Unveiling the Biggest Spiral Galaxy in the Universe

Key Takeaways:

NGC 6872, located 212 million light-years away in the Pavo constellation, has been identified as the largest known spiral galaxy in the universe, surpassing the size of our Milky Way by five times.
The galaxy’s colossal dimensions, with a distance of 522,000 light-years between its two spiral arms, were revealed through comprehensive analysis of data collected by various instruments, including NASA’s Galaxy Evolution Explorer spacecraft (GALEX).

GALEX’s ability to detect ultraviolet light from young, hot stars played a crucial role in uncovering the full extent of NGC 6872’s size and structure.
NGC 6872’s peculiar appearance and vast proportions are attributed to gravitational interactions with its neighbor galaxy, IC 4970, which has only 20 percent of its mass.
Computer simulations suggest that about 130 million years ago, IC 4970’s close approach triggered significant activity in specific regions of NGC 6872, leading to disturbances and heightened star formation.

This composite of the spiral galaxy NGC 6872 combines visible light images from the European Southern Observatory’s Very Large Telescope with far-ultraviolet data from NASA’s GALEX and infrared data acquired by NASA’s Spitzer Space Telescope. The spiral is 522,000 light-years across from armtip to armtip, which makes NGC 6872 about 5 times the size of the Milky Way. (Image credit: NASA’s Goddard Space Flight Center/ESO/JPL-Caltech/DSS)

In a groundbreaking discovery, astronomers have identified NGC 6872 as the largest known spiral galaxy in the universe, residing an astonishing 212 million light-years away in the southern constellation Pavo. This celestial giant surpasses our own Milky Way by an astounding factor of five, marking a significant milestone in our understanding of galactic structures.

NGC 6872’s massive proportions were brought to light through meticulous analysis of data gathered by various instruments, with NASA’s Galaxy Evolution Explorer spacecraft (GALEX) playing a pivotal role. The spacecraft’s unique ability to detect ultraviolet light emitted by the youngest and hottest stars enabled scientists to comprehend the full scope of NGC 6872’s intricate system.

Lead scientist Rafael Eufrasio, affiliated with NASA’s Goddard Space Flight Center and the Catholic University of America, presented these groundbreaking findings at the 221st meeting of the American Astronomical Society in Long Beach, California. Emphasizing the significance of GALEX’s contribution, Eufrasio acknowledged that without its capabilities, the true extent of NGC 6872 might have remained elusive.

NGC 6872’s colossal size and distinctive appearance are attributed to gravitational interactions with its neighboring galaxy, IC 4970, a celestial companion possessing a mere 20 percent of NGC 6872’s mass. Through computer simulations, researchers deduced that IC 4970’s closest approach occurred approximately 130 million years ago, provoking a surge of activity within specific regions of NGC 6872.

The Milky Way Galaxy is organized into spiral arms of giant stars that illuminate interstellar gas and dust. The sun is in a finger called the Orion Spur.

A noteworthy feature of NGC 6872 is its enormous bar, linking the galaxy’s arms and central regions. With a radius of 26,000 light-years, this bar is twice the size of bars found in nearby spiral galaxies. Intriguingly, no recent evidence of star formation is apparent in NGC 6872’s bar, suggesting its formation transpired billions of years ago.

The intricate dance between NGC 6872 and IC 4970 offers a glimpse into the dynamic processes shaping galaxies over cosmic timescales. While NGC 6872 now claims the title of the largest spiral galaxy, astronomers acknowledge the possibility of even larger spirals awaiting discovery and detailed exploration. As our understanding of the universe’s vast tapestry continues to unfold, NGC 6872 stands as a colossal testament to the marvels that await exploration in the cosmic realm.