We all knew that galaxies rotate, but it wasn’t calculated how long does it take for a galaxy to rotate, but that has changed with a new study finding that all galaxies take around 1 billion years to rotate.
Just like Earth and billions of planets that rotate on their axis and revolves around the Sun once in a year, galaxies also rotate regardless of their size.
According to a new study conducted by a research team from the International Centre for Radio Astronomy Research (ICRAR), all disk galaxies, no matter big or small, take about a billion years to complete one spin while also adding that precision isn’t the key here.
“It’s not Swiss watch precision,” explained Professor Gerhardt Meurer from the International Centre for Radio Astronomy Research (ICRAR). “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.”
Meurer added that all galaxies that are the roughly the same size can be proved mathematically to have similar interior densities. He explained that it is not the case that a dense galaxy will rotate quickly, while another with the same size but lower density will rotate slowly.
Furthermore, Meurer and his research team also found that older stars lie on the edges of galaxies. While they were expecting to find only newly formed stars at the edge of the galactic disk, they found older stars along with the thin smattering of young stars and interstellar gas at the edges of the galaxies.
Meurer said that they are hopeful that the next generation of radio telescopes, such as the Square Kilometer Array, will give them “enormous” amounts of data to comb through which will help them better understand the evolution of our Universe.