Have you ever wondered what it would be like if, millions of years after people left the Earth, some other animal species evolved to the human level of intelligence? We don't know about you, but we always liked to represent raccoons in this role.
Maybe in 70 million years a family of such cute animals will gather at the foot of Mount Rushmore, causing fire with a snap of their fingers and thinking about what kind of creatures the sculptures were carved on the slope (we are talking about the famous sculptural portraits of four US presidents: George Washington, Thomas Jefferson, Theodore Roosevelt and Abraham Lincoln)?
But wait, will Mount Rushmore live to see those infinitely distant times? What if we are the very raccoons? In other words, what if technologically advanced creatures dominated our planet during the era of the dinosaurs, and we simply don't have any evidence of their existence? And if not, how do we know it didn't happen?
Earth before time
This is called the "Silurian Hypothesis" (and lest you think badly about the scientists, it's named after the aliens from Doctor Who). In principle, its essence is that humans may not be the first intelligent life form that evolved on this planet, and that if indeed our intelligent predecessors lived here about 100 million years ago, almost all traces of their civilization would have been lost by now. time.
In case you misunderstood, physicist and co-author Adam Frank clarified the situation in an article in the Atlantic magazine: "You don't often have to write a paper that puts forward a hypothesis that you don't support." In other words, scientists really do not believe in the existence of the ancient civilization of the Time Lords or lizard people. The goal of the researchers was different: to invent ways that would help us find signs of ancient civilizations on other planets.
It may seem obvious that we would easily see evidence of such a civilization. After all, dinosaurs lived 100 million years ago, and we know a lot about them since their fossils were found. But they have existed for 150 million years. This is important because it's not just how old the remnants of a hypothetical civilization are, and not how widespread it was across the planet. It's also about how long it has existed. Humanity has spread over an unusually short span of time, in just 100,000 years. If we assume that the same thing happened to another species of intelligent creatures, our chances of finding it in geological layers would be negligible. Frank and his co-author Gavin Schmidt report on methods of detecting ancient civilizations.
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Needle in the haystack of time
There is probably no need to remind us that humanity is already having a lasting impact on the planet. Even when our civilization disappears, the plastic will disintegrate into microparticles, which form sedimentary rock for researchers who will come one day in search of its traces. But while these traces can last for quite some time, it is difficult to expect a microscopic layer of plastic debris to be found. Instead, it would be much more appropriate to look for traces of periods of increased carbon content in the atmosphere.
It is believed that now our planet is in the Anthropocene period, which is characterized by the widespread and dominance of human civilization. It is also characterized by an unprecedented surge in the concentration of carbon in the air. This does not mean that there is more carbon in the atmosphere now than ever before.
About 56 million years ago, the Earth passed through the Paleocene-Eocene thermal maximum, a period of extremely high temperatures across the entire surface. It is about 21 degrees Celsius at the poles. This period corresponds to an increase in the amount of fossil carbon in the air, and the exact reasons for this phenomenon are not yet fully understood.
Was this an ancient civilization? In short: no, nothing like that, don't be funny. This increase in carbon in the earth's atmosphere has continued for a couple hundred thousand years. The current peak lasts only 300 years.
The takeaway from this astonishing study is that there is actually a way to find ancient civilizations. All one has to do is look for signs of short, sharp surges in carbon concentration in the ice crust, but unfortunately, this “needle” in a haystack is very easy to miss if researchers don't know exactly what they are looking for.
Svetlana Bodrik