Science, Maths & Technology
Pluto comes into sharp focus – but it’s still not a planet
...system’s ninth planet upon discovery by Clyde Tombaugh in 1930. He’d been looking for a planet where faulty data suggested a planet-sized body was perturbing the orbit of Neptune. This, he felt, was it – and the world agreed. Pluto’s mass was at first thought to be roughly the same as the Earth’s, but by 1948 estimates had shrunk it to the size of Mars. When...