The superstructure "Quipu," recently identified, spans 1.3 billion light-years, challenging our understanding of the distribution of matter in space. This discovery, resulting from a study published in
ArXiv, opens new perspectives on the large-scale organization of the cosmos.
Distribution of CLASSIX clusters in the redshift slice z = 0.03 - 0.06 (filled and open circles). Clusters belonging to the five superstructures are colored: Quipu (red), Shapley (blue), Serpens-Corona Borealis (green), Hercules (purple), and Sculptor-Pegasus (beige).
Credit: Astronomy & Astrophysics.
© Bohringer et al. 2025.
Located between 424 and 815 million light-years from Earth, Quipu is composed of thousands of galaxies bound by gravity. With a mass equivalent to 200 million billion suns, it represents one of the largest structures ever observed. Its name, inspired by Inca quipus, evokes its complex filamentary shape, resembling a network of knots and cords.
Quipu: a unique cosmic architecture
The superstructure is distinguished by a main filament surrounded by secondary branches, forming a dense and interconnected ensemble. This configuration, revealed by X-ray observations, shows a cloud of overheated gas emitting characteristic radiation. These signals allow scientists to map the distribution of matter in this region of the Universe.
Quipu significantly influences its environment. Its mass distorts the light of distant objects, a phenomenon called gravitational lensing. This distortion affects measurements of the Hubble constant, essential for understanding the expansion of the Universe. Moreover, it alters the radiation of the cosmic microwave background, a relic of the Big Bang.
A discovery linked to cosmological models
The existence of Quipu confirms the predictions of the ΛCDM model, which describes the evolution of the Universe since the Big Bang. Numerical simulations had anticipated the formation of such structures, but their direct observation remains rare. Quipu and its neighbors represent about 45% of known galaxy clusters, offering valuable insight into the distribution of dark matter and dark energy.
Despite its immensity, Quipu is not an eternal entity. The accelerated expansion of the Universe will eventually fragment this superstructure into smaller units. This evolution recalls the dynamic and ever-changing nature of the cosmos, where even the largest structures are subject to colossal forces.
To go further: What is gravitational lensing?
Gravitational lensing is an effect predicted by Einstein's general relativity. It occurs when the light from a distant object is deflected by the gravity of a massive object, such as a galaxy cluster. Like an optical lens, this phenomenon allows the observation of otherwise invisible objects and the measurement of dark matter distribution.
What is the cosmic microwave background?
The cosmic microwave background is electromagnetic radiation emitted about 380,000 years after the Big Bang. It constitutes a "photo" of the young Universe and provides information about its evolution.
What is the Hubble constant?
The Hubble constant measures the expansion rate of the Universe. It is determined by observing the distance and recession velocity of galaxies. However, massive structures like Quipu can distort these measurements by adding local velocities to the global expansion.
Article author: Cédric DEPOND