Physicists including Robert H. Dickle and Fred Hoyle have argued that we are living in a universe that is perfectly fine-tuned for life. Following the anthropic principle, they claimed that the only reason fundamental physical constants have the values we measure is because we wouldn't exist if those values were any different. There would simply have been no one to measure them.

But now a team of British and Swiss astrophysicists have put that idea to test. "The short answer is no, we are not in the most likely of the universes," said Daniele Sorini, an astrophysicist at Durham University. "And we are not in the most life-friendly universe, either." Sorini led a study aimed at establishing how different amounts of the dark energy present in a universe would affect its ability to produce stars. Stars, he assumed, are a necessary condition for intelligent life to appear.

But worry not. While our Universe may not be the best for life, the team says it's still pretty OK-ish.

Back in the 1960s, Frank Drake, an American astrophysicist and astrobiologist, proposed an equation aimed at estimating the number of intelligent civilizations in our Universe. The equation started with stars as a precondition for life and worked its way down in scale from there. How many new stars appear in the Universe per year? How many of the stars are orbited by planets? How many of those planets are habitable? How many of those habitable planets can develop life? Eventually, you're left with the fraction of planets that host intelligent civilizations.

The problem with the Drake equation was that it wasn't really supposed to yield a definite number. We couldn't -- and still can't -- know the values for most of its variables, like the fraction of the planets that developed life. So far, we know of only one such planet, and you can't infer any statistical probabilities when you only have one sample. The equation was meant more as a guide for future researchers, giving them ideas of what to look for in their search for extraterrestrial life.