Scientists have directly observed gravitational waves, ripples in the fabric of spacetime, for the second time—confirming the start of a new era of astronomy.

Much like the historic first observation announced in February, the second event marked the cataclysmic embrace of two black holes more than a billion years ago. This fatal attraction sent shockwaves rippling across the universe, which astronomers recorded as they washed through Earth.

Produced by some of the universe’s most violent events—such as mergers of black holes and collisions of ultra-dense neutron stars—gravitational waves give scientists an entirely new way of observing the universe, potentially allowing them to measure and study things that are invisible in any wavelength of light.