It’s no wonder that scientists are clamoring to find evidence of extraterrestrial life. So far, they have not located a single planet with significant oxygen in its atmosphere. Scientists have found small concentrations of molecular oxygen on Mars, Venus, and Jupiter’s moon Europa. None of these findings indicate that any of these locations are capable of harboring life, at least as we understand it. Astrobiologist Lewis Dartnell and astronomer Seth Shostak offer their insights into the complex requirements for a technical revolution beyond Earth.
Dartnell, author of "The Knowledge: How to Rebuild Our World from Scratch," suggests that for aliens to achieve a technological breakthrough akin to Earth's industrial revolution, they would need an energy source as bountiful as fossil fuels. We asked Adam why he focused so much on the scientific importance of plate tectonics for the development of life. It helped get and keep Earth’s climate hospitable for life.
The Role of Plate Tectonics
In Dartnell’s opinion, plate tectonics are essential to understanding how life forms would develop and evolve. In 2022, scientists at the University of Sydney measured the benefit. In doing so, they found that Earth’s tectonic plates are key actors in delivering carbon from the deep Earth to the surface. This natural process is the key to keeping Earth’s “Goldilocks” climate— not too hot, not too cold— that allows our planet to support life as we know it.
"Prior to that, energy was the fundamental limitation on how much you could do," said Dartnell, reflecting on Earth's historical reliance on energy sources.
This announcement highlights the similarities between planetary history on Earth and what we might need to look for in extraterrestrial civilizations. Industrial revolution that began in the 18th century continues to carry mankind downstream to unprecedented shores of prosperity. It tapped into what seemed like a limitless source of power.
Exploring Alternative Energy Sources
What kinds of energy might exist for these civilizations so far from home? Even there, he points out, hydropower would only be feasible under certain strict conditions. He claims that liquid currents of great volume and accessibility would be absolutely mandatory in order for hydropower to perform successfully.
Hydrogen makes up about 75% of the universe’s mass, added Shostak. This relative abundance of hydrogen further implies that it may be a useful energy source for extraterrestrial life. Tapping into this massive resource would demand cutting-edge technology and a plethora of other factors that make its use possible.
"It's hard for us to predict what the aliens might do," Shostak commented, highlighting the complexities involved in speculating about extraterrestrial ingenuity.
Wind energy is helping to power an alien civilization’s energy needs. This will not be sufficient for high-temperature processes, including the smelting of metals, Dartnell asserts. This limitation only adds to the importance for diverse and abundant energy supply.
Liquid Hydrocarbons on Titan
Surprisingly, scientists have found an entire sea of liquid hydrocarbons on Saturn’s moon Titan. This finding provides new opportunities for energy reservoirs beyond traditional planetary systems. Just because there could be hydrocarbons doesn’t mean they’ll have an energy source even in the same league as fossil fuels on Earth.
This is because, ultimately, overcoming energy limitations is a necessity for any civilization that wishes to develop technologically. Dartnell and Shostak’s understanding suggests complex interplays of geological processes, atmospheric conditions, and resource availability.
