Astronomers spot 4-million-light-year cosmic filament in Ursa Major

Astronomers spot a cosmic filament in Ursa Major

Astronomers have directly observed a thin, nearly straight filament of galaxies stretching across the Ursa Major constellation. The discovery, detailed in a preprint paper on arXiv, provides rare observational evidence for the delicate threads of the cosmic web, the universe's large-scale structure.

The filament spans nearly four million light-years. It is dominated by dark matter, which acts as a gravitational scaffold guiding the formation and evolution of galaxies along its length.

The cosmic web's hidden scaffolding

The universe is structured like a vast web, with galaxy clusters at dense knots connected by long filaments and separated by enormous voids. This architecture is shaped primarily by the gravity of dark matter, which does not emit light but exerts a powerful gravitational pull.

These filaments are theorized to be cosmic highways. They funnel gas into regions where it can coalesce, feeding the birth of new stars and galaxies.

Key components of the cosmic web include:

• Dense galaxy clusters at the intersections
• Long, thin filaments of dark matter and gas
• Vast, empty voids between the structures

China's FAST telescope makes the detection

The discovery was made using China's Five-hundred-meter Aperture Spherical radio Telescope (FAST). Its extreme sensitivity allowed it to detect the faint, diffuse signal from the linear arrangement of galaxies.

The team used FAST's HI observations to identify a coherent structure of galaxies distributed from northeast to southwest. This pinpointed a specific, delicate filament that had previously been theoretical or too faint to see clearly.

A cosmic nursery for galaxy formation

The identification of this filament has significant implications for understanding how galaxies form and evolve. It acts as a direct pipeline, with dark matter's gravity drawing in the raw materials for star formation.

This shows that even these subtle, thin strands in the cosmic web play a crucial role. They are not just connectors but active sites of cosmic development, influencing the destiny of galaxies over billions of years.

The finding offers tangible proof of the universe's large-scale design. It demonstrates how new instruments like FAST are moving cosmology from theory into direct observation of the universe's fundamental architecture.