A 1.3B-light-year-across ring of galaxies has confounded astronomers
Astronomers have identified a 1.3‑billion‑light‑year‑wide “Big Ring” of galaxies, near a previously found “Giant Arc,” at a distance of about 9.2 billion light‑years—structures so large they may challenge the standard ΛCDM model and the assumption that the universe is homogeneous on the largest scales. Commenters debate whether such a ring could arise from random clustering, gravitational effects, or unknown early‑universe physics, with some pointing to the reported ~5σ statistical significance as evidence it is unlikely to be mere chance. Others explore more speculative ideas, from exotic space‑time geometries to advanced civilizations, while emphasizing that improved data and analysis will be needed to confirm what these formations really imply about cosmology.
Statistical significance vs. coincidence
- Some argue a ring-like structure is expected occasionally from a random galaxy distribution; with enough “dots,” circles, rabbits, or “lol :)” patterns will appear.
- Others cite the paper’s analysis (CHMS algorithm, ~5.2σ departure from random) as evidence it is unlikely to be pure noise and therefore publishable.
- Skeptics reply that the artist’s impression is misleading; the actual structure is jagged and filament-like, and could be an instance of over‑interpretation or “constellation‑ism.”
3D geometry, projection, and our viewpoint
- Several discuss whether the “ring” might be a 2D projection artifact: galaxies at varied distances that only look circular from Earth’s line of sight.
- Counterpoints reference the use of redshift slices (Mg II absorbers at specific z) showing galaxies at similar distances, implying a genuine 3D overdensity.
- Another commenter claims the structure has large radial thickness (~400 Mpc), comparable to the largest known structures, and criticizes the work as effectively picking a circle from a thick shell.
Cosmological principle and large-scale structure
- A major thread connects this and similar discoveries (e.g., the Giant Arc) to possible violations of homogeneity and isotropy in ΛCDM.
- One side stresses that standard cosmology assumes large-scale homogeneity; structures this large are unexpected and may challenge the cosmological principle.
- Others say the principle has been fruitful (e.g., in predicting the CMB) and remains a necessary approximation; isolated anomalies do not yet overturn it.
Randomness, patterns, and probability arguments
- Long subthreads debate whether seeing a ring is “astonishing” or just inevitable pattern-finding in huge datasets.
- Analogies include dice and coin tosses, random strings vs. meaningful English sentences, and shapes emerging from random point clouds.
- Some emphasize multiple‑endpoints/data‑mining bias: from billions of galaxies, some subset will look special; others counter that certain configurations are vastly rarer and legitimately surprising.
Speculative ideas and alternative explanations
- Lighthearted or speculative suggestions include alien megastructures, Kardashev Type III+ civilizations, gravitational lensing artifacts, other universes “poking” into ours, or simulation glitches.
- A technical side thread explores whether such a structure could be related to rotating spacetime or closed timelike curves; consensus in the thread is that known GR mechanisms cannot plausibly do this at these scales.
Miscellaneous clarifications
- Commenters note the ring is ~9.2 billion light-years away; we see it as it was when the universe was young.
- The “Big Ring” and the “Giant Arc” are described as neighbors to each other in distance and sky position, not neighbors to Earth.