Gravitational Waves Archives

April 22, 2020April 22, 2020 by Matt Williams

Astronomers Detected a Black Hole Merger With Very Different Mass Objects

Still image from a numerical simulation of an unequal mass binary black hole merger, with parameters consistent with GW190412. [Image credit: N. Fischer, H. Pfeiffer, A. Buonanno (Max Planck Institute for Gravitational Physics), Simulating eXtreme Spacetimes project]

In another first, scientists at the LIGO and Virgo gravitational wave detectors announced a signal unlike anything they’ve ever seen before. While many black hole mergers have been detected thanks to LIGO and Virgo’s international network for detectors, this particular signal (GW190412) was the first where the two black holes had distinctly different masses.

March 11, 2020March 11, 2020 by Nancy Atkinson

Neutron Star Measures Just 22 Kilometers Across

A typical neutron star with a radius of eleven kilometres is about as large as a medium-sized city. Credit: NASA's Goddard Space Flight Center

How big is a neutron star? These extreme, ultra-dense collapsed stars are fairly small, as far as stellar objects are concerned. Even though they pack the mass of a full-sized star, their size is often compared to the width of a medium-to-large-sized city. For years, astronomers have pegged neutron stars at somewhere between 19-27 km (12 to 17 miles) across. This is quite actually quite precise, given the distances and characteristics of neutrons stars. But astronomers have been working to narrow that down to an even more precise measurement.

An international team of researchers has now done just that. Using data from several different telescopes and observatories, members of the Max Planck Institute for Gravitational Physics, theAlbert Einstein Institute (AEI) have narrowed the size estimates for neutron stars by a factor of two.

February 5, 2020February 5, 2020 by Evan Gough

14% of all the Massive Stars in the Universe are Destined to Collide as Black Holes

This illustration shows the merger of two black holes and the gravitational waves that ripple outward as the black holes spiral toward each other. Could black holes like these (which represent those detected by LIGO on Dec. 26, 2015) collide in the dusty disk around a quasar's supermassive black hole explain gravitational waves, too? Credit: LIGO/T. Pyle

Einstein’s Theory of General Relativity predicted that black holes would form and eventually collide. It also predicted the creation of gravitational waves from the collision. But how often does this happen, and can we calculate how many stars this will happen to?

A new study from a physicist at Vanderbilt University sought to answer these questions.

January 17, 2020January 17, 2020 by Evan Gough

A Mysterious Burst of Gravitational Waves Came From a Region Near Betelgeuse. But There’s Probably No Connection

Betelgeuse was the first star directly imaged -- besides our own Sun, of course. Image obtained by the Hubble Space Telescope. Credit: Andrea Dupree (Harvard-Smithsonian CfA), Ronald Gilliland (STScI), NASA and ESA

Gravitational waves are caused by calamitous events in the Universe. Neutron stars that finally merge after circling each other for a long time can create them, and so can two black holes that collide with each other. But sometimes there’s a burst of gravitational waves that doesn’t have a clear cause.

December 5, 2019December 5, 2019 by Brian Koberlein

LIGO Will Squeeze Light To Overcome The Quantum Noise Of Empty Space

The LIGO Hanford Observatory in Washington State. Credit: LIGO Observatory

When two black holes merge, they release a tremendous amount of energy. When LIGO detected the first black hole merger in 2015, we found that three solar masses worth of energy was released as gravitational waves. But gravitational waves don’t interact strongly with matter. The effects of gravitational waves are so small that you’d need to be extremely close to a merger to feel them. So how can we possibly observe the gravitational waves of merging black holes across millions of light-years?

September 11, 2019September 11, 2019 by Evan Gough

Hubble Has Looked at the 2017 Kilonova Explosion Almost a Dozen Times, Watching it Slowly Fade Away

An artistic rendering of two neutron stars merging. Credit: NSF/LIGO/Sonoma State/A. Simonnet

In 2017, LIGO (Laser-Interferometer Gravitational Wave Observatory) and Virgo detected gravitational waves coming from the merger of two neutron stars. They named that signal GW170817. Two seconds after detecting it, NASA’s Fermi satellite detected a gamma ray burst (GRB) that was named GRB170817A. Within minutes, telescopes and observatories around the world honed in on the event.

