Giant Stellar Walls: Galaxy Superclusters Explained Quiz

Galaxy superclusters are among the largest known structures in the cosmos. They consist of smaller galaxy groups and clusters that are interconnected by thin strands of matter. These massive collections are held together by gravity and define the boundaries of the cosmic web. Understanding these formations helps scientists map the distribution of matter across billions of light-years.

True. The Milky Way resides within the Laniakea Supercluster, which translates to "immense heaven" in Hawaiian. This massive structure contains approximately 100,000 galaxies stretching across 520 million light-years. Mapping the boundaries of Laniakea has allowed astronomers to better understand the gravitational flow and movement of our local galactic neighborhood within the cosmic web.

Galaxy walls, or cosmic walls, are the largest individual components of the universe's architecture. They represent vast sheets of galaxies and superclusters that form the "walls" surrounding nearly empty voids. These structures, such as the Sloan Great Wall, provide evidence for how matter clumped together following the initial expansion of the universe.

Superclusters are defined by the gravitational pull that galaxies exert on one another and the underlying distribution of dark matter. While gravity tries to pull these structures together, the overall expansion of the universe works to push them apart. Planetary rotation is a localized force and does not influence the formation of these massive intergalactic structures.

Dark matter is invisible but exerts a significant gravitational force. It acts as the primary building material or "scaffold" that attracts hydrogen gas and galaxies into specific patterns. Without the gravitational influence of dark matter, the massive cosmic walls and superclusters we observe today would not have had enough mass to form during the history of the universe.

False. While gravity holds the internal components of a supercluster together, these structures are so large that the expansion of the universe often overcomes their internal gravity. Most superclusters are actually moving away from each other as space expands. This helps researchers calculate the Hubble constant and understand the accelerating rate of the universe's growth.

The Great Attractor is a gravitational anomaly located within intergalactic space at the center of the Laniakea Supercluster. It possesses a mass so immense that it influences the motion of galaxies across hundreds of millions of light-years. By observing how galaxies "drift" toward this region, astronomers can map the hidden mass distribution of the surrounding cosmic environment.

The Great Wall and the Perseus-Pisces Supercluster are iconic examples of the massive sheets and chains of galaxies that define the cosmic web. Laniakea is our own home supercluster. In contrast, the Kuiper Belt is a small region within our solar system consisting of icy objects, which is insignificantly small compared to the scale of intergalactic superclusters.

Instead of just looking at positions, scientists use "velocity fields" to see which way galaxies are moving. If a group of galaxies is all moving toward the same central region, they are considered part of the same supercluster. This movement-based mapping provides a more accurate picture of the gravitational boundaries than simple visual observation alone.

True. The universe resembles a honeycomb or soapy foam. The "bubbles" are the cosmic voids, which contain very few galaxies, while the "film" of the bubbles consists of the galaxy walls and superclusters. These voids grow over time as gravity pulls matter away from them and into the dense walls, contributing to the universe's large-scale structure.

Gravitational instability refers to the process where slight irregularities in the density of the early universe were amplified. Over millions of years, the denser regions attracted more matter, eventually forming the walls and superclusters we observe today. This concept is fundamental to understanding how an almost uniform early universe evolved into a complex, web-like structure.

The Great Wall is a colossal sheet of galaxies that was one of the first major discoveries regarding the large-scale structure of the universe. It spans over 500 million light-years and is thousands of times larger than our own galaxy. Such structures are found in deep space and are not contained within any single galaxy like the Milky Way.

Density is the amount of matter in a given volume. Cosmic walls are high-density regions packed with galaxies, gas, and dark matter. As you move into a void, the density of matter drops to nearly zero. This extreme contrast in density is a fundamental feature of the cosmic web and illustrates how gravity unevenly distributes matter throughout the universe.

True. Shortly after the Big Bang, the universe was almost perfectly uniform, but tiny ripples in density existed. Over billions of years, gravity amplified these ripples, pulling more matter into the slightly denser areas. These areas eventually grew into the galaxies, clusters, and superclusters we see today, while the less dense areas became the vast cosmic voids.

Filaments are the "threads" of the cosmic web that link superclusters together. They are composed of dark matter and hot gas and serve as pathways along which galaxies migrate toward denser nodes. These filaments represent the primary transport system of matter in the universe and are essential for maintaining the integrity of the large-scale structure.

Superclusters contain visible matter like stars and planets within galaxies, as well as vast amounts of hot intergalactic gas. However, the majority of their mass comes from invisible dark matter. While dark energy exists throughout space and affects the expansion of the supercluster, it is considered a property of space itself rather than a form of matter contained within the structure.

The "Zone of Avoidance" is an area of the sky where the dust and stars of our own Milky Way galaxy block our view of the distant universe. Because we are inside the structure we are trying to map, we have to use infrared and radio telescopes to peer through the galactic fog and identify the galaxies that belong to Laniakea.

False. While gravity is the dominant force that clumps matter into walls and superclusters, the initial conditions of the Big Bang and the current pressure of dark energy also play vital roles. Dark energy acts as an opposing force to gravity, stretching the structures and influencing how quickly they move apart, which ultimately shapes the entire cosmic web.

The cosmic web is the name given to the interconnected network of filaments, walls, nodes, and voids. It represents the universe's large-scale structure on the grandest possible scale. This web-like pattern is a result of gravitational forces acting over 13.8 billion years, creating an organized architecture that astronomers study to understand the history of cosmic evolution.

Redshift occurs when the light from a galaxy is stretched toward longer wavelengths as it moves away from us. By measuring this shift, astronomers can calculate how far away a galaxy is and how fast it is receding. This data is essential for creating three-dimensional maps of superclusters and walls, allowing us to see the depth of the cosmic web.