Its probably worth reading the last two paragraphs first: "There are other explanations, of course. One is that the fireball was of terrestrial origin, a remna

Its probably worth reading the last two paragraphs first: "There are other explanations, of course. One is that the fireball was of terrestrial origin, a remnant of one of the many asteroid impacts in Earth’s history that that have ejected billions of tonnes of rock and water into space, presumably with biological material inside. Another is that the structures are not biological and have a different explanation. Either way, considerably more work will have to be done before the claims from this team can be broadly accepted. Exciting times ahead!"