New insights from the Gaia spacecraft challenge our understanding of dwarf galaxies, which were previously seen as aged satellites encircling the Milky Way for billions of years.
Recent data from Gaia suggest that dwarf galaxies might be more fleeting and less influenced by dark matter than previously assumed. Contrary to the old belief, a study indicates that many dwarf galaxies might actually get destroyed shortly after entering the Galactic halo.
An international research team, analyzing the latest catalogue from ESA's Gaia spacecraft, has found evidence suggesting that dwarf galaxies might not be in a stable state.
These findings cast doubt on the traditional cosmological model, especially concerning the prevalence of dark matter in the immediate vicinity of galaxies.
For a long time, dwarf galaxies around the Milky Way were perceived as ancient satellites, presumed to have orbited our galaxy for nearly 10 billion years. This notion stemmed from the idea that their high-density dark matter shielded them from the immense gravitational forces exerted by our galaxy.
Furthermore, significant variations in star velocities within these dwarf galaxies were attributed to the presence of dark matter.
However, the Gaia data unveils a new perspective. Most dwarf galaxies have orbits much larger than the Sagittarius dwarf galaxy, which only entered the halo around 5-6 billion years ago. This suggests that the majority of dwarf galaxies might be relatively young, forming less than three billion years ago. This challenges previous assumptions about their age and composition, reshaping our understanding of these cosmic structures.
