Two-photon interference shows promise as a method for one day detecting the ripples in space-time caused by the most violent events in the universe.
When a pair of black holes collide, they typically merge, but sometimes one of them may be kicked in the opposite direction at great speed.
By setting up competitions, NASA hopes to attract "citizen inventors" from diverse backgrounds to develop 3D-printing technologies for space exploration.
Before NASA's Cassini probe burns up in Saturn's atmosphere on September 15, it is diving between the planet's rings, which scientists say could yield stunning discoveries.
The spacecraft's last act will be a data-harvesting dive that collects the most detailed observations ever obtained of Saturn's atmosphere and ring material.