space Paradigm Challenge

We found a galaxy from 8 billion years ago that looks just like ours, which totally ruins our theory on how galaxies were built back then.

April 3, 2026

Original Paper

Milky-Way-like stars in a galaxy core 8 billion years ago revealed by gravitational lensing

Quirino D'Amato, Filippo Mannucci, Alessandro Sonnenfeld, Martina Scialpi, James W. Nightingale, Cristiana Spingola, Stefano Zibetti, Alessandro Marconi, Piero Rosati, Cosimo Marconcini, Guido Agapito, Anna Gallazzi, Enrico Di Teodoro, Gloria Andreuzzi, Francesco Belfiore, Elena Bertola, Caterina Bracci, Stefano Carniani, Elisa Cataldi, Avinanda Chakraborty, Matteo Ceci, Claudia Cicone, Anna Ciurlo, Giovanni Cresci, Alessandra De Rosa, Elisa Di Carlo, Anna Feltre, Michele Ginolfi, Isabella Lamperti, Bianca Moreschini, Emanuele Nardini, Michele Perna, Elisa Portaluri, Khatun Rubinur, Paolo Saracco, Paola Severgnini, Vincenzo Testa, Giulia Tozzi, Giacomo Venturi, Lorenzo Ulivi, Cristian Vignali, Maria Vittoria Zanchettin, Antonio Pepe

arXiv · 2604.01828

The Takeaway

Astronomers thought massive, old galaxies were mostly packed with tiny 'dwarf' stars. By using a cosmic magnifying glass, they found a distant galaxy with a mix of stars just like ours, suggesting galaxies haven't changed as much as we thought over billions of years.

From the abstract

The assembly of stellar-dominated cores in elliptical galaxies is key to understanding how cosmic structures evolved. Gravitational lensing offers unique insights into the nature of their stars. We report the discovery of the smallest known quadruply lensed quasar (radius ~0.2"), whose lensing galaxy at redshift 1.055 (5.5 billion years after the Big Bang) features a lensing mass of only ~2x10^10 M_sun. A Bayesian analysis, based on the system's exceptional properties and standard scaling relati