Astronomers believe at least two dwarf galaxies, which are collections of gases between 100 to 1,000 times smaller than the Milky Way Galaxy, will soon merge. If this merger does occur, it would be a first in the history of astronomical observation. While it’s common for large or even medium galaxies to collide, astronomers have yet to observe small dwarf galaxies do the same.
So, what’s leading so many astronomers to anticipate this major event? Well, it mainly has to do with a new study revealing seven heretofore unknown clusters in outer space. All of these clusters contain dwarf galaxies. Since the clusters are located so close to one another, most researchers believe at least two of these galaxies will merge at some point. Most importantly for the astronomical community, this finding has confirmed two hotly debated theories.
How Astronomers Discovered These Dwarf Galaxies
Sabrina Stierwalt, a member of the National Radio Astronomy Observatory in Charlottesville, Virginia, deserves all the credit for this huge discovery. Stierwalt and colleagues used optical telescopes as well as information from the Sloan Digital Sky Survey (SDSS) to discover these clusters of dwarf galaxies close to the Milky Way.
First of all, Stierwalt and her team looked through the SDSS data for dwarf galaxies that could potentially interact. Once the astronomers found a few images of dwarf galaxies, they went on to examine whether or not each pair was already a part of some larger assemblage.
To gather even more data, researchers used the Magellan telescope in Chile, the Gemini telescope in Hawaii, and the Apache Point Observatory in New Mexico. The researchers working with these prestigious telescopes were able to confirm that all the dwarf galaxies they observed in the SDSS were gravitationally bound together.
Long before Stierwalt made her discovery, another reputable astronomer predicted dwarf galaxies must combine within a few years. Elena D’Onghia, a professor at the University of Wisconsin, said that dwarf galaxies must collide, otherwise the theory of gravity could be proven to be invalid. In 2009, D’Onghia said,
Based on dark matter theory, we expect a lot of little dwarf galaxies and clumps of dark matter in and around the Milky Way.
As Stierwalt’s findings point out, the collision of two dwarf galaxies is almost a certainty in the near-term future.
Two Theories Confirmed From Dwarf Star Data
The discovery of these clusters helps astronomers better understand the nature of our own universe. Since these seven clusters are very close to our own Milky Way, many now believe the theory that galaxies form due to collisions is completely valid. While many astronomers believed in this theory for years, there was no solid evidence to prove it until now.
Stierwalt’s findings have also led scientists to believe that invisible dark matter is distributed in tiny patches across the whole universe. One professor at the University of Texas, Mike Boylan-Kolchin, explained to reporter that it’s the gravity contained within dark matter that holds all dwarf galaxies together. As Boylan-Kolchin put it, all of these galaxies “are living in dark matter haloes.”
Stierwalt’s Findings Are Only The Beginning
Although these findings are groundbreaking in the field of astronomy, Stierwalt hopes her work is only the staring point for understanding galaxy formation and dwarf galaxies. She told journalists that she is excited for what future astronomers will be able to discover as technology improves.
Stierwalt’s paper was published in the latest edition of Nature Astronomy under the title “Direct evidence of hierarchical assembly at low masses from isolated dwarf galaxy groups.” Future research in all things related to our current knowledge of the cosmos will be greatly boosted by this event.