A new twist has been added to Sagan's "We are made of star stuff." In The Lost Galaxies, Scientific American, May 2011, James Geach explains baryon cycling. Galaxies are not fixed groups of baryons, he says, but a small component of the large-scale evolution of the intergalactic medium. While gravity pulls baryons out of the warm-hot intergalactic medium into galaxies, they are shot back out by solar wind, supernovas, and jets. "Matter within your fingernail could have spent billions of years exiled in intergalactic space before coming to rest in our solar system." "...up to half of the baryons currently locked into galaxies in the local universe have cycled through the intergalactic medium at least once and often many times." Some of the matter in our bodies would have come from other galaxies. So we're even more connected to the larger universe than we thought. Neat!

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