How long can an advanced civilization continue trying to contact us

Scientists have analyzed how long an extraterrestrial civilization will be able to maintain technosignatures — that is, purposefully created and side signals by which we can clearly determine its presence. It turns out that most of them will be short-term.

Technosignatures are an extremely short-lived thing. Source:

Technosignatures from extraterrestrial civilizations

Two scientists from the universities of Rome and Lausanne recently published an article in The Astronomical Journal on the question of how durable technosignatures can be. This question is very important for our understanding of how easy it really is to detect traces of an alien civilization and come into contact with it.

Technosignatures are any traces of alien technology that we can identify. Most often, these are various radiations that can be perceived by astronomical instruments on Earth. Traditionally, they are considered the most reliable way to establish the presence of an alien civilization.

At the same time, it is traditionally believed that technosignatures are extremely durable. This is based on the assumption that alien civilizations are much older than ours. This leads to a picture of the universe in which signals from other life forms have been floating through outer space for millions of years.

Technosignatures are short-lived

The main idea expressed by the authors of the new study is that technosignatures are short-lived. Even if the civilization that created them does not disappear in a few thousand years, it is not a fact that the radio signal will last at least tens of terrestrial years.

The researchers suggest that some technosignatures, such as thermal radiation from Dyson spheres, may indeed last millions of years. Therefore, they may eventually lead us to already dead civilizations. However, in most cases we will be dealing with recently sent signals that have come to us from a relatively short distance.

The authors of the study base this conclusion on the fact that the creation and maintenance of most technosignatures is a rather expensive thing, and civilization will do this as long as they are at least somewhat useful to them. And then they will be eliminated as unnecessary.

The conclusion of the work is based on a detailed statistical analysis. It, in turn, relies on the so-called Lindy’s Law, which states that the expected duration of technology use is proportional to its age. This means that the more primitive the technology, the more likely it is that aliens will use it over and over again for thousands of years.

However, Lindy’s Law is just an assumption, confirmed by only a few observations from the practice of using technology on Earth. Therefore, it is quite possible that it only adds confusion to the calculations.

According to

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