Recently a team of astronomers has discovered some of the oldest galaxies in the whole wide universe, some of them are more than 13 billion years old. These galaxies actually started forming "only" about 100 million years after the Big Bang.
According to the experts, when the universe was around 380,000 years old, the first atoms -- hydrogen atoms -- were created. Hydrogen atoms, as we know it, are periodic table's simplest element. After the early formation, these atoms gathered together, shaped clouds and started to slowly cool off. Then they settled inside these "halos" of dark matter, which essentially came out of the Big Bang.
This cooling period in science is known as the "cosmic dark ages." It lasted for about 100 million years. In due course, the gas inside those halos, which had cooled, started getting unstable and creating stars. Those objects were the first ever galaxies to have formed. As soon as the first galaxies were formed, the universe just burst into light and that ended the cosmic dark ages.
These galaxies, which were the oldest ones that the experts on Earth have found, are not situated very far from our very own Milky Way. They are more or less located in the orbits around and near our galaxy.
The co-author of the study, which was published in Astrophysical Journal, Carlos Frenk from the Durham University said, "Finding some of the very first galaxies that formed in our universe orbiting in the Milky Way's own backyard is the astronomical equivalent of finding the remains of the first humans that inhabited the Earth. It is hugely exciting."
The researchers also said that their recent discovery falls in line with the model of the galaxy creation, which they had developed.
According to Sownak Bose, the lead author of the study at the Harvard-Smithsonian Center for Astrophysics, "A decade ago, the faintest galaxies in the vicinity of the Milky Way would have gone under the radar." It's because of today's latest and better sensing techniques that "a whole new trove of the tiniest galaxies has come into the light, allowing us to test theoretical models in new regimes," Bose added.