When and how did our Milky Way galaxy form? The question remains. But now astronomers say they've found the stars that started it all.
Over time, the Milky Way was built up through collisions with smaller galaxies. Until it gains a size that makes it above average in the local universe. Using the Gaia Space Telescope, AstronomersAstronomers It identified a number of stars that were once part of these dismantled galaxies. A complexity that makes it difficult to determine the original disk around which our Milky Way Galaxy evolved.
Stars 13 billion years old are already organized
But today, after dating a large number of stars in different parts of our galaxy, researchers from the Chinese Academy of Sciences and the University of Toronto (Canada) believe they have finally got their hands on this original disk. They called it PanGu “old record”But also like the Chinese god responsible for separating heaven from earth. And in the magazine Nature astronomyThey reported that it harbored stars blockblock The total is about 3.7 billion SunsSunsare produced at a constant rate over several hundred million years. They found some of these stars more than 13 billion years old. There will still be 2 billion solar masses in the disk. This represents only 0.2% of the current mass of our Milky Way Galaxy. Others exploded as supernovas.
If the researchers of this international team are right, then the original disk of the Milky Way was not in fact a disk. They show that it was indeed the first as high as it was broad. It flattened little by little, ending up at about a tenth of its height without changing its other dimensions much.
Should we revise theories of cosmology?
Hence, this proposal contradicts previous theories according to which the first stars appeared in the universe about 13.4 billion years ago. It's a bit like isolated points of light in a large area gasgas. And not directly inside structured galaxies that formed only about 12.5 billion years ago. Following violent collisions.
