2026-04-02
6 分钟NPR.
This is The Indicator from Planet Money.
I'm Darian Boyds.
Recently, I got a postcard from Alex Mayasi, contributor to Planet Money.
Dear Darian.
It was from the cesium fountain atomic clocks in Colorado.
These are the clocks that set time for wristwatches, wall clocks, and phones all across the country.
These atomic clocks are examples of public goods.
A public good is some service or benefit that you can't exclude people from.
So the whole world benefits from atomic clocks.
They help us set the time better.
Also, more people benefiting from the public good doesn't take away from others.
So you can talk about things like streetlights or national security as being public goods.
These atomic clocks measure the length of a second by the resonant frequencies of atoms.
They are the world's most accurate type of clocks.
The ones here are some of several hundred around the world, used to coordinate time for everyone.
Without such accurate shared time, GPS locations would be off,
internet errors would proliferate, and power grids could fail.
Clocking out for now, Alex.
Alex Mayasi is also the author of the new Planet Money book.