Listen up

Gravitational waves help us listen to the cosmos

Scientists have been listening in to these ripples in space-time for five years.

by Passant Rabie

Caltech

On September 14, 2015, scientists detected the first gravitational waves using the Laser Interferometer Gravitational-Wave Observatory (LIGO). The waves were ripples in space-time created by two colliding black holes, 1.3 billion years ago.

NASA

100 years earlier, Einstein's Theory of General Relativity predicted the existence of gravitational waves. The theory stated that when objects accelerate through space, they create ripples in space-time around them that move at the speed of light.

Powerful gravitational waves result from some of the most violent events in the cosmos, such as the merger of two black holes, colliding neutron stars, or explosive supernovae.

Henze/NASA

By the time they reach Earth, the gravitational waves are relatively weak and last for mere seconds. Scientists can analyze these signals to discover their origins, and uncover clues about the early universe.

NSF/LIGO

One of the signals detected is believed to have been the result of a first-of-its-kind merger between a neutron star and a black hole.

In September, astronomers detailed a gravitational wave signal that had traveled across 7 billion lightyears to reach Earth. The signal may have been caused by the most massive collision of two black holes ever detected, creating an intermediate mass black hole.

"With electromagnetic radiation, light, we can see the universe but with gravitational waves, we can hear the universe."

Nelson Christensen, a researcher at the French National Centre for Scientific Research

N. Fischer, S. Ossokine, H. Pfeiffer, A. Buonanno (Max Planck Institute for Gravitational Physics), Simulating eXtreme Spacetimes (SXS) Collaboration.

Gravitational wave signals let astronomers are 'see' the invisible side of the universe.

Read more about gravitational waves here.

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