Al-Jallad began pulling up every inscription that mentioned migrating in search of rain, and soon he had a long list of terms that had resisted translation. Comparing them with the Greek, Aramaic, and Babylonian zodiacs, he started making connections. Dhakar matched up nicely with dikra, the Aramaic word for Aries, and Amet was derived from an Arabic verb meaning “to measure or compute quantity”—a good bet for the scales of Libra. Hunting for Capricorn, the goat-fish constellation, Al-Jallad found the word ya’mur in Edward Lane’s “Arabic-English Lexicon,” whose translation read, “A certain beast of the sea, or . . . a kind of mountain-goat.” He stayed up all night, sifting the database and checking words against dictionaries of ancient Semitic languages. By morning, he had deciphered a complete, previously unknown Arabian zodiac. “We’d thought that they were place names, and, in a way, they were,” he told me. “They were places in the sky.”