Galaxies Dwarf Our Imagination: Study Unveils Stunning Scale
Galaxies are significantly larger than initially believed, stretching vast distances into deep space—such extensive reaches mean that our Milky Way probably comes into contact with our nearest galactic neighbor, Andromeda.
As you might imagine, the journey to the drugstore feels quite lengthy," penned Douglas Adams in The Hitchhiker's Guide to the Galaxy, "however, this distance is negligible compared to the vastness of space.
The vastness of space is immense. Our home, Earth, resides on this minuscule planet circling a star located deep within our galaxy, which itself is merely one among an estimated two trillion galaxies in the observable cosmos. The scale of space truly defies comprehension.
The planet Earth is situated within one of the spiral arms of our galaxy. Milky Way (referred to as the Orion Arm) which is located roughly two-thirds of the way outward from the center center of the galaxy .
We are aware of the size of the Earth — measuring at 12,756 kilometers (7,926 miles) in diameter. Similarly, we also know the scale of our Sun, which spans approximately 1,391,000 kilometers (864,400 miles) in diameter.
However, just how vast is the Milky Way? Up until this point, the actual dimensions of galaxies have been an enigma.
The size of galaxies exceeds our initial expectations.
A recent research paper, featured in the journal Nature Astronomy It has been discovered that galaxies are much larger than initially believed, possibly even multiple times their original estimates.
The spiral shape of our galaxy represents just the compact central region. In the case of the Milky Way, this spans approximately 100,000 light-years.
The starlight emanating from stars located within the spiral arms reaches approximately 7,800 light-years out into deep space, marking what was previously believed to be the boundary between a galaxy and outer space.
The research has shown that extensive "halos" of gas stretch beyond the observable spiral arms of stars deeply into outer space.
Astronomers were able to observe these gaseous halos for the first time thanks to advanced imaging technologies. These techniques allowed scientists to identify galactic gas halos extending more than 100,000 light-years into space, significantly expanding our understanding of the size of galaxies.
Kissing galaxies
Actually, the halos of gas from galaxies reach so far into deep space that galaxies themselves extend beyond their visible boundaries. interact with each other .
The research indicates that our Milky Way is probably colliding with our nearest galactic neighbor, Andromeda, which is approximately 2.5 million light-years distant, as stated by Nikole Nielsen, the lead author of the study and a researcher at Swinburne University in Australia.
"As we observe now, this marks the edge of the galaxy’s sphere of influence, transitioning into regions dominated by external forces from surroundings such as neighboring galaxies. Over time, these areas merge with the larger cosmic network encompassing numerous galaxies,” explained Nielsen in a media release.
Researchers believe this finding will aid in unraveling one of the most significant mysteries in astronomy: how galaxies develop over time?
Examining the gas halos surrounding various kinds of galaxies — those form stars , or those that no longer form stars — will aid our understanding of how galaxies accumulate mass over time and the effects they have on one another during interactions.
Edited by: Andreas Illmer
Primary source:
Nielsen, N.M., et al. A map showing emissions from the interface between the disk and circumgalactic medium in the starburst galaxy IRAS 08339+6517. Nature Astronomy (2024). https://www.nature.com/articles/s41550-024-02365-x
Author: Fred Schwaller