June 5, 2024 • 21min
The history of light (classic)
Planet Money
Key Takeaways
- For thousands of years, getting light was an extremely difficult and labor-intensive process, requiring things like rendering animal fat into candles.
- The history of light is closely tied to the history of economic growth - as light became cheaper and more efficient, it enabled new industries, technologies, and ways of living to emerge.
- Economist Bill Nordhaus calculated that in ancient Babylon, a day's wages could only buy about 10 minutes of light from a primitive lamp. By the 1990s, a day's wages could buy 20,000 hours of electric light.
- Key innovations like kerosene lamps and electric lighting dramatically reduced the cost and increased the availability of light, fueling broader economic and social progress.
- The story of light illustrates how economic growth happens through a constant process of small improvements and innovations, rather than just major breakthroughs.
- While economic growth has brought many benefits, it has also come with tradeoffs like increased pollution from early power plants.
- The pace of innovation in lighting may be slowing as we approach physical limits, raising questions about whether economic growth can continue indefinitely.
Introduction
This episode of Planet Money explores the history of how humans have captured and used light over the centuries, and how this history is closely tied to the broader story of economic growth and progress. Hosts Jacob Goldstein and David Kestenbaum trace the evolution from primitive candles made from animal fat to the ubiquitous electric lighting we have today.
The hosts highlight how the quest for better lighting drove all sorts of innovations, from using dried salmon as candles to catching and drying seabirds to use as lamps. They also note the immense amount of labor and resources required to produce even the most basic forms of light in the past.
The episode then dives into the work of economist Bill Nordhaus, who set out to quantify the cost of light over the centuries. His findings illustrate just how dramatically the cost and availability of light has changed, and how this mirrors broader economic transformations.
Topics Discussed
The Difficulty of Producing Light in the Past (1:44)
- For thousands of years, producing light required rendering animal fat into candles, an incredibly labor-intensive process.
- People used all sorts of creative but impractical methods, like dried salmon, fireflies, and even stuffing a wick down the throat of an oily seabird.
- Making candles from animal fat was described as "seven times as bad as washing clothes" by writer Harriet Beecher Stowe.
Measuring the Cost of Light Over Time (8:15)
- Economist Bill Nordhaus set out to calculate the cost of light over thousands of years, from ancient Babylon to the modern era.
- In ancient Babylon, a day's wages could only buy about 10 minutes of light from a primitive lamp.
- By the 1800s, kerosene lamps provided about 5 hours of light per day's wages, a major improvement.
- By the 1990s, a day's wages could buy around 20,000 hours of electric light, reflecting dramatic increases in efficiency and affordability.
The Role of Science and Innovation (12:11)
- The pace of lighting innovation accelerated in the 1800s as the rise of professional science and experimentation enabled breakthroughs.
- The development of kerosene in the mid-1800s was a major turning point, providing a much brighter and cheaper light source.
- However, Edison's invention of the electric light bulb was not enough - he also needed to build an entire power plant infrastructure to make electric lighting viable.
The Broader Economic Impacts (19:47)
- Improvements in lighting enabled broader economic and social changes, like the rise of nightlife and reduced need for manual labor.
- While growth brought benefits, it also had negative consequences like increased pollution from early power plants.
- Overall, the history of light illustrates how economic growth happens through a constant process of small innovations and productivity gains.
The Future of Lighting Innovation (21:54)
- Experts suggest the pace of lighting innovation may be slowing as we approach physical limits, raising questions about the long-term sustainability of economic growth.
- Companies like Cree are still working to incrementally improve LED lighting, but major breakthroughs may be harder to come by.
Conclusion
The history of light is a powerful lens through which to view the broader story of economic progress and growth. Over thousands of years, the quest for better lighting drove all sorts of innovations, from primitive candles to kerosene lamps to electric power. Each step along the way enabled new industries, technologies, and ways of living to emerge.
Economist Bill Nordhaus' research quantified just how dramatically the cost and availability of light has improved, with a day's wages in the 1990s buying 20,000 hours of electric light compared to just 10 minutes in ancient Babylon. This mirrors the broader trajectory of economic growth, where constant small improvements and innovations compound over time.
While this progress has brought many benefits, it has also come with tradeoffs like increased pollution. And as we approach physical limits, the pace of lighting innovation may be slowing, raising questions about the long-term sustainability of economic growth. Nonetheless, the story of light remains a powerful illustration of how human ingenuity and the quest for progress have transformed the world.
