Europe is building a gravitational wave telescope with arms millions of kilometers long

The Laser Interferometer Space Antenna, or LISA, is a trio of spacecraft designed to function as a single, massive telescope in deep space. By operating at lower frequencies than existing detectors, this mission promises to reveal black hole mergers months before they occur.

LISA functions by using free-flying gold cubes as reference masses within each of its three spacecraft. Maintaining these cubes in a state of perfect free fall is essential for the telescope's precision. To ensure this technology would perform as required, the LISA Pathfinder mission was launched to test the necessary control systems in space.

The mission's vast scale allows it to observe phenomena involving supermassive black holes that are otherwise undetectable. By monitoring gravitational waves at these lower frequencies, scientists expect to capture data on events long before they reach their peak, offering a new window into the dynamics of the universe.

Source: How To Build A Million Mile Wide Telescope- Europe's Groundbreaking LISA Mission