Instead of cave dwellers gathered around a campfire, roasting mastodon meat, imagine an octopus tribe floating around a hydrothermal vent at the seafloor, boiling lobsters.
That’s the scenario sketched out by Dirk Schulze-Makuch, an astrobiologist at Germany’s Technical Institute Berlin who’s also an adjunct professor at Arizona State University and Washington State University.
In an essay published today on Smithsonian Air and Space magazine’s website, Schulze-Makuch notes that a fair number of potentially habitable planets could have surfaces completely covered by oceans. Could life arise on such planets? And if so, how technologically advanced could such species become?
Earth’s oceans provide an example in the form of cephalopods. Octopuses and squid are thought to have evolved strictly in the oceans, in contrast to dolphins and whales, which spent part of their evolutionary history on land. Octopuses are also arguably tool users, based on what they can do with coconut shells.
Under the right conditions, could such water-dwelling creatures develop technology on an alien water world? That may be more challenging than it was for our forebears, Schulze-Makuch says.
“Fire can’t exist underwater, and fire is thought to have been essential for humans to develop technology,” Schulze-Makuch notes. However, there’s one potential avenue that he and co-author William Bains explore in their book, “The Cosmic Zoo: Complex Life on Many Worlds.”
“Perhaps smart ocean creatures could use thermal vents on an alien planet’s seafloor to supply concentrated heat energy,” Schulze-Makuch says. “Such energy wouldn’t be as portable or controllable as fire, but the underwater civilization could farm fish without fire, or perhaps use other resources to make tools and technology. As an example, long strands of kelp could be ideal for making rope.”
The prospect of finding life on water worlds isn’t merely a matter for science-fiction speculation: Astrobiologists suspect that hydrothermal activity could support life within the hidden oceans of Europa and Enceladus, ice-covered moons that orbit Jupiter and Saturn.
Who knows? Perhaps future missions such as NASA’s Europa Clipper could detect the waste ejected by life forms beneath the ice — just as future alien archaeologists will be able to tell we existed after we’re gone, based on the plastic waste we’re leaving behind in Earth’s oceans.