Life on earth dates back some 3 billion years, a pretty long time considering that we, as humans, have existed for roughly 200,000 years. But could intelligent life have existed before human life? An intelligent species before us capable of complex thinking? In this article we will discover it for you
The beginnings of life on earth
In the early days of life on earth, this was only at the cellular level; And although microscopic, it was powerful enough to dominate the planet for 2.4 billion years, until the first living things began to emerge in the water. Among the first were the jellyfish, which had no legs, not even a brain, so life had not reached the earth as such. This did not happen until 350 million years ago, a crocodile seal-like species called Ichthyostega appeared. These animals began an evolutionary chain that would link dinosaurs, mammals, and all life on earth, including humans.
Are there signs of intelligent life before human life?
Sixty-six million years ago, a large asteroid destroyed the dinosaurs, throwing debris into the atmosphere and depriving plants of the ability to photosynthesize. This actually damaged the food chain, so much so that more than 80% of all life disappeared, and very few species managed to survive.
Surprisingly, life on earth took a fairly rapid turn around 30,000 years later. This post-dinosaur period is especially interesting due to the climatic conditions, which were extremely similar to ours today.
Climate change and the greenhouse effect
Through the scientific discovery of rocks dated more than fifty-five million years ago, we can know that there was a colossal increase in the amount of CO2 that was released into the atmosphere in a short space of time. Something similar to what is happening to him on earth right now.
As the fossil records show, this acidified the oceans in a short period of time, and the fact that this was correlated with a large amount of greenhouse gases, links this situation very strongly with the one we face today.
Over the next thirteen years, this huge excess of CO2 caused severe global warming, known as the Paleocene-Eocene Thermal Maximum. The poles reached temperatures of 12º C, while in the equator the average temperature reached 60 degrees Celsius throughout the year.
These facts represent the probability that there was life on earth before humans between the dinosaurs and this “Thermal Maximum” period in the form of an intelligent species, and that it faced a fate similar to that of humans today.
The Silurian hypothesis
A seemingly strange but quite reasonable question may then be posed: is it possible that some other intelligent species existed on earth, in the distant past, and created an industrial civilization somewhat analogous to ours? And from this question immediately arises another: if there ever was another industrial civilization, what geological traces do we have today to prove its existence?
The second question has guided the work of two scientists, Gavin A. Schmidt, a climatologist and director of the Goddard Institute for Space Studies (GISS), and Adam Frank, a professor of astrophysics at the University of Rochester. His answer is in a study published in April 2018 in the International Journal of Astrobiology: “The Silurian hypothesis” , a term that refers to an episode of the science fiction series Doctor Who, broadcast in 1970, in which it is spoken of a species of intelligent reptiles, that would have lived, dominated and perished on earth after altering it enough to destroy it.
The numbers add up: there was time for intelligent life to develop before human life
Although the authors of the study do not believe that a reptilian species existed as such prior to the human species, they do maintain the hypothesis that, according to geological readings, there could be intelligent life before human life; and that, as we seem to be done slowly, this species brought the planet to its decline due to the exploitation of resources and did not manage to survive.
Apparently, they would not have been able to keep carbon out of the atmosphere, because the CO2 dissolved in the oceans, causing them to become increasingly acidic, killing more deep-sea species than the asteroid that killed the dinosaurs.; and, in principle, it took 150,000 years for things to return to normal.
As it only took humans 200,000 years to become a species capable of manipulating the surrounding landscape into energy, and 5 million years to evolve from a monkey, this theoretical species would have had enough time to develop between the death of dinosaurs and the Paleocene-Eocene Thermal Maximum period, with a life very similar to ours.