XCHAOS: The rocket which created this debris was launched by SpaceX from the Vandenberg Air Force Base in California on 1 February.
"It was supposed to re-enter the Earth's atmosphere in a controlled manner and crash into the Pacific Ocean," Harvard University astrophysicist Dr Jonathan McDowell told the BBC.
"But the engine failed. We've seen it orbiting Earth for the past few weeks and we were anticipating an uncontrolled re-entry today, which is what people saw burning in the sky.