Astronomers Found a Structure So Big It Broke the Universe’s Rules… It Looks Like a Jellyfish

The structure you’re referring to, which is exceptionally large and has been said to challenge cosmological rules, is likely the Quipu Super structure.

Quipu is an extremely large, filamentary structure of galaxy clusters and superclusters, named after the ancient Inca knotted-cord recording system due to its long, knotted appearance.

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 Key Characteristics of Quipu

• Size: It spans over 1.3 billion light-years (more than 400 megaparsecs) in length, making it one of the largest structures ever discovered in the observable Universe.
• Mass: It is estimated to contain a staggering mass of around 200 quadrillion solar masses.
• Composition: It is a superstructure—an immense grouping of galaxy clusters and superclusters, making up a large portion of the observed matter in that region of space.

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 Why it “Breaks the Rules”

The discovery of structures like Quipu challenges the standard model of Big Bang cosmology, known as the Lambda Cold Dark Matter (CDM) model, and particularly the Cosmological Principle.

• Cosmological Principle: This principle asserts that, on sufficiently large scales, the Universe is homogeneous (the same everywhere) and isotropic (looks the same in all directions). Our current models predict a theoretical maximum size for structures before the Universe should appear smoothly distributed.
• Challenge to CDM: Structures over a certain size (often cited around billion light-years) are not expected to have had enough time to form and clump together since the Big Bang, according to the standard gravitational processes outlined in CDM. The existence of Quipu, and other structures of similar or even slightly larger scale like the Giant Arc or the Big Ring, suggests that our current models may be incomplete or that key assumptions need to be re-examined.

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“Jellyfish” Appearance

While the Quipu superstructure is a filamentary structure, the “jellyfish” description might be a more poetic or visual association due to its long, wispy appearance.

It’s also important to note that astronomers frequently observe an entirely different class of objects called Jellyfish Galaxies (such as NGC 4858 or ESO 137-001). These are individual galaxies moving at high speed through a galaxy cluster, where the intense pressure from the hot intergalactic gas (called ram-pressure stripping) strips away the galaxy’s gas, creating long, trailing “tentacles” of star-forming material that strongly resemble a jellyfish. These are much smaller than Quipu, but the name is quite common in astronomy.

Understanding the Cosmological Principle helps explain why a structure like Quipu is so surprising, and learning about ram-pressure stripping clarifies how a regular galaxy can get its “jellyfish” appearance.

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The Cosmological Principle: The Universe’s Fundamental Assumption

The Cosmological Principle is a fundamental assumption that underlies the standard Big Bang model (CDM). It states that the Universe, when viewed on a sufficiently large scale, is both homogeneous and isotropic.

1. Homogeneity (The Same Everywhere)

• Definition: The distribution of matter is uniform; there are no special locations. If you took a large, representative sample of the Universe from any location, the average density of galaxies and matter would be the same.
• Analogy: It’s like a cake where the batter (matter) is mixed perfectly. Any large slice will have the same amount of raisins (galaxies). You can’t find a center or an edge.

2. Isotropy (The Same in Every Direction)

• Definition: The Universe looks the same in every direction from any given observation point.
• Evidence: The Cosmic Microwave Background (CMB) radiation is the most compelling evidence. It is almost perfectly smooth (isotropic) across the entire sky.

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The Conflict with Quipu

The current CDM model, built on this principle, predicts a maximum size for gravitationally bound structures (like galaxy clusters and superclusters) that could have formed since the Big Bang.

• Quipu’s Size: Quipu is estimated to be over 1.3 billion light-years long.
• Theoretical Limit: The theoretical maximum size, based on the time since the Big Bang for matter to collapse into a single structure, is often cited around 1.2 billion light-years.
• The Challenge: The existence of structures like Quipu that exceed this expected limit suggests that the Universe may be less homogeneous on these very large scales than the Cosmological Principle assumes. This forces astronomers to consider either that:
  1. The Universe is not perfectly homogeneous on this scale.
  2. Our model for the growth of structure is incomplete (e.g., perhaps the processes of structure formation happened faster than currently calculated).

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 Ram-Pressure Stripping: Making a Jellyfish Galaxy

Ram-pressure stripping is a process that gives certain galaxies their distinctive “jellyfish” look. It occurs when a gas-rich galaxy (usually a spiral galaxy) moves at high speed through the hot, dense gas found in the center of a galaxy cluster.

1. The Ingredients

• The Galaxy: A galaxy containing a disc of relatively cool, star-forming gas.
• The Cluster: A large galaxy cluster, which is permeated by an extremely hot, diffuse gas called the Intracluster Medium (ICM).
• High Speed: The galaxy is falling into the cluster at a velocity of hundreds to thousands of kilometers per second.

2. The Mechanism

Ram pressure is essentially a form of dynamic pressure—the force exerted on an object moving through a fluid. The formula for this pressure, , is:

where:

• is the density of the Intracluster Medium (the “fluid”).
• is the velocity of the galaxy relative to the ICM.

This ram pressure acts like a powerful cosmic headwind that pushes on the galaxy’s gas disk.

3. The Stripping (Tails Form)

• The pressure from the ICM wind is stronger on the low-density gas in the outer parts of the galaxy than the galaxy’s own gravity is.
• The gas is stripped away from the galaxy’s disc, creating long, bright, trailing filaments—the “tentacles”—that look like a jellyfish’s body and streamers.
• The stripped gas often still has enough density to form new stars within the tails, which is why these tentacles are clearly visible in optical light.
• Effect: This process depletes the galaxy’s gas reservoir, eventually quenching (stopping) star formation, which is why galaxy clusters are filled with “dead,” gas-poor galaxies.

Conclusion: The Universe at Odds

The study of both the exceptionally large and the relatively smaller phenomena in the Universe—from the Quipu Superstructure to Jellyfish Galaxies—highlights a central tension in modern astronomy: the challenge of fitting all observations into our standard cosmological models.

• Challenging CDM: Structures like Quipu, spanning vast distances of over billion light-years, force us to question the strict validity of the Cosmological Principle on the very largest scales. Their existence suggests that the Universe might be lumpier and less homogeneous than predicted, potentially requiring a modification of the current Lambda Cold Dark Matter (CDM) model of cosmic evolution.
• Ram-Pressure as Local Physics: Conversely, the formation of Jellyfish Galaxies through ram-pressure stripping is a beautiful example of local physics dominating in high-density environments. This phenomenon demonstrates how the interaction of gas, gravity, and velocity within a galaxy cluster can dramatically change a galaxy’s fate, robbing it of its gas and effectively ending its star-forming life.

Ultimately, these discoveries show that while our current models provide a robust framework, the Universe continues to surprise us, revealing immense structures that defy theoretical size limits and dramatic physical processes that shape galactic evolution on a grand scale.