The Hubble Space Telescope played a role in this historic detection of two neutron stars merging. Starting in December 2017, Hubble detected the visible light from this merger, and in the next year and a half it turned its powerful mirror on the same location over 10 times. The result?

The deepest image of the afterglow of this event, and one chock-full of scientific detail.

September 9, 2019September 10, 2019 by Matt Williams

Gravitational Wave Detectors Might be Able to Detect Dark Matter Particles Colliding With Their Mirrors

The early universe. Credit: Tom Abel & Ralf Kaehler (KIPACSLAC)/ AMNH/NASA

The field of astronomy has been revolutionized thanks to the first-ever detection of gravitational waves (GWs). Since the initial detection was made in February of 2016 by scientists at the Laser Interferometer Gravitational-wave Observatory (LIGO), multiple events have been detected. These have provided insight into a phenomenon that was predicted over a century ago by Albert Einstein.

As it turns out, the infrastructure that is used to detect GWs could also help crack another astronomical mystery: Dark Matter! According to a new study by a team of Japanese researchers, laser interferometers could be used to look for Weakly-Interacting Massive Particles (WIMPs), a major candidate particle in the hunt for Dark Matter.

April 25, 2019April 27, 2019 by Matt Williams

As Expected, the Newly Upgraded LIGO is Finding a Black Hole Merger Every Week

In February 2016, LIGO detected gravity waves for the first time. As this artist's illustration depicts, the gravitational waves were created by merging black holes. The third detection just announced was also created when two black holes merged. Credit: LIGO/A. Simonnet. — Artist's impression of merging binary black holes. Credit: LIGO/A. Simonnet.

In February of 2016, scientists at the Laser Interferometer Gravitational-wave Observatory (LIGO) announced the first-ever detection of gravitational waves (GWs). Since then, multiple events have been detected, providing insight into a cosmic phenomena that was predicted over a century ago by Einstein’s Theory of General Relativity.

A little over a year ago, LIGO was taken offline so that upgrades could be made to its instruments, which would allow for detections to take place “weekly or even more often.” After completing the upgrades on April 1st, the observatory went back online and performed as expected, detecting two probable gravitational wave events in the space of two weeks.

April 24, 2019April 24, 2019 by Paul M. Sutter

Barfing Neutron Stars Reveal Their Inner Guts

Artist's illustration of two merging neutron stars. The narrow beams represent the gamma-ray burst while the rippling spacetime grid indicates the isotropic gravitational waves that characterize the merger. Swirling clouds of material ejected from the merging stars are a possible source of the light that was seen at lower energies. Credit: National Science Foundation/LIGO/Sonoma State University/A. Simonnet

We don’t really understand neutron stars. Oh, we know that they are – they’re the leftover remnants of some of the most massive stars in the universe – but revealing their inner workings is a little bit tricky, because the physics keeping them alive is only poorly understood.

But every once in a while two neutron stars smash together, and when they do they tend to blow up, spewing their quantum guts all over space. Depending on the internal structure and composition of the neutron stars, the “ejecta” (the polite scientific term for astronomical projectile vomit) will look different to us Earth-bound observers, giving us a gross but potentially powerful way to understand these exotic creatures.

March 20, 2019March 20, 2019 by Matt Williams

LIGO Just Got a Big Upgrade, Will Begin Searching for Gravitational Waves Again on April 1st

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

In February of 2016, scientists at the Laser Interferometer Gravitational-wave Observatory (LIGO) made history by announcing the first-ever detection of gravitational waves (GWs). These ripples in the very fabric of the Universe, which are caused by black hole mergers or white dwarfs colliding, were first predicted by Einstein’s Theory of General Relativity roughly a century ago.

About a year ago, LIGO’s two facilities were taken offline so its detectors could undergo a series of hardware upgrades. With these upgrades now complete, LIGO recently announced that the observatory will be going back online on April 1st. At that point, its scientists are expecting that its increased sensitivity will allow for “almost daily” detections to take place.