There could be 12,500 civilizations in the Milky Way: we might be descendants of extraterrestrials from deep space.

Currently, scientists are receiving vast amounts of new information almost every day not only about our galaxy, the Milky Way, but also about the universe as a whole. However, the question remains open: are we alone in the universe? Is there life beyond Earth? Are there other intelligent species on different planets? Michael Reinsteiner from McMaster University, Canada, believes that, considering the available research data, it is quite likely that other technologically advanced species exist somewhere in the universe. The scientist discusses this in an article for The Conversation.

Definition of Life

The current main description of life is that it is a self-sustaining chemical system capable of processing information and maintaining a state of low entropy with minimal disorder or randomness.

Living organisms constantly require energy to maintain their molecular organization as well as their highly organized structures and functions. Without this energy, life would quickly descend into chaos and cease to exist.

This definition of life illustrates its complex nature, as well as its ability to adapt and evolve.

Life on Earth is based on the interactions of DNA, RNA, and proteins. DNA contains the genetic instructions necessary for the development, survival, and reproduction of an organism. These instructions are transformed into messages that direct the production of proteins, which are among the essential components of cells responsible for a wide range of functions.

The intricate system of DNA replication, protein synthesis, and cellular processes, all based on long chains of molecules connected by carbon atoms, is fundamental to life on Earth. However, there may be forms of life in the universe based on entirely different biochemistries.

Extraterrestrial Life May Not Be Carbon-Based

Extraterrestrial life could be based not on carbon, but on silicon, which shares chemical similarities with carbon. If such life forms exist, they would likely possess unique characteristics and adaptive capabilities.

Although there are no silicon-based living organisms on Earth, this element plays a crucial role in many known life forms on our planet. It is an important secondary component for many plants and animals, fulfilling essential roles. This demonstrates that silicon can serve as a building block for living organisms.

How Did Life Arise on Earth?

Regarding the origin of life on Earth, there are two main hypotheses:

• one suggests that the building blocks of life were delivered to our planet by meteorites and asteroids;
• the other posits that these building blocks formed spontaneously through geochemistry under the conditions present on early Earth.

There is already evidence that meteorites and asteroids carry organic molecules, including amino acids, which are necessary for life. It is possible that organic molecules formed in deep space and then arrived on Earth.

On the other hand, geochemical processes on early Earth, occurring in warm bodies of water, may have also provided the necessary conditions and ingredients for the emergence of life.

Many biological molecules are chiral, meaning they exist in two forms that are mirror images of each other. While both left-handed and right-handed molecules are typically produced in equal amounts, recent studies of meteorites have shown a slight asymmetry, with left-handed molecules being about 60% more prevalent.

This asymmetry in organic molecules of cosmic origin can also be found in the proteins, sugars, amino acids, RNA, and DNA of living organisms on Earth. Therefore, this fact may support the hypothesis of an extraterrestrial origin of life on Earth, suggesting that humans could be descendants of life that arose somewhere else in the cosmos.

Thousands of Intelligent Civilizations in the Milky Way

The Drake Equation provides a framework for estimating the number of possible extraterrestrial civilizations in the Milky Way. This equation includes factors such as the rate of star formation, the number of stars with planets, and the number of planets where intelligent life could potentially arise. According to the most optimistic estimate based on the Drake Equation, there could be 12,500 intelligent alien civilizations just in the Milky Way.

Given that the universe contains an incredibly vast number of stars and planets, the likelihood that we are alone in the universe seems extremely small. The probability that humanity is the only technologically advanced civilization in the observable universe is estimated to be 1 in 10 billion trillion. Furthermore, the likelihood of a developed civilization existing on any habitable planet is more than 1 in 60 billion.

It is estimated that there are around 200 billion trillion stars in the observable universe, many of which have planets that could support life. This means it is highly probable that somewhere in space, even within our galaxy, there are other technologically advanced civilizations.

Now, the only remaining task is to discover them. But perhaps these civilizations have already discovered us and simply choose not to communicate.