Starship Asterisk*

In a first-of-its-kind analysis, Northwestern University astrophysicists have discovered that, contrary to previously standard lore, up to half of the matter in our Milky Way galaxy may come from distant galaxies. As a result, each one of us may be made in part from extragalactic matter.

Using supercomputer simulations, the research team found a major and unexpected new mode for how galaxies, including our own Milky Way, acquired their matter: intergalactic transfer. The simulations show that supernova explosions eject copious amounts of gas from galaxies, which causes atoms to be transported from one galaxy to another via powerful galactic winds. Intergalactic transfer is a newly identified phenomenon, which simulations indicate will be critical for understanding how galaxies evolve. ...

• Monthly Notices of the RAS 470(4):4698 (Oct 2017) DOI: 10.1093/mnras/stx1517
  arXiv.org > astro-ph > arXiv:1610.08523 > 26 Oct 2016