An Air Force Test Pilot School T-38C passes in front of the sun at a supersonic speed, creating shockwaves that are caught photographically for research. NASA is using a modern version of schlieren imagery to visualize supersonic flow phenomena with full-scale aircraft in flight. The results will help engineers design a quiet supersonic transport.
It's difficult to get a sense of scale when viewing Saturn's rings, but the Cassini Division (seen here between the bright B ring and dimmer A ring) is almost as wide as the planet Mercury.
Expedition 47 Flight Engineer Tim Peake of ESA took this photograph on April 6, 2016, as the International Space Station flew over Madagascar, showing three of the five spacecraft docked to the station. The station crew awaits the scheduled launch today, April 8, of the third resupply vehicle in three weeks: a SpaceX Dragon cargo spacecraft.
Twenty-five years ago, NASA launched the Compton Gamma Ray Observatory, an astronomical satellite that transformed our knowledge of the high-energy sky. In this view, taken on April 7, 1991, from the aft flight deck window of space shuttle Atlantis, the Compton Gamma Ray Observatory is released by the shuttle's remote manipulator system.