Dwarf Galaxy may have affect on Shape of Milky Way

Outer space is not far from Curtis Struck as images line the walls of his office. Struck, professor of physics and astronomy, has been at Iowa State for 28 years.

Katelynn Mccollough

Professor Curtis Struck is not new to the study of colliding galaxies. In fact, he has been studying them for 30 years, but a new discovery has caught his attention.

In the Sept. 15 issue of Nature, a weekly journal that focuses on science, Struck added his own commentary to a recent study pertaining to the idea that a dwarf galaxy may have had a more important impact on the shape to our very own galaxy, the Milky Way.

This dwarf galaxy, called the Sagittarius Dwarf Elliptical Galaxy, was discovered in 1994, but not much was known about it until closer studies done by Chris Purcell, from the University of Pittsburgh, and his research team looked into its effects on our galaxy.

“We think collisions and mergers are important in galaxies because they build them up,” Struck said, and explained that satellite galaxies often have quite a bit of dark matter associated with them. It is this dark matter that could possibly be what exerts change on a larger galaxy, such as the Milky Way. “These minor mergers don’t destroy, but change … it’s a gentler but longer term affect.”

Purcell and his research team believe that the dwarf galaxy in question may have had an influence on the spiral arms that shape the Milky Way and classify it as a barred spiral galaxy.

“When you’re inside a house, you know the rooms and can see outside the windows, but you can’t see the color of the house. That is what it is like to try and study our galaxy while we are inside it,” explained Brad Peterson, a lecturer in physics and astronomy, who has studied with Struck for seven years and obtained his Ph.D. from Iowa State last year. “The roll of minor mergers hasn’t been understood as well until recently.”

Astronomers have difficulty studying these dwarf satellites because they are too small to see in other galaxies, and we are not able to go outside of our own galaxy and look in. That doesn’t mean that their effects aren’t important. “This is the first inkling that a process like this may be important, but it will take more evidence for this to be expected,” Struck said.

Some students on campus, such as Michael Glawe, sophomore in pre-business, who has taken Astronomy 150, find these new discoveries fascinating.

“The universe is such an appallingly vast and mysterious place,” Glawe said. “Finding and learning about new galaxies gives me the perception that not any one country is pioneering, rather, humanity as a whole is setting those new frontiers with each discovery.”

There is the chance of more minor and major collisions in the future of our galaxy, but according to Struck, “These are many billions of years away.”