The Universe as a Distant Forest: Testing Homogeneity ✎ express

Original: "Measurements of the Angular Homogeneity Scale from DESI DR1"
arXiv:2606.07854 · 2026-06-05 · arXiv non-exclusive · independent analysis · 1 min
Astronomers have confirmed that on scales of tens of lunar disks, the Universe becomes perfectly smooth.

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The Universe resembles a dense forest: up close, individual galaxy-trees are visible, gathered into groves, but from a distance everything merges into a solid green canopy. The boundary beyond which the cosmos becomes homogeneous is called the angular scale of homogeneity: it's the size of a patch of sky from which galaxies are distributed evenly.

Astronomers analyzed data from the DESI project, which used spectroscopy (splitting light) to measure distances to hundreds of thousands of bright red galaxies. Scientists "sliced" space into layers corresponding to epochs 4–7 billion years ago, and looked only at angular coordinates, as if assessing the forest canopy from different hills.

It turned out that at angles greater than 70 degrees (tens of full Moons in a row), clumpiness disappears, and the Universe becomes statistically smooth. This result exactly matches the predictions of the standard cosmological model and earlier observations. Thus, the fundamental principle of homogeneity withstands the test of the latest data.

The path to this discovery began with the work of Georges Lemaître and Edwin Hubble, who laid the foundations of the expanding Universe theory.

Cosmic homogeneity is not just a philosophical principle: without it, we couldn't reliably measure distances in the Universe, and the Big Bang theory itself would lose its footing.

Scientists
Alan GuthAlexander FriedmannAndrei LindeGeorges LemaîtreJames PeeblesSubrahmanyan Chandrasekhar
Concepts
cosmological homogeneity cosmological data standard ruler cosmic distance ladder lambda cdm cosmic distance measurement standard candle cosmology sdss square degree age of the universe supernova cosmology hubble constant hubble constant measurement observable universe desi sigma 8 high redshift galaxies sky survey lcdm model