The researchers found that there is a strong correlation between the age and shape of the Galaxy.
Over time, the galaxies in the entire universe have grown larger and weaker. The researchers found that the stars in a young galaxy move in an orderly manner, but as the galaxies get older, they become more fluffy and the stars are flying around.
A galaxy is a gravitationally bound structure that typically consists of gas, dust and billions of stars. Astronomers suggest there are more than 100 billion galaxies in the universe.
Although our knowledge of the universe has increased dramatically over the past decades with the help of satellites and ground-based studies, the formation and evolution of galaxies is still one of the most active areas of research. However, some concepts are widely accepted.
In an attempt to develop a complete picture of galaxy shape, researchers used an instrument called SAMI on the Anglo-Australian Telescope at the Siding Spring Observatory and measured the movement of stars within 843 galaxies of all kinds and masses. Based on observations, researchers found a strong correlation between a galaxy’s shape with its age.
“As a galaxy ages, internal changes take place and the galaxy may collide with others. These events disorder the stars’ movements,” said lead author Dr van de Sande from The University of Sydney.
“When we plotted how ordered the galaxies were against how squashed they were, the relationship with age leaped out. Galaxies that have the same squashed spherical shape, have stars of the same age as well.”
The correlation between shape and age was not confined to only extreme galaxies like very flat ones and very round ones, it was observed in all types of galaxies which may be spiral, elliptical or irregular.
“This is the first time we’ve shown shape and age are related for all kinds of galaxies, not just the extremes – all shapes, all ages, all masses.” Dr van de Sande said.
As the Anglo-Australian Observatory (AAO) is building SAMI’s successor instrument, Hector, researchers are hoping to observe more galaxies in greater detail and will search for the powerful relationships like shape and age that are hidden inside the complex structures of galaxies.