If there is another civilization somewhere in space, it is almost surely much older than ours and has already managed to realize everything that we only dream of. Therefore, in order to find it, we must first understand our own possible future.
What we’ll be
One of the biggest problems in the search for extraterrestrial life is the question of what exactly we need to find. Indeed, a civilization similar to Earth’s modern one is not easy to see from a distance measured in thousands of light years. However, civilizations much older than us can change the world around us so significantly that we definitely need to see it.
Of course, when we know what to look for. This is the problem that experts from the Blue Marble Space Institute of Science (BMSIS) and NASA’s Goddard Space Flight Center addressed in a paper recently published in the journal Technological Forecasting and Social Change.
The starting point for their research was the opinion of famous scientist Freeman Dyson. He is known primarily as the author of the concept of a sphere around a star. However, he also made a more general point about the idea currently called the search for technosignatures.
Dyson said that any dream we had, unless it contradicted physics, would sooner or later be realized. And for alien civilizations that are thousands of millions of years older than ours, all of this should already be a reality. Therefore, the search for alien technosignatures is first and foremost about having a clear idea of what we can expect from our own future.
Technosphere
According to the above concept, each civilization creates around itself a “technosphere” — an area modified by technology, where there are things that don’t exist in nature. It may seem strange, but a civilization can cause them to appear in a very small amount of time by the standards of the Universe.
For example, between 1800 and 2024, the human population increased from 1 billion to 8.1 billion, an 800% increase. But this figure is not so impressive when you look at energy consumption. In the same time period, it increased from 5,653 to 182,230 TW, i.e. by 3,200%. This suggests that the future growth of humanity’s capabilities will be exponential, and soon we will possess powers never dreamed of before.
However, to do so, we need to understand what our dreams may or may not come true. It is impossible to accurately predict the future. But nevertheless, researchers have tried to understand what options for large-scale projects in principle can give us an alien civilization, which is older than ours by thousands of years.
What future is possible?
The first thing done by the researchers was to identify a huge number of scenarios that could happen at all in the future — 5,800. Then they filtered out those that contradicted the laws of physics. A large language model worked with the remaining ones, which reduced their number to 10.
Then, the scientists modeled the growth of humanity’s needs for each of the 10 scenarios and looked at what the world around them should look like in these cases. Accordingly, they realized what technologies could leave traces that we could see even at cosmic distances.
The most interesting conclusion was that exponential growth of civilization’s energy capabilities to infinity was observed in only one scenario out of ten. In all others it was either reaching a plateau or fading away. This means that the focus on the search for megastructures and other amazing manifestations of unlimited power is mistaken.
Most alien civilizations should be more stealthy and smeared energetically between stars and planets. In addition, it turned out that the state of the planet’s atmosphere is a bad enough indicator of an advanced civilization, since only the level of nitrogen dioxide is a sign of it.
According to phys.org
