A team of astronomers has concluded through their new study that the Milky Way evolved after merging with neighboring galaxies. Research conducted by experts at the Harvard-Smithsonian Center for Astrophysics (CfA), who even proposed that our Milky Way, after merging with two dwarf galaxies heading towards it, the Large Magellanic Cloud and the Small Magellanic Cloud, will Going through another evolutionary stage in the future.
Modern cosmological theories suggest that galaxies in our universe share a common evolutionary process in which they collide and merge with other systems. Experts, who published their findings in The Astrophysical Journal, say our Milky Way galaxy provides the clearest view of the theory.
The Milky Way underwent a merger billions of years ago
Billions of years ago, a dwarf galaxy collided and merged with the Milky Way, researchers using data from the Gaia spacecraft have revealed. Launched in 2013, the Gaia spacecraft was designed to create an accurate three-dimensional map of our galaxy by measuring only 1% (approximately) of the 100 billion stars. The astronomers reportedly combined the Gaia data with data from the 6.5m MMT telescope in Arizona used for the “H3 Sky Survey” of stars in the Milky Way. Combining data from both, astronomers concluded that the dwarf galaxy Gaia-Sausage-Enceladus (GSE) merged with the Milky Way about 8 to 10 billion years ago.
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Although experts thoroughly observed the dwarf galaxy’s stars, which are now intermingled with the Milky Way’s stars, they were unable to determine whether the GSE merged with the Milky Way after orbiting the Milky Way or just collided head-on.
To determine exactly what happened, experts used Gaia’s observations and computer simulations to create a model of the early universe. According to the study, the model shows that the GSE galaxy, which contains 5 billion stars, is moving in the opposite direction to the Milky Way, rather than orbiting and gradually blending into it. The model also depicts that many of the Milky Way’s stars are about 13 billion years old and were once part of dwarf galaxies. In addition, the scientists concluded that nearly 20% of the Milky Way’s dark matter and 50% of the Milky Way’s current stellar halo is the contribution of the GSE.
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