An illustration of the New Horizons spacecraft encountering 2014 MU69 – nicknamed Ultima Thule – a Kuiper belt object that orbits 1bn miles beyond Pluto. Photograph: emily.furfaro/Nasa/JHUAPL/SwRI
our billion miles from Earth, a swarm of little worlds circles the dark edge of our solar system. The sun is so remote from this place that it appears no brighter than a star. This is the Kuiper belt, a doughnut-shaped ring of icy objects that is one of the most mysterious – and one of the most scientifically intriguing – regions of space around our sun.
The belt is made up of rubble left over from the formation of the sun’s planets billions of years ago, fragments that are a fossil record of the solar system’s birth. For decades, researchers have dreamed of getting a close-up look at one but have been thwarted by the utter remoteness of the Kuiper belt.
But this sad state of scientific ignorance is about to come to an end. On 1 January, the US probe New Horizons – which has been hurtling away from the sun for the past 13 years – will sweep past Kuiper belt object 2014 MU69 and, for the next 24 hours, use its cameras, detectors and scanners to scrutinise this little world in detail. By the end of the probe’s encounter, an object that is currently no more than a dot in astronomers’ telescopes should be transformed into a world rich in astronomical and geological detail.
