Looking east from her house in Puerto Peñasco, Mexico, Jean Riddiough (Member 45,365) could see the launch of SpaceX’s Falcon 9 rocket from the Vandenberg Space Force Base in southern California, US. As the rocket passed through the mesosphere, 30 to 50 miles (50 to 85 km) above the Earth’s surface, it left a trail of ice crystals. Though the lower layers of the atmosphere were in Earth’s shadow, sunlight could still reach these higher layers, which is why this rocket trail shines even as the rest of the sky appears dark. We refer to such high-altitude clouds that shine at night like this as noctilucent clouds – although these were manmade, rather than natural, ones. Jean compared them to a celestial stingray ‘rising up to streak over the ocean’.