Researchers have used simulations to research the cosmic internet, the filamentary sample of galaxies that exists on giant scales all through the universe. By treating the distribution of galaxies as a set of factors and making use of mathematical strategies developed for supplies science, they’ve quantified the relative dysfunction of the universe and gained a greater understanding of its elementary construction. Credit score: NASA/College of Chicago and Adler Planetarium and Astronomy Museum
The universe is peppered with galaxies, which, on giant scales, exhibit a filamentary sample, known as the cosmic internet. This heterogeneous distribution of cosmic materials is in some methods like blueberries in a muffin the place materials clusters in sure areas however could also be missing in others.
Primarily based on a sequence of simulations, researchers have begun to probe the heterogeneous construction of the universe by treating the distribution of galaxies as a set of factors—like the person particles of matter that make up a cloth—fairly than as a steady distribution. This method has enabled the applying of arithmetic developed for supplies science to quantify the relative dysfunction of the universe, enabling a greater understanding of its elementary construction.
Visualization of the biggest buildings within the universe from the Sloan Digital Sky Survey. Credit score: NASA/College of Chicago and Adler Planetarium and Astronomy Museum
“What we discovered was that the distribution of galaxies within the universe is kind of totally different from the bodily properties of typical supplies, having its personal distinctive signature,” defined Oliver Philcox, a co-author of the examine.
This work, now printed in Bodily Overview X, was performed by Salvatore Torquato, frequent Member and Customer on the Institute for Superior Research and Lewis Bernard Professor of Pure Sciences based mostly in Princeton University’s departments of chemistry and physics; and Oliver Philcox a visiting Ph.D. student at the Institute from September 2020 to August 2022, now a Junior Fellow in the Simons Society of Fellows, hosted at Columbia University.
This visualization presents a 3D view of the biggest buildings within the universe. It begins with knowledge from the Sloan Digital Sky Survey and zooms out to disclose knowledge from WMAP. Credit score: NASA/University of Chicago and Adler Planetarium and Astronomy Museum
The pair analyzed public simulation data generated by Princeton University and the Flatiron Institute. Each of the 1,000 simulations consists of a billion dark matter “particles,” whose clusters, formed by gravitational evolution, serve as a proxy for galaxies.
One of the main results of the paper concerns the correlations of pairs of galaxies that are topologically connected to one another by means of the pair-connectedness function. Based on this—and the array of other descriptors that arise in the theory of heterogeneous media—the research team showed that on the largest scales (on the order of several hundred megaparsecs), the universe approaches hyperuniformity, while on smaller scales (up to 10 megaparsecs) it becomes almost antihyperuniform and strongly inhomogeneous.
A section of the universe (black and white), with dark matter halos indicated by points and their associated large-scale topological structures indicated by colors. Credit: Philcox & Torquato; The Quijote Simulations
“The perceived shift between order and disorder depends largely on scale,” stated Torquato. “The pointillist technique of Georges Seurat in the painting A Sunday on La Grande Jatte (see image below) produces a similar visual effect; the work appears disordered when viewed up-close and highly ordered from afar. In terms of the universe, the degree of order and disorder is more subtle, as with a Rorschach inkblot test that can be interpreted in an infinite number of ways.”
“A Sunday on La Grande Jatte” by Georges Seurat.
Statistical tools, specifically nearest-neighbor distributions, clustering diagnostics, Poisson distributions, percolation thresholds, and the pair-connectedness function, allowed the researchers to develop a consistent and objective framework for measuring order. Therefore, their findings, while made in a cosmological context, translate to a number of other dynamical, physical systems.
This interdisciplinary work, combining the techniques of cosmology and condensed matter physics, has future implications for both fields. Beyond the distribution of galaxies, many other features of the universe can be explored with these tools, including cosmic voids and the ionized hydrogen bubbles that formed during the reionization phase of the universe. Conversely, the novel phenomena discovered about the universe may also provide insight into various material systems on Earth. The team recognizes that more work will be needed before these techniques can be applied to real data, but this work provides a strong proof-of-concept with significant potential.
Reference: “Disordered Heterogeneous Universe: Galaxy Distribution and Clustering across Length Scales” by Oliver H. E. Philcox and Salvatore Torquato, 14 March 2023, Physical Review X.
DOI: 10.1103/PhysRevX.13.011038