Science, Maths & Technology
Pluto comes into sharp focus – but it’s still not a planet
...works for ours and is a far neater approach than including every Kuiper belt object as a planet – thousands of them, which would be ridiculous. The alternative of defining a size or mass minimum at which an object ceases to be a planet would suffer from our variable and imperfect ability to measure their size or mass remotely. [Image of the Kuiper Belt. The background...