Time evolution of the "light Sgr" satellite impact, from 2.65 billion years ago to the present-day. In this visualization, the multicolored disk is a 3D-density volume rendering, and the stars in the infalling Sgr satelilte are colored according to their total energy (indicating the degree to which they remain bound to the disrupting dark matter subhalo). Note the emergence of spiral structure in the MIlky Way disk as a response to the first disk crossing during infall.
credit: Erik Tollerud
source: [ Ссылка ]
