Life may have emerged from an underwater chimney that percolated eons ago. If that’s true, a similar setup on ocean worlds in our Solar System like Jupiter’s moon Europa or Saturn’s moon Enceladus could have sprouted alien life.
These chimneys are called hydrothermal vents. Miraculously, life exists (and even thrives) in their extreme environments. Over several decades, scientists have made incredible discoveries about them. A new project could enable us to study these vents like never before by bringing the laboratory to the sea.
InVADER, short for In-situ Vent Analysis Divebot for Exobiology Research, is designed to, ultimately, reveal if hydrothermal vents are where life emerged on Earth. By bringing its laser technology to the sea floor, measurements can be faster, cheaper, and in some ways, more accurate.
Before, scientists had to fish samples out of their local environment and haul them across oceans to a laboratory, all while time and distance could alter the samples.
“InVADER is essentially the first laser sensor that is able to scan the rocks, that is able to analyze biological diversity … and is also able to analyze the fluids that come out of these chimneys,” Pablo Sobron, Search for Extraterrestrial Intelligence (SETI) Institute research scientist and InVADER project lead, tells Inverse.
Sobron is currently at sea onboard the E/V Nautilus validating InVADER’s instrumentation. Once this premiere mission over the Pacific Ocean is complete, InVADER will be readied for one year of daily on-site observations near a known hydrothermal vent off the coast of Oregon, Sobron says.
What are hydrothermal vents?
Almost half a century ago, a robotic mini-submarine called Alvin discovered something bizarre more than 8,000 feet beneath the surface of the Pacific Ocean. When its companion scientific apparatus ANGUS noticed a sudden spike in temperature in the otherwise frigid depths through which it was cruising, scientists checked ANGUS’ photos. They were shocked that in the barren seafloor, life seemed to be teeming near a previously-undiscovered heat source. As Alvin drew closer to investigate, its three-person crew ended up discovering the first hydrothermal vent.
Hydrothermal vents form when water creeps deep into fissures near tectonic plate fault lines, and super-heats. With the weight of the ocean on top, the hot water cannot boil away. Instead, it billows up and out, gets shocked by the almost freezing water around it, and releases an assortment of minerals that precipitate and grow the vents, which look like tall candles whose wax has melted.
Since the momentous discovery of 1977, researchers have directed robotic pincers to pull up biology samples from the chimney environment, including large clams and tubular worms, so they could be analyzed in laboratories.
In 1980, Colleen Cavanaugh discovered bacteria had been living in the gut of tube worms, where it turned the hydrothermal vent’s byproducts into food for the worms, all without sunlight. But the vents’ “hot soup,” as Sobron calls it, is still a big puzzle. There are fine tubes within the vents called microchannels where life takes hold super quickly, he says, which scientists know from looking at samples under the microscope.
But the ocean has life everywhere, and it’s unknown if vents attract life that already exists in the deep blue sea, or if the vents have conditions where life may have once formed spontaneously.
What vents may reveal about the origins of life on Earth could transform how we perceive the subsurface oceans deep below the icy shells of several Solar System moons. Jupiter’s moon Europa is one of the best candidates for alien life, whose churning subsurface ocean is in contact with a rocky layer below it where vents might exist. Saturn’s moon Enceladus is rich with salt water, which a series of geysers spray out as vapor plumes.
Not only does Saturn’s moon Titan have a subsurface ocean, it also has standing bodies of liquid and a hazy atmosphere. Jupiter’s moon Ganymede is the largest and most robust moon in the Solar System, and even boasts its own magnetosphere, a feature on Earth that helps to shield life forms from harmful radiation.
If life once appeared spontaneously from Earth’s hydrothermal vents, maybe it could have emerged in the subsurface oceans buried deep below the icy exteriors of these Solar System moons. Maybe the recipe for life isn’t exclusive to Earth.
How InVADER Will Help Find Life
InVADER’s big offer is that it can fill in gaps in knowledge. This sealab’s constant measurements will reveal what happens on shorter timescales, and help paint an idea of what’s happening that other periodic or sporadic analyses might have missed.
“There are cameras looking at chimneys, you know, for months and years at a time. We know that. There have been, of course, bio investigations, chemical investigations with certain in-situ instruments [but that] have only been done one time or two times over years of spacing between those measurements,” Sobron says.
“So what we’re missing is what are the kinetics, what is the change in dynamics of this, you know, on a daily basis, on a weekly basis, on a monthly basis. [In 2024] that’s the first time we’re going to be able to do lab-like analysis on a vent daily essentially for over a year.”
For all we know about these chimneys, there is a lot that is unknown. This is especially true when it comes to life at extremes. But given the extremes that might be found on ocean worlds like Europa and Enceladus, we’re only at the beginning of our pursuit of alien life.