Last April, we speculated about the possibility of extraterrestrial life underneath the dwarf planet Pluto’s icy surface. As the New Horizons mission closes in, the prospect of microbial life on Pluto—and its largest satellite, Charon—seems increasingly plausible. Why? Because we’ve discovered that both bodies have the key ingredients that have made the possibility of life seem so strong on Europa and Enceladus: ice and heat.
The discovery of Pluto’s ice cap over the weekend wasn’t much of a surprise, but the planet’s complex geological features suggest that it may, in fact, be geologically active. And as we noted last June, a geologically active planet with ice caps may very well have pockets of warm liquid water underneath the surface—not necessarily proof of life, but certainly proof that an environment exists that may be friendly to life. New Horizons data also suggests that the case for a geologically active Charon is very strong, with a surface that has been torn apart and may actually feature not only ice, but also ammonia-contaminated liquid water.
Life on Pluto and Charon, if it exists at all, is unlikely to be very advanced. But that’s not really the point; the point is that the outer solar system is likely to contain hundreds of bodies of similar composition, and the confirmation of life on Pluto or Charon, in any form, would suggest that microbial life in our solar system is abundant. Those would give us some very favorable numbers to plug into the Drake equation, and increase the odds that complex, intelligent life might one day be found elsewhere.