Space & Innovation

Spacetime Ripples: When Black Holes Collide

The detection of gravitational waves has opened our eyes to a previously unexplored dimension of the universe -- browse this gallery to see how gravitational wave astronomy will change our view of the cosmos.

On Dec. 26, 2015, the entire planet experienced a spacetime disturbance in the form of gravitational waves. These waves are far too slight to affect our everyday lives, but their detection marks a revolution in physics. Scientists of the Laser Interferometer Gravitational-wave Observatory, or LIGO, had already discovered gravitational waves a few months earlier on Sept. 14, but detecting these waves for the second time confirmed it wasn't a fluke: we really do live in a universe awash with gravitational waves and we can use them to "see" a previously dark dimension of the cosmos, such as previously invisible black hole mergers.

Image: A graphical representation of two black holes rapidly spinning before merging as one. The spiral is gravitational waves being generated by this violent event. Credit: Caltech/MIT/LIGO

This animation shows the merger of two black holes and the gravitational waves rippling through spacetime. The two black holes shown here represent the 8 and 14 solar mass black holes detected by LIGO on Dec. 26, 2015. After the black holes collided and merged, they created one 21 solar mass black hole. One solar mass was converted into gravitational waves, carrying energy away from the event and detected by LIGO as a signal named GW151226.

Credit: LIGO/T. Pyle

The LIGO project consists of two identical sites, in Washington and Louisiana, located nearly 2,000 miles apart. Shown here is the Hanford Observatory in Washington State. Both detectors are highly sensitive interferometers that fire precision lasers down 2.5 mile-long tunnels. To detect the passage of gravitational waves, they are able to detect extremely slight warps in space, to a precision of 10,000 times smaller than the width of a proton. With the two stations, physicists are able to get a rough idea as to the direction of gravitational wave travel and therefore have an idea of where they came from.

Credit: LIGO

This graphic shows a general timeline of Advanced LIGO's first observing run from Sept. 12 to Jan. 19. Only 2 days after going online in 2015, the upgraded system made the first detection of gravitational waves generated by the collision of a 29 and 36 solar mass black hole -- a signal called GW150914. On Oct. 12 a candidate signal (LVT151012) emerged from the noise. Later in the observing run, on Dec. 26, GW151226 was detected and confirmed.

Credit: LIGO

This is what black hole mergers sound like. By converting the gravitational wave frequencies into sound, the rapidly-spinning and then merging black holes make a "chirp."

Credit: LIGO

"The approximate location of the gravitational-wave event detected on December 26, 2015 by LIGO is shown on this sky map of the southern hemisphere. The colored lines represent different probabilities for where the signal originated: the outer purple line defines the regionwhere the signal is predicted to have come from with a 90 percent confidence level; the inneryellow line defines the target region at a 10 percent confidence level."

Image/caption credit: LIGO/Axel Mellinger

"The approximate locations of the two gravitational-wave events detected so far by LIGO are shown on this sky map of the southern hemisphere. The colored lines represent different probabilities for where the signal originated: the outer purple line defines the region where the signal is predicted to have come from with a 90 percent confidence level; the inner yellow line defines the target region at a 10 percent confidence level."

Image/caption credit: LIGO/Axel Mellinger

This handy chart compares the LIGO black hole mergers with black holes detected from their X-ray emissions.

Credit: LIGO