Planetoid a billion miles beyond Pluto selected as New Horizons’ next destination

Following on from its historic flyby of Pluto in July, NASA has selected the next potential destination for the unmanned spacecraft, a planetoid called 2014 MU69 that lies a billion miles beyond Pluto’s orbit. The probe will take over three years to reach the frozen remnant of the Solar System’s earliest years.
Technically a small Kuiper Belt object, 2014 MU69 has been given the nickname "PT1" or "Potential Target 1" by the New Horizons team. According to NASA, it’s less than 30 mi (45 km) in diameter and 10 times larger and 1,000 times more massive than a typical comet. It’s this small size that makes it of interest to scientists, who regard PT1 as a leftover building block of the Solar System that’s been preserved in the cold darkness of deep space and hasn’t changed much in 4.6 billion years.
PT1 was one of several potential targets under consideration by the New Horizons team after a search going back to 2011. Earth-based telescopes weren’t up to the job of choosing a candidate that was both interesting and within New Horizons’ range, so the Hubble Space Telescope was used. It uncovered five candidates, which were then reduced to two, and now one.