I just noticed that the meteorite fragments in the second photo are sitting on aluminum foil (as the top one is more obviously). So kudos to both groups for knowing the recommended procedure for keeping a fresh meteorite as uncontaminated as possible.
I don’t know. Three witnessed, recovered falls in three days has never happened before (I don’t know if three in three months has happened before.). It is conceiveable that we could spend days passing through the debris of one asteroid breakup–after all, periodic meteor showers are spread out over several days.
All being witnessed falls, they will be able to calculate the rough orbit of each of them, and they will all be studied in great detail (including with ion microprobes) and know if they came from the same parent body, so we will have a definite answer soon. I’m guessing really freaky coincidence because randomness is lumpy, though.
I’m no expert, but the Texan one looks like a very different composition than the Italian one: I’d guess that the Texan one is mostly iron, while the Italian one looks like chondritic. Though some space-rocks are a mixture of both, so that doesn’t rule out them being a larger object that broke up.
When the Peekskill meteor fell back in 1992, it was a tremendous stroke of luck that it fell in America on a Friday evening in October, because it meant that there were a lot of people outdoors with camcorders, recording high school football games, and so we had multiple video recordings of the fall, which was then unprecedented. Nowadays, though, with everyone carrying a movie camera in their pocket, I guess that’s become routine.
No, and no. There can be some slight enrichment in radioactive elements on the very surface of the meteoroid thanks to cosmic rays hitting atoms and to a dusting of solar wind particles (the same way the moon accumulates the much mentioned tritium) but it would be trace amounts and that part of the meteoroid would ablate away before it hits the ground anyway. Meteorites are made from the exact same elements as the Earth itself, and the radioisotopes in them have gone through the same number of half-lives.
(Which leads to one “maybe”. In theory, a meteorite could fall that was tossed out of a very young, nearby solar system that contained an abundance of newly cooked radioisotopes from a recent supernova. But having that happen is–how should I put it–somewhat unlikely.)