Free Astronomy Magazine July-August 2024

26 JULY-AUGUST 2024 ASTRO PUBLISHING by NOIRLab − Josie Fenske The most detailed view ever of the expanding Universe S ince beginning its survey of the sky in 2021 the Dark Energy Spectroscopic Instrument (DESI) has observed a new set of 5000 galaxies every 20 minutes, totalling more than 100,000 galaxies per night, in its quest to create the largest 3D map of the Universe ever. Using the survey’s first-year data, which contains the largest extra- galactic spectroscopic sample ever collected, astronomers report that they have measured the Universe’s expansion history over the last 11 billion years with a precision better than 1%. These measurements con- firm the basics of our best model of T he Dark Energy Spectroscopic Instrument (DESI) has made the largest 3D map of our Universe to date. This slice shows the galaxies mapped in the first year of DESI’s five-year survey. Earth is at the center of this thin slice of the full map. In the magnified section, it is easy to see the underlying structure of matter in our universe. [Claire Lamman/DESI collaboration; custom colormap package by cmastro]