Euclid's full sky map catalogs 1.2 billion galaxies

The European Space Agency released the complete sky survey from its Euclid telescope on Wednesday, a catalog of 1.2 billion galaxies that triples the size of any previous survey and maps the distribution of dark matter across a third of the sky.

Early analysis of the full dataset sharpens a tension that partial releases had hinted at: matter appears slightly less clustered at large scales than the standard cosmological model predicts. Two independent teams confirmed the signal at higher confidence than before.

"Either there is a systematic error we have all missed, or the model needs a new ingredient," the survey's lead scientist said. Follow-up spectroscopy campaigns begin this winter.