The birth of our galaxy, 5 billion after the Big Bang – Guido Tonelli /Courier TV
The universe is now populated by the light of the stars, in the heart of which the metals are produced, which will form the nuclei of carbon, nitrogen, iron … When the great stars of the first generation explode, they will scatter these elements all around; and those substances will aggregate in the form of stars and planets. Those stars, those planets are structured in wonderful shapes: galaxies. Ours is formed 5 billion years after the Big Bang. At the center of galaxies are often the “black stars”, black holes, with gigantic masses, around which these enormous structures revolve. In our case, the “black hole” around which we rotate is called Sagittarius A, with a mass 40 times that of the Sun.