German astronomer and mathematician Friedrich Bessel managed to successfully measure the distance from Earth to a star other than our sun in the 19th century. But he realized that his measurements meant nothing to people as they were. They were too abstract.
So he came up with the idea of a “light-year” to help people get a better understanding of just how far it really is.
And rather than using a measurement of distance, he chose to use one of time. The idea was that since we—or at least scientists—know what the speed of light is, by representing the distance in terms of how long it would take for light to travel that distance, we might be able to comprehend that distance.
Ultimately using a metric we are familiar with to understand one with which we aren’t.
Why don’t we try to do the same with another thing in the universe that’s incomprehensibly large today—the debt of the US government?