Free Astronomy Magazine November-December 2024

NOVEMBER-DECEMBER 2024 derstanding of galaxy formation, such early galaxies are expected to appear more chaotic. The rota- tion and structure of REBELS-25 were revealed using the Atacama Large Millimeter/submillimeter Ar- ray (ALMA), in which the European Southern Observatory (ESO) is a partner. The most distant rotating disc galaxy found by ESO − Bárbara Ferreira R esearchers have discovered the most distant Milky-Way- like galaxy yet observed. Dubbed REBELS-25, this disc galaxy seems as orderly as present-day galaxies, but we see it as it was when the Universe was only 700 million years old. This is surprising since, according to our current un- T his image shows the galaxy RE- BELS-25 as seen by the Atacama Large Millimeter/submillimeter Array (ALMA), overlaid on an infrared image of other stars and galaxies. The infrared image was taken by ESO’s Visible and Infrared Survey Tele- scope for Astronomy (VISTA). In a recent study, researchers found evi- dence that REBELS-25 is a strongly rotating disc galaxy existing only 700 million years after the Big Bang. This makes it the most distant and earli- est known Milky Way-like galaxy found to date. [ALMA (ESO/NAOJ/ NRAO)/L. Rowland et al./ESO/J. Dun- lop et al. Ack.: CASU, CALET]