Computers built with analogue circuits promise huge speed and efficiency gains over ordinary computers, but normally at the cost of accuracy. Analogue computers that rapidly solve a key type of equation used in training artificial intelligence models could offer a potential solution to the growing energy consumption in data centres caused by the AI boom. Laptops, smartphones and other familiar devices are known as digital computers, because they store and process data as a series of binary digits, either 0 or 1, and can be programmed to solve a range of problems. In contrast, analogue computers are normally designed to solve just one specific problem. They store and process data using quantities that can vary continuously such as electrical resistance, rather than discrete 0s and 1s.

Google's Doodle is celebrating the Antikythera mechanism, which might just be the first computer. The mechanism was found in 1902 – exactly 115 years ago – and the discovery changed the way we saw the ancient Greeks. The man who found it, Valerios Stais, initially thought that the bronze mechanism he could see was a gear or a wheel – but on closer inspection, the metal turned out to be part of the Antikythera mechanism, an ancient and mysterious analogue astronomical computer. The machine could be used to track and predict where the planets were, understand lunar and solar eclipses, and count towards the next Olympic Games. But its uses were various – it might also have been used for unknown forms of mapping and navigation.