't have to worry about basic survival.
The Ancient Challenge of Making Light
For thousands of years, humans struggled to create light after dark, relying on burning fat from animals or other creative but difficult methods. Reporter Jacob Goldstein attempts to make candles from beef fat to illustrate just how labor-intensive this process was, spending hours hunting for ingredients and dipping wicks. The result demonstrates why pre-industrial societies lived primarily in darkness once the sun set.
- Before light bulbs, people used animal fat and wicks to create light for thousands of years
- Making candles from beef fat required extensive labor - raising cattle, extracting fat, and hours of dipping wicks
- Harriet Beecher Stowe said making candles from animal fat was seven times worse than washing clothes
" From an economic perspective, if you want to try to quantify how much of a pain in the butt it is to make something, or at least how hard it is to get that thing, you can ask a simple question. How much does it cost? "
Measuring the Cost of Light Through History
Yale economist Bill Nordhaus developed an ingenious method to track economic progress by calculating how much light people could buy with a day's wages across 4,000 years of history. He recreated ancient Babylonian lamps in his dining room and used a light meter to measure their output, discovering that in ancient times, a full day's work bought only 10 minutes of light equivalent to a modern bulb. This measurement reveals the fundamental poverty and limited productivity of pre-industrial societies.
- Nordhaus measured light costs across 4,000 years by asking: how many minutes of light could you get for a day's wages?
- In ancient Babylon, a full day's work bought only 10 minutes of light equivalent to a modern bulb
- Nordhaus found actual wage and price data from ancient Babylon dating back 4,000 years
- He recreated ancient lamps in his dining room and used a light meter borrowed from Yale facilities to measure brightness
" I did this in my dining room. Where else? "
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