LIGO Scientific Collaboration and Virgo Collaboration Archives

August 30, 2023August 30, 2023 by Brian Koberlein

It's Time for a Gravitational Wave Observatory in the Southern Hemisphere

Map of current and planned gravitational wave observatories. Credit: Caltech/MIT/LIGO Lab

What’s true for optical astronomy is also true for gravitational wave astronomy: the more observatories you have, the better your view of the sky. This is why the list of active gravitational wave observatories is growing. But so far they are all in the Northern Hemisphere. As a recent article on the arXiv points out, that means we are missing out on a good number of gravitational events.

May 24, 2023May 24, 2023 by Nancy Atkinson

After Three Years of Upgrades, LIGO is Fully Operational Again

The Laser Interferometer Gravitational-Wave Observatory is made up of two detectors, this one in Livingston, La., and one near Hanford, Wash. The detectors use giant arms in the shape of an "L" to measure tiny ripples in the fabric of the universe. Credit: Caltech/MIT/LIGO Lab

Have you noticed a lack of gravitational wave announcements the past couple of years? Well, now it is time to get ready for an onslaught, as the Laser Interferometric Gravitational-Wave Observatory (LIGO) starts a new 20-month observation run today, May 24^thafter a 3-year hiatus.

LIGO has been offline for the last three years, getting some serious new upgrades. One upgrade, called “quantum squeezing,” reduces detector noise to improve its ability to sense gravitational waves.

Astronomers expect this upgrade could double the sensitivity of LIGO. This will allow black hole mergers to be seen more clearly, and it could also allow LIGO to see mergers that are fainter or farther away. Or, perhaps it could even detect new kinds of mergers that have never been seen before.

January 5, 2023January 8, 2023 by Laurence Tognetti

What Does it Take to Make Black Holes Collide?

Simulation of the emitted light from a supermassive black hole binary system. (Credit: NASA’s Goddard Space Flight Center)

In a recent study published in Astronomy and Astrophysical Letters, a team of researchers at the Massachusetts Institute of Technology (MIT) used various computer models to examine 69 confirmed binary black holes to help determine their origin, and found their data results changed based on the model’s configurations, and the researchers wish to better understand both how and why this occurs and what steps can be taken to have more consistent results.

August 24, 2022August 24, 2022 by Brian Koberlein

Colliding Black Holes Provide Another way to Measure Distance in the Universe

A simulation of two merging black holes. Credit: Simulating eXtreme Spacetimes (SXS) Project

We know the universe is expanding, and we have a pretty good idea of how fast it’s expanding, but we don’t know the rate exactly. That’s because of the different methods we have to measure the rate of cosmic expansion keep giving us slightly different results. It’s a nagging problem that bugs astronomers, so while they have worked to ensure current methods are accurate, they have also looked to new ways to measure cosmic expansion. One of these new ways involves gravitational waves.

August 22, 2022August 22, 2022 by Brian Koberlein

Gravitational Waves Will Give Astronomers a new way to Look Inside Neutron Stars

Illustration showing the merger of two neutron stars. Credit: NASA's Goddard Space Flight Center/CI Lab

It’s difficult to study neutron stars. They are light years away and only about 20 kilometers across. They are also made of the most dense material in the universe. So dense that atomic nuclei merge together to become a complex fluid. For years our understanding of the interiors was based on complex physical models and what little data we could gather from optical telescopes. But that’s starting to change.

July 25, 2021July 25, 2021 by Brian Koberlein

A Gravitational Wave Observatory on the Moon Could "Hear" 70% of the Observable Universe

Concept for a Gravitational-wave Lunar Observatory for Cosmology (GLOC). Credit: Jani, et al

Gravitational-wave astronomy is set to revolutionize our understanding of the cosmos. In only a few years it has significantly enhanced our understanding of black holes, but it is still a scientific field in its youth. That means there are still serious limitations to what can be observed.

July 1, 2021July 1, 2021 by Brian Koberlein

Astronomers Detected a Black Hole-Neutron Star Merger, and Then Another Just 10 Days Later

An artistic image inspired by a black hole-neutron star merger event. Credit: Carl Knox, OzGrav/Swinburne

The interior of a neutron star is perhaps the strangest state of matter in the universe. The material is squeezed so tightly that atoms collapse into a sea of nuclear material. We still aren’t sure whether nucleons maintain their integrity in this state, or whether they dissolve into quark matter. To really understand neutron star matter we need to pull it apart to see how it works and to do that takes a black hole. This is why astronomers are excited about the recent discovery of not one, but two mergers between a neutron star and a black hole.

January 14, 2021January 14, 2021 by Brian Koberlein

Astronomers see a Hint of the Gravitational Wave Background to the Universe

Artist view of orbiting black holes. Credit: Caltech/R. Hurt (IPAC)

Gravitational-wave astronomy is still in its infancy. LIGO and other observatories have opened a new window on the universe, but their gravitational view of the cosmos is limited. To widen our view, we have the North American Nanohertz Observatory for Gravitational Waves (NANOGrav).

December 16, 2020December 16, 2020 by Brian Koberlein

Next Generation Gravitational Wave Detectors Should be Able to see the Primordial Waves From the Big Bang

An artist view of primordial gravitational waves. Credit: Carl Knox, OzGrav/Swinburne University of Technology

Gravitational-wave astronomy is still in its youth. Because of this, the gravitational waves we can observe come from powerful cataclysmic events. Black holes consuming each other in a violent chirp of spacetime, or neutron stars colliding in a tremendous explosion. Soon we might be able to observe the gravitational waves of supernovae, or supermassive black holes merging billions of light-years away. But underneath the cacophony is a very different gravitational wave. But if we can detect them, they will help us solve one of the deepest cosmological mysteries.

November 17, 2020November 17, 2020 by Evan Gough

Merging Black Holes and Neutron Stars. All the Gravitational Wave Events Seen So Far in One Picture

The mergers of compact objects discovered so far by LIGO and Virgo (in O1, O2 and O3a). The diagram shows black holes (blue), neutron stars (orange) and compact objects of unknown nature (grey), which were detected by their gravitational-wave emission. Each merger of a binary system corresponds to three compact objects shown: the two merging objects and the result of the merger. A selection of black holes (violet) and neutron stars (yellow) discovered by electromagnetic observations is shown for comparison. Image Credit: LIGO Virgo Collaboration / Frank Elavsky, Aaron Geller / Northwestern

The Theory of Relativity predicted the existence of black holes and neutron stars. Einstein gets the credit for the theory because of his paper published in 1915, even though other scientists’ work helped it along. But regardless of the minds behind it, the theory predicted black holes, neutron stars, and the gravitational waves from their mergers.

It took about one hundred years, but scientists finally observed these mergers and their gravitational waves in 2015. Since then, the LIGO/Virgo collaboration has detected many of them. The collaboration has released a new catalogue of discoveries, along with a new infographic. The new infographic displays the black holes, neutron stars, mergers, and the other uncertain compact objects behind some of them.