The first galaxies of the Universe are thought to have formed at the sites where a lot of dark matter gathered, leading to the gravitational pull to pull in enough ordinary matter to create the stars. And even today, it’s impossible to explain the behavior of almost all the galaxies that we have observed without saying that they have an essential dark matter component.
However, nearly but not all of them. A number of galaxies have been observed that are dim and diffused and seem to have somewhat less dark matter. These galaxies couldn’t be understood for a period, putting forward questions about whether the observations had provided a detailed picture of their composition. However, experimenters have newly observed one way the galaxies could form. A minor galaxy could be wiped out by a larger one that maintains the dark matter and spits out the stars.
The new work depends on broadening the mechanism implicated in creating the Bullet Cluster down to the scale of individual galaxies. Physics works the same way. A collision hits normal matter into a messy clash that’s driven by its interactions, while dark matter enacts smoothly through the mess. It’s not clear how much of the formal matter structures can survive this sort of trash. But, because there can be a ton of gas present after the dark matter has moved on, it’s possible that the ordinary matter can form structures that require a dark matter component.
The recent research pertains this logic to the two best-established dark matter-free galaxies, named DF2 and DF4, which are small galaxies that prevail near a normal, huge galaxy named NGC 1052.