In Images: The Amazing Discovery of a Neutron-Star Crash, Gravitational Waves & More

This illustration depicts the merger of two neutron stars. The rippling spacetime grid represents gravitational waves that travel out from the collision, while the narrow beams show the burst of gamma rays launched just seconds after the gravitational waves. Swirling clouds of material ejected from the merging stars glow with visible and other wavelengths of light.

On Aug. 17, 2017, the Laser Interferometer Gravitational-Wave Observatory detected gravitational waves from a neutron star collision. Observatories identified the source of the event in the galaxy NGC 4993 and located the associated stellar flare known as a “kilonova.” Hubble watched that flare of light fade over the course of 6 days, as shown in these images from the space telescope.

The galaxy NGC 4993, where two neutron stars collided, is located about 130 million light-years from Earth. The event also resulted in a flare of light called a kilonova, which is visible to the upper left of the galactic center in this Hubble Space Telescope image.

1) A pair of neutron stars orbiting one another in a binary system spiral together. Orbital momentum dissipates through the release of gravitational waves. 2) In the final milliseconds, the two objects merge and produce a gamma-ray burst lasting just a fraction of a second. 3) A fraction of the mass of the merging neutron stars is flung out during the merger. This hot, radioactive material expands and emits infrared light. The explosion is about 1,000 times brighter than a classical nova and is called a “kilo nova.” 4) A massive neutron star or black hole remains after the event surrounded by an expanding cloud of debris.

This illustration shows the expanding cloud of debris stripped from two neutron stars just before they collided. This neutron-rich debris forged some of the universe’s heaviest elements, like gold and platinum.

Right: An image taken on Aug. 17, 2017, with the Swope Telescope at the Las Campanas Observatory in Chile shows the light source generated by a neutron-star merger in the galaxy NGC 4993. Left: In this photo taken on April 28, 2017, with the Hubble Space Telescope, the neutron star merger has not occurred and the light source, known as SSS17a, is not visible.

Swope and Magellan telescope optical and near-infrared images of the first optical counterpart to a gravitational-wave source, SSS17a, in its galaxy, NGC 4993. The left image is from August 17, 2017, 11 hours after the LIGO-Virgo detection of the gravitational-wave source, and contains the first optical photons from the source. The right image is from four days later, when SSS17a—the aftermath of a neutron star merger—faded significantly and its color became much redder.

This image from the MUSE instrument on ESO’s Very Large Telescope at the Paranal Observatory in Chile shows the galaxy NGC 4993, about 130 million light-years from Earth. The aftermath of the explosion of a pair of merging neutron stars, a rare event called a kilonova can be seen just above and slightly to the left of the center of the galaxy.

The image on the left shows the kilonova (just above and to the left of the brightest galaxy) recorded by the Dark Energy Camera. The image on the right was taken several days later and shows that the kilonova has faded.

The LIGO project operates two detector sites: one near Hanford in eastern Washington, and another near Livingston, Louisiana (shown here).

This is CSIRO’s Australia Telescope Compact Array, used by the Sydney team to detect gravitational waves.

University of Sydney Associate Professor and Chief Investigator at the ARC Centre of Excellence for All-sky Astrophysics (CAASTRO) Tara Murphy stands with PhD student Dougal Dobie (right) and astronomer Christene Lynch (left). Mr Dobie spent hours observing on the telescope and was amazed to be able to be the first in the world to observe the phenomenon.

This visualization shows the coalescence of two orbiting neutron stars. The right panel contains a visualization of the matter of the neutron stars. The left panel shows how spacetime is distorted near the collisions.

On Aug. 17, 2017, detectors spotted gravitational waves produced by the collision of two neutron stars (shown in this artist’s impression). The scientists also observed a gamma-ray burst from the energetic event.

This map shows the locations of all five gravitational-wave signals detected by LIGO since the first detection in 2015. In the background is an optical image of the Milky Way; the discoveries are plotted on the entire celestial sphere, which is represented as a translucent dome.

This artist’s illustration shows two neutron stars (bright blue dots in the middle of the image) merging together and creating jets of matter and light. The event was first seen by gravitational wave observatories, and was later studied by light-based observatories.

Artist’s impression of the GW170817 kilonova.

This numerical simulation depicts two inspiraling and merging neutron stars, highlighting the gravitational waves emitted during the merger.

A numerical simulation depicts two merging neutron stars, highlighting their density distribution. Higher density (the interior of the neutron stars) is shown in blue, while lower density (crust of the neutron stars) is shown in red.

This is an artist’s rendition of colliding neutron stars creating gravitational waves and a kilonova.

An artists’ rendition of two neutron stars merging. In the top panel, two stars are starting to spiral together while emitting gravitational waves. In the bottom panel, the collision has occurred and the system is emitting electromagnetic radiation.