Waterworlds. Can There Be Life Without Land?
One of the longstanding questions astronomers have had is, are we normal? Is our Solar System a template for what we might expect to see as we look out into the Milky Way at other star systems?
As the data continue to come in, the answer to that question really seems to be no, we’re not normal. Star systems seem to have a huge variety of planets orbiting them. Familiar planets like our own terrestrial, gas and ice worlds. But then there are also super earths, mini-neptunes, hot jupiters.
And it looks like there are planets, located in their star’s habitable zone, which are completely covered with liquid water. Like, oceans which are dozens and maybe even hundreds of kilometers deep.
What would it be like on one of these worlds, and of course, we always want to know, could they be habitable?
Comments (1)
If our Goldilocks Zone plus 24% surface land planet (that can launch space missions, assuming suitable technology and surface gravity) isn't normal, SETI needs to be rethought in a major way. We can still likely detect life in a few decades through a combination of habitable zone and finding multiple molecules likely indicating atmospheres and life as we choose to recognize it. Direct images would be even better-Green, brown, and Purple planet mugs and calendar sales would be one way to fund exobiology research. (Sign me up!) We also need to recognize we might find Zombie Planets (false positives) or Cryptic Life (false negatives) Planets. We keep assuming life would be everywhere on a planet. That might be too optimistic. What if there was life only in say one cave complex or enormous salt dome? That might not provide enough outgassing to the atmosphere (assuming there is one) to give a signature we can find. Mars and our icy bodies are our best exemplars. A Ceres landing should be a priority, with a sterilized, next generation approach that can sample for chemistry, and fly an electron microscope. Ceres is much closer than Europa, data return is easier, gravity is less of a problem than landing on Mars, and this is a test bed for the more expensive Jupiter/Saturn missions.