“Surely, we can distinguish melted shrapnel from stones,” I noted during a Galileo Project research team meeting as we were planning the machinery for the Pacific Ocean expedition to retrieve fragments from the 2014 explosion of the first interstellar meteor. As shown in a recent paper (that I co-authored with Amory Tillinghast-Raby and Amir Siraj), air friction should have brought down the tiniest spherules just under to the explosion site and larger fragments farther along the original line of motion of the meteor up to its intersection with the ocean surface. The fragment size distribution depends on the unknown material...