Galaxies Dwarf Our Imagination: Study Unveils Their True Magnitude
Galaxies are significantly larger than initially believed, reaching vast distances into deep space—distances so great that our home galaxy, the Milky Way, probably comes into contact with our nearest galactic neighbor, Andromeda.
As you might imagine, the distance to the drugstore feels quite lengthy," penned Douglas Adams in The Hitchhiker's Guide to the Galaxy, "however, this pales in comparison to the vastness of space.
The cosmos is vast. Our home, Earth, resides as an insignificant speck circling a star located at the edge of our galaxy—a mere single entity among approximately two trillion galaxies within the observable universe. The scale of space is incredibly immense.
The planet Earth is situated within one of the spiral arms of the galaxy. Milky Way (referred to as the Orion Arm) situated approximately two-thirds of the way outward from the center center of the galaxy .
We are aware of the size of the Earth — approximately 12,756 kilometers (7,926 miles) in diameter. Similarly, we know the scale of our Sun, which measures around 1,391,000 kilometers (864,400 miles) in diameter.
However, just how large is our Milky Way galaxy? Up until this point, the actual dimensions of galaxies have been unknown.
Galaxies are far larger than we imagined.
A new study, published in the journal Nature Astronomy , has found that galaxies are far bigger than originally thought, perhaps several times bigger.
The spiraled structure of the galaxy we know is only the smaller core of the galaxy. For the Milky Way, this is about 100,000 light-years across.
The starlight emanating from stars located within the spiral arms reaches approximately 7,800 light-years out into the vastness of space, marking what was previously considered the boundary between a galaxy and outer space.
The research has shown that extensive "halos" of gas stretch beyond the observable spiral patterns 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 what we previously thought. interact with each other .
The research indicates that our Milky Way galaxy is probably colliding with our nearest 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 the environment around the galaxy. Over time, these areas merge with the larger cosmic web and connect with other galaxies. Such transitions typically have indistinct borders," stated 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?
Studying the gas halos from different types of galaxies — ones that form stars , or those that no longer form stars — will aid in understanding how galaxies accumulate mass over time, and what effects galaxies 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
