The search for distant solar system objects has found two more small worlds far outside the orbit of Neptune, beyond the Kuiper Belt. The new objects, 2014 FZ71 and 2015 FJ345, are in resonance with Neptune’s orbit, implying that these worlds either have interacted with Neptune in the past or are continuing to do so.
In the race towards the discovery of Planet Nine, scientists from around the world strive to calculate its orbit using the tracks left by the small bodies that move well beyond Neptune. Now, astronomers from Spain and Cambridge University have confirmed that the orbits of the six extreme trans-Neptunian objects that served as a reference to announce the existence of Planet Nine are not as stable as originally thought.
Over the last two decades, the discovery of hundreds of giant comets, termed Centaurs, on unstable orbits in the outer planetary system means that these objects pose a much greater hazard to life than asteroids, according to a team of UK astronomers. Centaurs are typically 50 to 100 kilometres across, or larger, and a single such body contains more mass than the entire population of Earth-crossing asteroids found to date.