Jon M. Sweeney’s essay on the centrality of caring in the life of St Francis (“A kinship of harmony”, 20 June) reminded me of a small Beverly Hills dinner party my wife and I attended in the late 1970s. Among the guests was Willard Libby, the Nobel laureate who revolutionised archaeology with his discovery of carbon 14 dating. Also at the table were some NASA luminaries, enthusing about the triumphs of American space exploration. One of them asked Willard, “Dr Libby, what do you see as the meaning of what we have learned from our ventures into space?” “Meaning?” he growled in his deep, gravelly voice. “Well, we’ve been to the Moon and it’s dead. Looked at the planets, and they’re inhospitable or downright hostile to human l