3I, the interstellar object that’s baffling astronomers
Science began in the skies. Just after sunset, to be exact, on the evening of November 11, 1572 when a young Danish nobleman, Tycho Brahe, raised his eyes to the night sky. There, above his head, a star was shining brighter than all the rest – a new star that should not have been. Brahe thought he was mistaken, that his eyes were playing tricks on him, but others confirmed what he saw. And yet, according to the reigning theory, derived from Aristotle, there could be no change in the eternal heavens. Surely then this object could not be a star. It must be an anomaly in the upper atmosphere, closer to the Earth, within terrestrial realms. But Brahe got to work. Using trigonometry and observations, he found that the impossible had indeed occurred.