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Riverside, Calif. (Sept. 2, 2015) -- Dr. Kyle Stewart's theoretical prediction of a "gas spinning disk" that helps build a galaxy into a bigger one has been confirmed. It took two years of progressive research to validate his theory.

Galaxy formation is an elaborate affair and something Stewart has studied for almost 10 years.

"We still don't fully understand all the physics involved in the process of galaxy formation," said Stewart, assistant professor of physics.  

Dr. Kyle StewartStewart said scientists have run computer simulations to approximate how galaxies are formed for a long time. They recognize that cold gas is involved in the process but thought it had no structure. The idea was that gas falls into galaxies from all sides and then eventually that gas transforms into stars, he said. 

More recent simulations showed something else. In papers published in 2011 and 2013, Stewart co-authored a study that claimed that gas can create a "spinning cold-flow disk." This disk increases many times larger than the galaxy and then becomes the structure needed for a galaxy to expand. The gas is funneled into this disk by filaments, galactic string-like structures. 

In 2014, a galaxy and filament were observed. A team of researchers took a closer look through a spectrograph, which takes light from a source and separates it by wavelength.

These researchers determined that half the gas moved toward the disk and the other half moved away from the disk, indicating a cold-flow disk. Their study was published last month in the international science journal Nature, validating Stewart's prediction.

"It confirms the whole new picture of how we think galaxies are formed," Stewart said. "This is a big verification that the simulations are doing something right."

Stewart is also doing similar simulations with different programming codes to see if the results are the same.

"They are finding that the details vary, but the disk phenomenon seems to happen no matter the code," Stewart said.

Stewart said astronomers can predict something and maybe a decade later will find out if they are right.

"To make a prediction and have it confirmed two years later is an amazing experience," he said. 

"We're just now starting to get a picture of galaxy formation," he said. "It's an emerging field that didn't exist until Hubble Telescope began taking pictures and giving us thousands of galaxies to look at."