A new study claims we might all be part-alien.
Supercomputer simulations conducted by a team of astrophysicists at Northwestern University suggest that each of us -- and everything in our galaxy -- may have been expelled vast distances across the universe by exploding supernovas.
Thrown into space with such force, streams of charged atoms are blasted away from their original galaxy's gravitational pull and carried to our Milky Way on "powerful galactic winds."
Daniel Angles-Alcazar, a postdoctoral fellow at Northwestern in Illinois who led the study, told CNN that the team created intricate 3-D models which allowed the team to explore the evolution of galaxies over time.
"We ran highly sophisticated simulations, looking at the formation of galaxies from shortly after the Big Bang and traced their development to today," Angles-Alcazar said, continuing "We found that when we completed these simulations that we could say ... that the atoms which formed the solar system and so which form us, may have existed in other galaxies."
The astrophysicists published their findings, which took the equivalent of "several million hours of continuous computing," in the Monthly Notices of the Royal Astronomical Society's journal.
The simulations identified a new phenomenon of "intergalactic transfer" facilitated by gas traveling at high speeds to separate neighboring galaxies. Before these simulations, it was thought galaxies largely grew by absorbing material left over by the big bang.
"We knew about galactic winds from previous models but this transfer of mass that we've identified is a fresh result for us," Angles-Alcazar said.
Claude Faucher-Giguere, another astronomer on the team, said in a statement that the computer models implied that "up to one half of the atoms around us" came from galaxies "up to one million light years away."
The process of intergalactic transfer is likely to have taken several billion years, according to the Royal Astronomical Society.
Andromeda -- our nearest galactic neighbor-- is located about 2.5 million light-years from Earth.
"Given how much of the matter out of which we formed may have come from other galaxies, we could consider ourselves space travelers or extragalactic immigrants," Angles-Alcazar said.