One of the things scientists clearly have is the age of the universe: an estimated 13 700 million years ago is the date of origin of time. That is why it is exciting to discover new sky structures that confirm this view. Every new discovery, the age of which approaches the estimated age of the universe, stimulates astronomers. The latest finding has been made by a team of cosmologists from the University of Durham and the Harvard-Smithsonian Center for Astrophysics: it has found evidence that the weakest satellite systems around our own galaxy are one of the first galaxies in our universe.
Scientists who have worked on this research have described the finding as "enormously exciting," which explains that finding some of the first galaxies in the universe in orbit around the Milky Way "is equivalent to finding the remains of the first people who live on earth ". .
Segue-1, Bootes I, Tucana II and Ursa Major I are some of the first formed galaxies
In particular, the galaxies Segue-1, Bootes I, Tucana II and Ursa Major I are some of the first formed galaxies that are believed to be more than 13,000 million years old.
380,000 years after the Big Bang formed the first atoms. These were hydrogen atoms, the simplest element in the periodic table. These atoms gathered in the nebulae and gradually began to cool down to settle in the small groups or "halos" of dark matter that emerged from the big bang.
With the formation of the first galaxies, light was created in the universe, leading to the cosmic dark age, a known cooling phase that lasted about 100 million years to an end. Then the gas that had cooled down in the mists became unstable and began to form stars: these objects are the first galaxies that have been formed.
Video: Some of the oldest galaxies in the universe orbit around our Milky Way
Dr. Sownak Bose from the Harvard-Smithsonian Center for Astrophysics, who works with Dr. Alis Deason and Professor Carlos Frenk at the ICC at the University of Durham, identified two populations of satellite systems around the Milky Way.
The first was a very weak population that consisted of the galaxies formed during the "cosmic dark age" when there was still no sign of a star. The second was a slightly brighter population consisting of galaxies that formed hundreds of millions of years later, once the hydrogen that was ionized by the intense ultraviolet radiation of the first stars could cool in more massive halos of dark matter.
"Finding some of the first galaxies in orbit in the backyard of the Milky Way is the equivalent of finding the remains of the first people"
As detailed in Phys.org, the team discovered to their surprise that a model of galaxy formation that they had previously developed perfectly matched the data, allowing them to derive the age of the satellite systems.
According to Professor Carlos Frenk, director of the Institute of Computational Cosmology at the University of Durham: "Finding some of the first galaxies formed in our universe in orbit in the backyard of the Milky Way is the astronomical equivalent of finding the remains of The first people living on earth, it is very exciting. "
Source: very interesting / MF