Lee Billings has a fascinating article up at Aeon asking why we continue to send missions to Mars when the best chance of life existing today is in Europa’s underground ocean.
If Europa is alive, if some biology dwells within those dark waters, the implications would be even more staggering than finding life on Mars. Our gaze would turn to Jupiter’s Ganymede next, and to Callisto, along with Saturn’s Titan and Enceladus, and perhaps even the dwarf planets such as Ceres and Pluto, all of which also likely harbour substantial subsurface reservoirs, heated through some combination of tides and radioactive decay.
And if water and life could exist there, why not in the hearts of large comets, before the Sun’s planets and moons even finished forming? Our solar system might have brimmed with hidden life for nearly as long as the Sun has shined, and ice-roofed worlds might be the default abodes for biology in the Universe. Life within a roofed world could proceed swimmingly against any number of otherwise-fatal cosmic calamities, whether being slingshotted into the interstellar dark as a rogue planet, or being bathed in hard radiation from a nearby supernova or burping black hole. We could then guess why, like our solar system, the Universe at large looks so desolate to us. In this scenario, most life, even if it had eyes to see, would never glimpse sky, stars, light, or fire, and would have scant hope of ever reaching what lies above and beyond its icy shell.
I’ve highlighted what I considered to be the most mind blowing part of the article above, but I recommend the whole piece.
As Billings admits, the cost of exploring Europa is much higher than Mars. And Europa is a far harsher environment for us. But the possibility of life is much stronger. And the passage above makes me wonder if we shouldn’t be taking a closer looks at other places such as the large comets he mentions. Of course, all of this takes money.
The really mind blowing part though is the possibility that life might be much more prevalent in those types of environments. We tend to assume that Earth is typical, but there’s nothing to indicate that it is typical for life other than the Copernican principle, which although history has repeatedly validated it, it remains only a principal; past performance is no guarantee of future performance.