A final test of relativity

A European Space Agency probe will be launched into space early next month to help test the last major prediction of Einstein’s theory of general relativity: the existence of gravitational waves.

Gravitational waves are thought to be hurled across space when stars start throwing their weight around, for example, when they collapse into black holes or when pairs of super-dense neutron stars start to spin closer and closer to each other. These processes put massive strains on the fabric of space-time, pushing and stretching it so that ripples of gravitational energy radiate across the universe. These are gravitational waves.

The Lisa Pathfinder probe won’t measure gravitational waves directly, but will test equipment that will be used for the final detector.

LISA Pathfinder will pave the way for future missions by testing in flight the very concept of gravitational wave detection: it will put two test masses in a near-perfect gravitational free-fall and control and measure their motion with unprecedented accuracy. LISA Pathfinder will use the latest technology to minimise the extra forces on the test masses, and to take measurements. The inertial sensors, the laser metrology system, the drag-free control system and an ultra-precise micro-propulsion system make this a highly unusual mission.

(via @daveg)

• Albert Einstein
• ESA
• gravity
• physics
• science
• space