At http://phys.org/print362930969.html … the New Horizons spacecraft has returned pictures of Charon, the larger companion of Pluto. The pictures are thought to show a very violent history, possibly even evidence of a collision. The solar system is becoming more insecure the more it is investigated.
It is covered with mountains, canyons, fractures, craters, landslides and surface colour variations. One canyon system stretches for over a thousand miles and is four times the size of the Grand Canyon and twice the depth. Faults and rifts indicate geological upheaval. One spokesman is quoted as saying it looked like Charon has been split open.The story source is www.nasa.gov/feature/pluto-s-big-moon-charon-reveals-a-clorful-and-viole… … and the link provides more images to peruse. One can't help but think worlds in collision is no longer far fetched.