ur galaxy which we are starting to more commonly refer to as home has never been assigned a specific age as we simply didn’t know when it was created. Astronomers have been speculating that it occurred quite soon after The Big Bang took place about 13.8 billion years ago. In a very small fraction of a second known as the Planck period, the universe was created. Its high instability and the extreme heat created by the big bang forced the universe to expand.
However, very recently astronomers Maosheng Xiang and Hans-Walter Rix of the Max-Planck Institute for Astronomy have published a paper in the journal Nature that outlines the exact age of our galaxy. The astronomers used a survey of nearly a quarter of a million start to discover the development of our galaxy. They also used existing knowledge of stellar lifecycles to better understand the longer galactic lifecycle within the universe.
The spiral that represents our galaxy known as the Milky Way can be split into two different groups of cosmic bodies. The thick inner disk within the spiral represents the younger stars in which our sun is identified. The other disk is thicker and covers mainly the outer layer of the spiral houses the older starts. From this Xiang and Rix have acknowledged that the thicker disk from the spiral started forming around 13 billion years ago.
This makes our galaxy 13 billion years old from a different perspective, we can say that our galaxy has been formed 800 million years after The Big Bang. The development was further reinforced when Milky Way devoured a whole different galaxy. What happened about 11 billion years ago is a merge between the Gaia-Enceladus galaxy and Milky Way galaxy. Due to the size of our galaxy, it had sort of eaten this dwarf galaxy that interfered during the expansion process of the universe.
What helped the researchers to make the discovery was stellar clocks which are low mass stars in the “sub-giant” phase. The main challenge was finding stellar clocks as stars usually spend only a few million years in the sub-giant phase and to calculate the age of our galaxy they needed a data set of at least 100,000 stellar clocks.
With the use of the European Space Agency’s Global Astrometric Interferometer for Astrophysics spacecraft known as Gaia and the Large Sky Area Multi-Object Fibre Spectroscopic Telescope in China known as Lamost, the researchers were able to survey 247,104 stars in the sub-giant phase. These results were not only a major breakthrough for identifying the age of our galaxy, but they will be very useful for future studies that are looking to better understand the formation of galaxies.
Data has once again proven that it is the key to understanding our history, the creation of our world, and hopefully one day the meaning of life. Our world, the galaxy, and the universe as a whole are constantly evolving and the universe is still expanding even after 13.8 billion years which raises the question if we will ever merge with another galaxy in the far future.
Avid Writer with invaluable knowledge of Humanity!
Upcoming historian with over 30 million views online.
“You make your own life.”
