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Half of the Milky Way is From Somewhere Else

If your doctors can’t figure out what’s wrong with you, don’t blame them … blame the universe. A new study found that half of your body, not to mention half of everything around you, comes from a galaxy other than the Milky Way. No wonder we have so many half-assed half-wits pushing half-baked theories full of half-truths and half-cocked schemes. Blame it on the halves from Andromeda.

Actually, the theory is not as half-baked as it sounds. Daniel Anglés-Alcázar, the leader of the study published this week in the journal Monthly Notices of the Royal Astronomical Society, points to galactic winds as the culprit.

“It is likely that much of the Milky Way’s matter was in other galaxies before it was kicked out by a powerful wind, traveled across intergalactic space and eventually found its new home in the Milky Way.”

A long time ago from a galaxy far, far away …

His team at the Northwestern University astrophysics center, CIERA (Center for Interdisciplinary Exploration and Research in Astrophysics), developed a supercomputer model to simulate various scenarios of how galaxies were formed in order to study wind recycling. Let your imagination run wild on that phrase for a minute. Finished? Wind recycling occurs when galactic winds are formed by supernovae and push gas particles around at high speeds. Some of this wind leaves the supernova’s galaxy, but a small amount gets sucked back in and used again – wind recycling. Did your imaginary picture of it involve deep breathing and a crowded galactic elevator?

As is the case in so many simulations, what the scientists found had nothing to do with what they were looking for. The models showed that the wind frequently escapes from its own galaxy and travls billions of light years across space to be absorbed in other galaxies and form new stars. . For some reason, this flow occurs most often from small galaxies to larger ones. Anglés-Alcázar got to name this phenomenon “intergalactic transfer.”

“It was actually surprising for us to find out that there is that much exchange of mass between galaxies.”

Which one are you from?

How much is ‘that much’? The simulations showed that a galaxy like the Milky Way (do we really care that much about the other ones?) got half of its matter from other galaxies. The disbelieving researchers checked their figures by converting the simulations to 3-D and the intergalactic transfer produced the same results … in 3-D.

For those who want to be space travelers but don’t think it will happen in their lifetime, Anglés-Alcázar has good news for you.

“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.”

If we’re all extragalactic immigrants on this planet, isn’t it time we stopped pointing fingers and started getting along?


Paul Seaburn is the editor at Mysterious Universe and its most prolific writer. He’s written for TV shows such as "The Tonight Show", "Politically Incorrect" and an award-winning children’s program. He's been published in “The New York Times" and "Huffington Post” and has co-authored numerous collections of trivia, puzzles and humor. His “What in the World!” podcast is a fun look at the latest weird and paranormal news, strange sports stories and odd trivia. Paul likes to add a bit of humor to each MU post he crafts. After all, the mysterious doesn't always have to be serious.
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