When three large celestial bodies interact in space, their gravitational forces affect one another in ways that can appear random and unpredictable. This phenomenon is often described as chaotic. However, recent research suggests that instead of descending into chaos, these interactions can adhere to distinct patterns, often resulting in the quick expulsion of one object from the system. This groundbreaking discovery could significantly enhance our comprehension of gravitational waves and other cosmic phenomena.
When three large celestial bodies come together in the cosmos, the gravitational forces they exert on each other lead to unpredictable outcomes. Commonly, this is viewed as chaos. Yet, a researcher from the University of Copenhagen has found that these encounters frequently follow specific patterns instead, leading to the rapid expulsion of one of the objects. This revelation may be crucial for deepening our understanding of gravitational waves and various other universe-related concepts.
Currently, the most popular series on Netflix is the science fiction adaptation of 3-Body Problem. Based on a novel series by Liu Cixin, it showcases a diverse cast of characters, multiple eras, and even alien beings. The core theme revolves around a star system where three stars orbit each other.
This star system, involving three celestial bodies that exert gravitational influence on one another, has captured the attention of scientists since Isaac Newton, the father of gravity, first explained it. While the interaction between two bodies is predictable, adding a third turns the scenario into something not only complex but chaotic.
“The Three-Body Problem is one of the most renowned unsolvable dilemmas in mathematics and theoretical physics. The theory suggests that when three bodies come together, their interactions develop chaotically, without any regular patterns and completely independent of their initial conditions. However, our extensive simulations reveal that there are ‘islands of regularity’ amidst this chaos, which depend on the initial positioning of the three bodies along with their speeds and angles at which they approach each other,” states Alessandro Alberto Trani from the University of Copenhagen’s Niels Bohr Institute.
Trani expresses hope that this finding will enhance astrophysical models, considering that the Three-Body Problem poses not only a theoretical quandary but is also commonly found in cosmic events, making its exploration essential.
“To grasp the nature of gravitational waves that arise from black holes and other massive moving bodies, it is critical to study how black holes interact during encounters and mergers. The forces involved are monumental, especially when three black holes engage with each other. Thus, understanding these interactions could provide vital insights into gravitational waves, the nature of gravity, and many other fundamental enigmas of the universe,” notes the researcher.
A Tsunami of Simulations
To explore this phenomenon, Trani developed a software program called Tsunami, designed to model the movements of celestial entities based on established natural laws, including Newtonian gravity and Einstein’s theory of general relativity. He conducted millions of simulations of three-body interactions under specific defined parameters.
The simulations began with the locations of two objects in their shared orbit—essentially their position along a 360-degree axis. The approach angle for the third object varied by 90 degrees.
These countless simulations encompassed numerous combinations within this framework, creating a broad depiction of all possible outcomes, akin to a large tapestry woven from initial configurations. This is where observable ‘islands of regularity’ can be identified.
The colors in these results indicate which object gets expelled following the encounter, typically the one with the least mass.
“If the three-body problem were entirely chaotic, we’d only see a chaotic jumble of indistinguishable dots, with every outcome merging into one another without any order. Instead, we identify regular ‘islands’ that emerge from this chaotic backdrop, where the system acts predictably, leading to consistent outcomes—and thus consistent colors,” explains Trani.
Two Steps Forward, One Step Back
This discovery holds significant promise for grasping a phenomenon previously thought impossible to analyze. However, it also presents new challenges for scientists. While they are familiar with calculating pure chaos using statistical methods, the emergence of regularities amid chaos complicates their calculations.
“When certain areas on this outcome map suddenly indicate regular patterns, it disrupts standard probability assessments, resulting in inaccurate forecasts. Our current goal is to learn to integrate statistical methods with numerical calculations, which provide high accuracy in contexts of regular behavior,” says Alessandro Alberto Trani.
“As a result, my findings have brought us back to the drawing board, but they also open the door to a whole new realm of understanding in the long run,” he adds.
* Extra info: 4-Body Problem
During the pandemic, Alessandro Alberto Trani began a side project focused on fractal universes within the context of the Three-Body Problem, which led him to contemplate gradually mapping outcomes in search of patterns.
While he was aware of the well-known problem from his studies, he had not explored the fictional works associated with it—like the recent Netflix adaptation or the underlying novel titled “The Three-Body Problem” by Liu Cixin. However, out of sheer curiosity, he familiarized himself with the story enough to deduce that it discusses a “4-Body Problem.”
“As I understand it, the narrative revolves around a star system consisting of three stars and one planet that is frequently drawn into chaotic situations. Such a setup is more accurately categorized as a Four-Body Problem. Nevertheless, according to my simulations, the planet would most likely be quickly obliterated by one of the three stars, subsequently reducing it back to a Three-Body Problem,” the researcher chuckles.
