The article explores how exchange rates between countries can change over time. By looking at 40 different exchange rates, the researchers found that most of them stay stable for around 60 years. This means that the value of money in different countries doesn't always equalize quickly like some studies suggest. Instead, it can take anywhere from 1 to 40 years for exchange rates to balance out. This shows that the way exchange rates work in reality may be different from what many people think.