Astronomers have made a groundbreaking discovery that reveals the hidden skeleton of the universe – the cosmic web. A team led by the University of Milano-Bicocca has observed a faint bridge of hydrogen stretching 3 million light-years between two ancient quasars, pulling the web’s finest filaments out of theory and into view.
The observation was made using the Multi-Unit Spectroscopic Explorer instrument on the European Southern Observatory’s Very Large Telescope in Chile. The team caught the slender strand linking the galaxies and traced it across its length, relying on MUSE to separate the filament’s weak hydrogen emission from background noise.
The discovery confirms a key prediction of cold dark matter theories: galaxies grow by siphoning gas along web-like funnels rather than gulping down isolated clouds. Seeing this flow directly provides scientists with a new handle on the unseen mass that makes up 85% of the universe, as its brightness depends on the density of surrounding dark matter.
The filament’s existence was previously thought to be beyond reach for telescopes, but patient observation and advanced instruments have made it possible to capture fine details. The match between simulated and observed filaments offers a reality check for alternative models of dark matter behavior, while also revealing how gas flows along these cosmic threads and shapes galaxy evolution.
The study’s findings suggest that inflow happens early and on grand scales, delivering fresh hydrogen to galaxies’ disks, fueling spiral arms, bursts of radiation, and chemical enrichment. Without this steady inflow, galaxies would exhaust their gas in a few hundred million years, fading away.
Future studies will benefit from next-generation instruments like the Extremely Large Telescope’s planned high-resolution spectrographs. Wider surveys will look for more filaments, sketching a full-scale map of the universe’s scaffolding and tightening constraints on dark matter physics and galaxy evolution.
Source: https://www.earth.com/news/first-direct-image-cosmic-web-filaments-hidden-highways-universe-framework