Kepler 538-b is larger than Earth, and has a much higher temperature, but it still falls within the realm of potentially habitable. But that rarity points to another important finding from the paper - Earth is a statistical rarity in terms of planets, but not one that requires some miraculous confluence of planetary and stellar characteristics. Using a statistical technique called the Mahalanobis distance analysis, the authors found that Earth is around 69.4% different in terms of “statistical unusualness”, making it rare, but not too rare.

As the science of astrobiology and exoplanets moves forward, continuing this type of statistical analysis will provide valuable context that could otherwise mislead or obfuscate the areas that have the most potential to answer one of the most important questions to humanity - are we alone? With increasingly powerful observational equipment pointed in the right direction, we might soon have a definitive answer to that question.