Ian O'Neill: "After pulling together the nominations by considering web traffic over the past 12 months, the selection was put up for a vote across social media and the top 10 quickly became obvious -- with a very clear winner."
The supermassive black hole is 40 million times as massive as the sun and powers a quasar that existed 700 million years after the Big Bang.
The asteroid zoomed by Earth at a perfectly safe distance of around 1.8 million miles (2.9 kilometers).
Images show surprise changes to the spacecraft as it interacted with the atmosphere.
