In high school, I learned that absolute zero (about -460° Fahrenheit or -273° Celsius) is as cold as you can get. At that point, all motion ceases, and you can’t get any colder.
So it was a bit of a head-scratcher to learn that physicists recently created a gas whose temperature is below absolute zero. Seems impossible, right?
Well, no. Turns out that the high-school definition of absolute zero doesn’t capture the modern notion of temperature. As Empirical Zeal explains, temperature isn’t only about motion, it’s about an object’s willingness to give up energy. And physicists have been creating negative-temperature objects for more than 60 years.
Measurement is a recurring theme on this blog, so I found this intriguing. All those years, and I didn’t actually know how physicists really measure temperature. But what really caught my eye is that Empirical Zeal uses some ideas from economics to explain what negative temperatures are all about.
Using the ideas of exchange, marginal utility, and utility maximization, he illustrates how negative temperatures are like a world in which the Dalai Lama should give all his money to Warren Buffett.
I can’t do justice in an excerpt, so please click on over if you are interested.