Study shows how civilizations could ‘spread’ across the Universe

The question of whether we are alone in space has been addressed in a sophisticated way by a research team from the University of the Philippines Los Banos. Assuming that the universe, although 14 billion years old, is still relatively young for the spread of life to habitable planets. study tested civilization models in a homogeneous environment.

To understand the potential for colonization of a possible advanced civilization through a network of so-called habitable planets in our universe, this study, which has not yet been peer-reviewed, evaluated several questions from the perspective of computational physics, “inspired by Percolation Theory.” In this model, civilizations can spread from planet to planet, or even among stars, until they reach a saturation point.

The paper, titled “The Percolation of ‘Civilization’ in a Homogeneous Isotropic Universe,” currently hosted in the arXiv preprint repository, is the so-called “Logistic growth model (LGF)”. The tool mathematically describes the growth of a population or system, taking into account constraints in the environment; that is, it increases rapidly initially but plateaus once an environmental limit is reached.

Some questions about colonization of the universe

To test their hypothesis, the authors used principles of computational physics in a hypothetical spherical portion of the Universe bounded by the Hubble horizon, that is, everything observable from Earth. Events or objects beyond this distance cannot be observed because they move away at a speed greater than the speed of light.

Therefore, after defining this finite and spherical region of cosmic space located within the radius of the Hubble horizon, the first question proposed in the study was: “How long would it take for an advanced civilization to colonize all habitable or habitable planets?” In a universe that can be physically observed by us?

Researchers then asked the question: “Could an advanced civilization colonize all habitable or habitable planets in a given global segment of the Universe?” Finally, in the context of colonization dynamics, “how does the number of occupied planets behave over time?”

Testing civilizations in three types of universes

The overall goal of the study was to answer three proposed questions but test a simplified system, “paving the way for more in-depth and complex research in the future,” according to the study. The proposed parameter was therefore a homogeneous and isotropic model, i.e. a universe consisting only of cells representing habitable planets.

From here, the researchers cut a three-dimensional spherical section and placed a “civilization” in the central cell. They found that in a static universe scenario, settlements behave exactly like the LGF, that is, a general pattern of relatively slow onset, limited by the scarcity of resources (in this case, only the number of habitable planets), because that kind of universe exists. It neither expands nor contracts.

In the case of a universe dominated by dark energy with a low Hubble parameter, Not all planets can be “colonised” as some travel beyond the speed of light. In the scenario of a matter-driven universe, the Hubble sphere shrinks (because the gravitational force between particles slows down the expansion of the universe). This leads to a limited colonization time, which depends on this variable.

Saying hello to extraterrestrial civilizations

In answer to physicist Enrico Fermi’s fundamental question: “Where are they all?” The team concluded that it is possible that our galaxy is currently in what they call Phase I, or slow colonization rate. Only a few intelligent and advanced civilizations here have decided to attempt interstellar colonization.

This slower phase may be further accentuated by the large distances between “living” planets, according to the study’s first author, Allan L. Alinea. However, once a certain number of civilizations are reached, we will enter Phase II with the expectation of rapid colonization. “If we have enough time to enter this phase, we may finally be able to say hello to aliens in the future.”

The study concludes that although there is a limited Hubble horizon in a universe governed by matter, it does not shrink, but grows, as in a dark energy universe. Because its growth is faster than population, “the colonization of all planets in a global portion of this universe always seems possible.”

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