Massive disk galaxies like the Milky Way are expected to form at late times in traditional models of galaxy formation, but recent numerical simulations suggest that such galaxies could form as early as a billion years after the Big Bang through the accretion of cold material and mergers. The Milky Way is a rotating disk-shaped galaxy, and is pretty stock standard for its age.
In most galaxy formation scenarios, galaxies only start to show a well-formed disk around 6 billion years after the Big Bang.

The thick disk is a source of early kinematic and chemical evidence for a galaxy's composition and thus is regarded as a very significant component for understanding galaxy formation. We present a scenario for the formation of disks that explains not only the properties of normal galaxies but also the properties of the population of low surface brightness galaxies (LSBs) as well. Published today in Nature, an international team of researchers has observed a massive, rotating disk galaxy just 1.5 billion years after the Big Bang—1.5 billion years earlier in cosmic history than astronomers had expected to find such a galaxy based on previous studies. Astronomy: Early disk galaxy puts formation models in a spin. We use a gravitationally self-consistent model for disk collapse to calculate the observable properties of disk galaxies as a function of mass and angular momentum of the initial protogalaxy. May 21, 2020. The fact that the astronomers found such a disk galaxy when the universe was only ten percent of its current age indicates that other growth processes must have dominated. The research has fuelled debate about how galaxies in the early Universe assembled. Nature. In most galaxy formation scenarios, galaxies only start to show a well-formed disk around 6 billion years after the Big Bang. This is much earlier than predicted by traditional models of galaxy formation, and adds to an ongoing debate about when and how disk galaxies, such as the Milky Way, form. “But the discovery of a massive disk galaxy just 1.5 billion years after the Big Bang tells us its formation may have followed a different path—possibly a cold-accretion model in which the infalling gas remained cold, allowing for the rapid condensation of the disk. A massive rotating disk galaxy that formed 1.5 billion years after the Big Bang is described in Nature this week. DISK GALAXY FORMATION IN A COLD DARK MATTER UNIVERSE Brant Robertson,1 Naoki Yoshida,2 Volker Springel,3 and Lars Hernquist1 Received 2003 December 19; accepted 2004 January 15 ABSTRACT We describe hydrodynamic simulations of galaxy formation in a cold dark matter cosmology, performed using a subresolution model for star formation and feedback in a multiphase interstellar …