Scientists have uncovered one of the universe's most colossal spinning structures, a 50-million-light-year-long cosmic phenomenon that challenges our understanding of galactic evolution. This discovery reveals a fascinating pattern: galaxies within a vast dark matter filament are predominantly spinning in the same direction as the filament itself.
The filament, a thread in the cosmic web, is a colossal structure spanning the entire universe, primarily composed of dark matter with traces of ordinary matter. It's located a staggering 140 million light-years away and boasts a nested structure. At its core lies a row of 14 galaxies, almost perfectly aligned in a line 5.5 million light-years long and 117,000 light-years wide. These galaxies are rich in hydrogen gas, essential for star formation. This unique arrangement is then embedded within the larger filament, which stretches an astonishing 50 million light-years and hosts approximately 300 galaxies.
What makes this discovery truly remarkable is the combination of spin alignment and rotational motion. Lyla Jung, a researcher at the University of Oxford, draws an intriguing analogy: 'It's like a teacups ride at a theme park. Each galaxy spins like a teacup, but the entire platform, the cosmic filament, is also rotating. This dual motion provides us with a rare glimpse into how galaxies acquire their spin from the larger structures they inhabit.'
Jung and Madalina Tudorache, both from Oxford, led the study using the MeerKAT radio telescope in South Africa. They tracked the motion of neutral hydrogen gas in the galaxies and the filament, utilizing data from the Dark Energy Spectroscopic Instrument and the Sloan Digital Sky Survey. This research builds upon a 2022 discovery that filaments in the cosmic web are rotating, based on the motion of galaxies within them.
The finding that galaxies themselves spin in the same direction as the filament rotates is surprising, given how astronomers believe galaxies form. In our own Milky Way galaxy, gas, stars, and dust all rotate around the galactic center. It takes our Sun and solar system 220 million years to complete one orbit. The galaxy's rotation is influenced by the spinning cloud of gas that formed it 13 billion years ago, passing its angular momentum to the galaxy. However, close encounters, collisions, and mergers with other galaxies can disrupt a galaxy's spin.
The rotation of this specific filament appears to dominate the spin of the galaxies within it. This could be due to the filament funneling hydrogen gas along the dark matter filament, coercing the galaxies' spin while providing fuel for star formation. Tudorache explains, 'This filament is a fossil record of cosmic flows, helping us understand how galaxies acquire their spin and grow over time.'
The galaxies in this filament are relatively young and in the early stages of development, which could mean their spins may change as they mature. The fact that material flows along cosmic filaments can significantly influence galaxy properties is surprising and will require adjustments to models of galaxy formation.
This discovery also has implications for weak lensing surveys, which measure distortions in galaxy shapes and alignments caused by dark matter's gravitational lensing. Understanding the alignment and rotation of galaxies along these filaments will lead to more accurate measurements, aiding astronomers in mapping the cosmic web. The study's findings were published in the journal Monthly Notices of the Royal Astronomical Society on December 4.
Keith Cooper, a freelance science journalist and editor with a degree in physics and astrophysics, is the author of 'The Contact Paradox: Challenging Our Assumptions in the Search for Extraterrestrial Intelligence.' He has written extensively on astronomy, space, physics, and astrobiology for various magazines and websites.
