The Unexpected Trajectory of Interstellar Asteroid 'Oumuamua

Explanation: Why is 'Oumuamua differing from its expected trajectory? Last year, 1I/2017 U1 'Oumuamua became the first known asteroid from interstellar space to pass through our Solar System . Just over a year ago, this tumbling interstellar rock even passed rather close to the Earth . The asteroid's future path should have been easy to predict given standard gravity -- but 'Oumuamua's path has proven to be slightly different. In the featured animation , 'Oumuamua is shown approaching and exiting the vicinity of our Sun , with the expected gravitational and observed trajectories labelled. The leading natural hypothesis for this unexpected deviation is internal gas jets becoming active on the Sun-warmed asteroid -- but speculation and further computer simulations are ongoing. 'Oumuamua will never return, but modern sky monitors are expected to find and track similar interstellar asteroids within the next few years.