"Early Universe's Titanic Galaxy Cluster Collision Shakes Up Cosmology"

A collision between two massive galaxy clusters in the early universe challenges the standard theory of cosmology, according to a study published in The Astrophysical Journal. The collision, known as El Gordo, occurred at a high speed when the universe was only half its current age, contradicting the Lambda-cold dark matter (ΛCDM) standard model, which suggests that galaxies form first and then combine into larger clusters over time. The study's findings, based on detailed simulations and precise mass measurements, indicate that El Gordo's collision velocity is highly significant and cannot be explained within the framework of ΛCDM. This collision adds to the growing body of evidence that structure formation in the universe may have occurred faster than expected.