At 1.4 billion light-years long, this is officially the biggest thing in our Universe

Quipu, the Universe's largest known superstructure, reshapes cosmology through immense interconnected galaxy clusters and dark matter.

Scientists have reported the discovery of the largest reliably measured superstructure—an enormous arrangement of galaxies, galaxy clusters, and dark matter linked together by gravity—in the universe. The formation, named “Quipu,” stretches about 1.4 billion light-years, a unit measuring how far light travels in one year through space, and is made mostly of dark matter, the invisible substance scientists detect only through its gravitational effects on galaxies and cosmic structures. It was identified while mapping galaxy clusters, huge collections of galaxies bound together by gravity, detected by the ROSAT X-ray satellite. The work was led by researchers at the Max Planck Institute for Extraterrestrial Physics and the Max Planck Institute for Physics, together with colleagues in Spain and South Africa.

Hans Böhringer, the project leader, explained: “If you look at the distribution of the galaxy clusters in the sky in a spherical shell with a distance of 416 to 826 million light-years, you immediately notice a huge structure that stretches from high northern latitudes to almost the southern end of the sky.” Quipu consists of 68 galaxy clusters, with a total mass of about 2.4×{(10)^7} solar masses, a standard astronomical unit equal to the mass of the Sun. Its size surpasses the Sloan Great Wall, which measures around 1.1 billion light-years.

The ROSAT satellite, launched in 1990, was key to this discovery. ROSAT was the first mission to map the entire sky in X-rays, a high-energy form of electromagnetic radiation emitted by extremely hot cosmic environments such as galaxy clusters. It created a catalogue of galaxy clusters by detecting the hot gas between galaxies that shines brightly in X-ray wavelengths. Joachim Trümper, the ROSAT project leader, recalled: “The catalogue was created with the help of the ROSAT X-ray satellite, built by Max Planck Institute for Extraterrestrial Physics. In 1990, the satellite mapped the entire sky using a high-resolution X-ray telescope for the first time.” Over the years, researchers refined the data, measuring distances and building a three-dimensional map of matter distribution. This map revealed Quipu as the largest known structure within a billion light-years of Earth.

The research paper adds important context. It explains that to measure cosmological parameters—the numerical values describing the universe’s expansion, matter density, geometry, and evolution—precisely, scientists must account for how local large-scale structures affect observations. These effects include changes in the cosmic microwave background (CMB), the faint leftover radiation from the early universe shortly after the Big Bang, distortions caused by gravitational lensing, where massive objects bend light by warping spacetime, and the impact of streaming motions on the Hubble constant, the value that measures how fast the universe is expanding. Streaming motions, for example, come from mass concentrations up to 250 megaparsecs away; a megaparsec equals one million parsecs, or about 3.26 million light-years.

The team carried out the first all-sky assessment of the largest structures at distances between 130 and 250 megaparsecs. Among the five most prominent, Quipu was the largest, with a length of more than 400 megaparsecs and a mass of about 2 × 1017 solar masses. These superstructures are not rare features.

They contain about 45% of galaxy clusters, 30% of galaxies, 25% of matter, and occupy 13% of cosmic volume. This means they form a major part of the universe. The researchers also found that galaxy density is higher around superstructures compared to isolated clusters. Simulations based on the Lambda-CDM cosmology model—the standard model of cosmology in which “Lambda” represents dark energy and “CDM” stands for cold dark matter—show similar structures, supporting the reliability of the findings.

The team noted that superstructures should leave a mark on the cosmic microwave background through what is called the integrated Sachs-Wolfe effect, a subtle change in CMB radiation caused when light passes through evolving gravitational fields created by massive cosmic structures. They searched for this in Planck satellite data and found a signal of the expected strength, though with low statistical significance, meaning the evidence is suggestive but not yet strong enough to rule out the possibility of chance fluctuations. Gayoung Chon emphasized: “Even if these are only corrections of a few percent, they become increasingly important as the accuracy of cosmological observations increases.”

Quipu was named after the knotted string system used by the Incas for record-keeping. The structure resembles a long fibre with side strands, much like the ancient script. The name also reflects the role of the European Southern Observatory in Chile, where many distance measurements were made. Quipus are displayed in Museo Chileno de Arte Precolombino, linking this cosmic discovery to human history.

This finding is important not only for mapping the universe but also for testing cosmological models and studying how galaxies evolve in different environments. It shows that the largest structures in the universe can influence even the most precise measurements scientists make today.

Source: Max Planck Institute, ArXiv

This article was generated with some help from AI and reviewed by an editor. Under Section 107 of the Copyright Act 1976, this material is used for the purpose of news reporting. Fair use is a use permitted by copyright statute that might otherwise be infringing.

Source

Hope you enjoyed this news post. Feedback welcome.

Posted Monday 18 May 2026 at 7:35 am AEST (my time).

News posts: 2023 5,800+ | 2024 5,700+ | 2025 5,700+ | 2026 (to end of April) 1,700

RIP Matrix