Key Takeaways:

  • Scientists estimate there are at least 36 intelligent civilizations in our galaxy.
  • This is based on a new theory that considers factors like star formation and habitable zones.
  • The theory makes assumptions about how long life takes to form and how long civilizations last.
  • Even if there are 36 civilizations, they are likely too far away to communicate with.
  • Searching for alien life can give us clues about how long our own civilization will last.

Is there anyone out there? This is the oldest and most important cosmic question of them all.

The Drake Equation has been our only resource for understanding the question for years, but it offers no indication of a solution. Researchers at the University of Nottingham believe they have developed a new computation, or rather, an estimate, based on the theory of “cosmic evolution” that indicates there are probably at least 36 existing intelligent civilizations in our Milky Way galaxy.

There are between 100 billion and 400 billion stars in the Milky Way, the galaxy that contains our solar system, and approximately one exoplanet for every star.

The new paper, which looks at the likely number of Communicating Extra-Terrestrial Intelligent (CETI) civilizations in the Milky Way, was published in The Astrophysical Journal. It is assumed that intelligent life forms on other planets in a similar manner to how it does on Earth.

Actually, a lot of assumptions are made by it. Indeed, way too many assumptions for some that doubt its generous conclusions.

One important supposition is that intelligent life is likely present on other planets, but it takes about five billion years for it to form—the same amount of time that Earth takes. Indeed, that is a significant assumption. Another is that a technological civilization, like ours has done so far, will endure for at least a century. After all, it took 4.5 billion years for Earth to evolve into a technological civilization with the ability to communicate.

How long civilizations continue to actively send out signals of their existence into space, such as TV and radio broadcasts from satellites, will determine how many civilizations there are.

The researchers have named this calculation the “Astrobiological Copernican Limit,” which suggests that there may be 36 living, sentient intelligent civilizations in our own galaxy on Earth-like planets circling Sun-like stars that are at least 4.5 billion years old. It considers:

  • histories of star formation.
  • how common stars with a lot of metal are (like the Sun).
  • the possibility that planets similar to Earth could be found in the habitable zones of stars.

“The classic method for estimating the number of intelligent civilizations relies on making guesses of values relating to life, but opinions about such matters vary quite substantially,” said Tom Westby, Assistant Professor, Faculty of Engineering at the University of Nottingham, and lead author on the paper. “Our new study simplifies these assumptions using new data, giving us a solid estimate of the number of civilizations in our galaxy.”

Based on a very optimistic view of how, where, and why life originates, the estimation of at least 36 civilizations has a large errorbar. There might be a tonne of extraterrestrial civilizations out there. It’s also possible that there are none.

Nevertheless, the authors point out that it is currently impossible to detect or communicate with any of these 36 civilizations because of their average distance of roughly 17,000 light-years.

The difficult subject of how long intelligent civilizations typically last also exists.

Professor of Astrophysics at the University of Nottingham Christopher Conselice led the research. “Searches for extraterrestrial intelligent civilizations not only reveals the existence of how life itself forms, but also gives us clues about how long our own civilization will last.” “This would show that our civilization could exist for much longer than a few hundred years if we find that intelligent life is common.”

Alternatively, it is ominous for our own long-term existence if we discover that our galaxy contains no thriving civilizations.

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