# Gott Mars? The human imperative to explore

How important is the human exploration of space? One argument take you're unlikely to hear in most debates over the wisdom of going to the stars involves a calculation by Dr. J. Richard Gott, a Louisville native, Princeton Astrophysicist and speaker at the IdeaFestival this September.

In 1993 he used the Copernican Principle to assess the odds for human survival and came up with the near certainty, statistically speaking, that humanity would go on for at least another 5,100 years.

The Copernican principle makes reasonable guesses about the future using one known fact and the assumption that there is nothing special about this moment in time. In 1969, Gott used the principle to accurately predict, for example, how long the Berlin Wall would stand.

John Tierney's New York Times article, "A Survival Imperative for Space Colonization" elaborates:

Suppose you want to forecast the political longevity of the leader of a foreign country, and you know nothing about her country except that she has just finished her 39th week in power. What are the odds that she’ll leave office in her 40th week? According to the Copernican Principle, there’s nothing special about this week, so there’s only a 1-in-40 chance, or 2.5 percent, that she’s now in the final week of her tenure.

It’s equally unlikely that she’s still at the very beginning of her tenure. If she were just completing the first 2.5 percent of her time in power, that would mean her remaining time would be 39 times as long as the period she’s already served — 1,521 more weeks (a little more than 29 years).

So you can now confidently forecast that she will stay in power at least one more week but not as long as 1,521 weeks. The odds of your being wrong are 2.5 percent on the short end and 2.5 percent on the long end — a total of just 5 percent, which means that your forecast has an expected accuracy of 95 percent, the scientific standard for statistical significance.

The "Space Colonization Imperative" suggests that humans should have a space colony up and running on Mars in the next 45 years, since, applying the Copernican principle, the space program is half way through its expected life span. If we don't have a permanent base on Mars by then, it might be too late.

His column also drew a response from one of my favorite writers on big space themes, Paul Gilster. His "Odds on a Human Future" post also describes Dr. Gott's thinking on the matter.

Wayne