In 2014, the Hubble Space Telescope spied on the galaxy Large Magellanic Cloud, that rotate like clock. The LMC is a satellite dwarf galaxy of the Milky Way and among the closest galaxies to planet Earth
Now, astronomers reveal that like clockwork, all galaxies regardless of size or mass, rotate about once every billion years.
Gerhardt Meurer, from the International Centre for Radio Astronomy Research, and colleagues investigated a large number of galaxies ranging from small dwarf irregulars to massive spirals, with different sizes and rotational velocity.
After establishing a direct link between the size and average interior density of the galaxies, the researchers concluded that all galaxies behave like clocks and it takes about a billion years for them to make a complete spin, a discovery that researchers said they find weird.
"I just thought that's kind of odd, small galaxies and big galaxies all orbiting at the same time," Meurer said.
The researchers published their findings in The Monthly Notices of the Royal Astronomical Society on Wednesday, March 14.
"Galaxies behave as clocks, rotating once a Gyr at the very outskirts of their discs. Observations of a large optically-selected sample are consistent, implying this relationship is generic to disc galaxies in the low redshift Universe," the researchers wrote in their study.
Young Stars And Gas On Outskirts Of Galaxies
The researchers also discovered a significant number of much older stars among the young stars and gas, which is in conflict with theoretical models. The latter suggests that there would be sparse populations of interstellar gas and young stars on the outskirts of galaxies. However, Meurer and his team discovered a significant number of much older stars among the young stars and gas.
The researchers said that this discovery has implications in the field of astronomy. For one, it can help astronomers avoid wasting time and efforts when conducting studies of galaxies.
"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," Meurer said.
Meurer said that the next generation radio telescopes such as Square Kilometre Array, which will be the world's largest radio telescope to explore the universe, will have large amounts of data. Knowing the edge of the galaxy can help reduce the processing power required to sift through these data.