Looking up at a clear night sky over Britain often inspires a sense of wonder, but the cosmos still holds plenty of intriguing secrets. For nearly three decades, astronomers assumed a passing space rock named 1998 SH2 was merely a standard asteroid. However, groundbreaking findings titled Non-gravitational Acceleration Indicative of Cometary Activity of Near-Earth Object, published in Nature Astronomy, revealed that this mysterious near-Earth neighbour is actually a hidden, gas-venting comet.