What do you think are the odds that you will die during the next year? Try to put a number to it — 1 in 100? 1 in 10,000? Whatever it is, it will be twice as large 8 years from now.

This was first noticed by the British actuary Benjamin Gompertz in 1825 and is now called the “Gompertz Law of human mortality“. Your probability of dying during a given year doubles every 8 years.

[T]he Gompertz law holds across a large number of countries, time periods, and even different species. While the actual average lifespan changes quite a bit from country to country and from animal to animal, the same general rule that “your probability of dying doubles every X years” holds true. It’s an amazing fact, and no one understands why it’s true.

Fascinatingly, cancer rates also exactly follow Gompertz’s Law, another support in the increasing amount of evidence accumulated over the last couple of decades that aging and mortality are somehow programmed into our genes.

“How” is certainly a good question, but so is “Why”. Particularly interesting about the latter question is that the answer does not require a geneticist’s expertise to speculate about.

Evolution adapts species to fit their environment, so anything like this that is programmed in – particularly since it appears to be across species and millions of years – has to have a very good reason, perhaps simply maintaining a sufficiently fast speed of adaptation. After all, evolution necessity doesn’t actually give a crap about you as an individual, but it cares quite a bit about your species as a whole.

Top image via mjranum-stock on deviantART.
Via Brian Skinner.