Galaxies rotate once every billion years, study reports

Researchers that all galaxies rotate once every billion years, regardless of their size or density.
By Joseph Scalise | Mar 16, 2018
A group of astronomers from the International Center for Radio Astronomy Research have discovered that all galaxies rotate once every billion or so years, according to a new study published in the Monthly Notices of the Royal Astronomical Society.

This behavior holds true for every single type of galaxy, regardless of how big or small they are. The systems act like clocks and go through distinct cycles that can be traced throughout time.

"It's not Swiss watch precision," said lead author Gerhardt Meurer, a professor at the International Center for Radio Astronomy Research, according to International Business Times. "But regardless of whether a galaxy is very big or very small, if you could sit on the extreme edge of its disk as it spins, it would take you about a billion years to go all the way around."

The team in the study made the new discovery after using advanced calculations to look at the connection between size and the average interior density within different galaxy types. They found that if two galaxies are the same size, their interior density will also be the same.

Researchers also found aged stars sitting at the end of galactic disks. That confirmed such regions mark the end of galaxies. Such information is key because it will help astronomers better focus future research and not spend time or effort looking at places that will not produce usable data.

"This is an important result because knowing where a galaxy ends means we astronomers can limit our observations and not waste time, effort and computer processing power on studying data from beyond that point," added Meurer, in a statement. "So because of this work, we now know that galaxies rotate once every billion years, with a sharp edge that's populated with a mixture of interstellar gas, with both old and young stars."

The findings provide new insight into galaxies and help shed light on the universe as a whole. By studying never-before-seen mechanisms, astronomers can get a better idea of how different systems first came into being.

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