What is the Silurian Hypothesis

Would we recognize the traces of a sunken dinosaur civilization?

Rochester - In the "Distant Origin" episode of the TV series "Star Trek: Voyager", the crew of Voyager encounters the space-traveling descendants of hadrosaurs. They had once founded a high civilization on earth, only to settle into the vastness of the galaxy before the global catastrophe 66 million years ago.

A team of astrobiologists has now used the motif of earthly civilizations before the human era, which appears again and again in science fiction, as the starting point for a mind game. This was published as one of the more unusual papers of the week in the "International Journal of Astrobiology".

The Silurian Hypothesis

Adam Frank from the private University of Rochester and Gavin Schmidt from the Goddard Institute for Space Studies at NASA refer to the idea of ‚Äč‚Äčintelligent dinosaurs as an example, but think in even larger time frames: After all, their "Silurian hypothesis" refers to the Silurian Age 443 to 419 million years ago.

However, the subject of the hypothesis is not the assertion that such a civilization existed - the researchers even hasten to clarify that there is no evidence whatsoever for such a thing. Rather, they want to investigate the question of whether and which geological traces an industrial civilization like ours would leave behind. Ultimately, your paper is part of the current research discussion about the properties and consequences of the Anthropocene, the human-shaped geological age.

Overall, the geological heritage of a civilization would at first glance only differ slightly from the layers above and below, the researchers conclude. It is difficult to separate natural from artificial influences afterwards. With a view to today, Frank and Schmidt believe they can filter out some factors that are typical of a civilization with high energy requirements.

Pay attention to the isotopes

One of the examples from our era is the massive consumption of fossil energy sources: This has already changed the global carbon cycle in such a way that this can be seen in the distribution of carbon isotopes. Large-scale agriculture has not only accelerated erosion, it has also disrupted the nitrogen cycle through the use of fertilizers.

In addition, there are man-made substances from plastic to steroids, which, once put into circulation, would still be detectable in geochemical analyzes millions of years later - possibly billions, according to the researchers. And if you include the possibility of using nuclear weapons, that would again leave conspicuous isotope distributions behind.

A high civilization leaves its chemical legacy behind: Corresponding analyzes should be included in future planetary explorations, says Schmidt - even if the examples of Mars and Venus he cited are not really convincing: Mars only had a relatively short window of time in which it was friendly to life could, and in the case of Venus this is even more uncertain.

Bottom line

An ironic conclusion from their hypothesis, according to Schmidt, is that in this way one would only find traces of failed civilizations: They would have briefly blossomed through their massive interventions in nature, but soon perished again for the same reason. Cultures could only have survived in the long term if they had learned to deal with their home planet in a sustainable manner. Then, however, one would hardly find traces of them in later ages.

In the event that our own civilization fails, Frank has to offer a sober consideration as "consolation": The earth itself will continue to exist. "It's not about 'saving the earth'", says Frank. "No matter what we do to the planet, we are just creating niches for the next cycle of evolution. But if we continue on our current path, we humans may no longer be part of this ongoing evolution." (jdo, April 21, 2018)