The Andromeda Galaxy, a neighbor of the Milky Way that our solar system is part of, was formed by a huge collision between two smaller galaxies, about three billion years ago, when Terra was already there, according to a study quoted by Mediafax .
Calculation of the moment when this galaxy appeared was a big challenge for astrophysicists, given the large differences in the age of the stars that formed it.
For the new study, published in the Monthly Notices of the Royal Astronomical Society, French and Chinese researchers, coordinated by François Hammer of the Paris Observatory, used "the most powerful computerized systems in France" to analyze a terabyte of data.
This analysis allowed them to see in depth "the physical mechanisms involved in Andromeda's formation and to find information about its origin," said an observer's statement.
Previous studies have demonstrated a major difference between our galaxy and Andromeda - long thought twins, the researchers said.
In Andromeda, some stars chaotic orbit, while in the Milky Way all the stars rotate around the center of the galaxy.
According to the new study, in Andromeda the stars move chaotically because this galaxy is younger.
The data showed that 7 to 10 billion years ago, two galaxies - four times larger than the other - were on a collision course.
The researchers simulated their trajectories and concluded that they merged 1.8 - 3 billion years ago, resulting in Andromeda