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 24th after 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.
With greater sensitivity, astronomers will be able to trace GW events back to their source and use them to probe the interiors of exotic objects and the laws of physics. As part of their Voyage 2050 planning cycle, the European Space Agency (ESA) is considering mission themes that could be ready by 2050 – including GW astronomy. In a recent paper, researchers from the ESA’s Mission Analysis Section and the University of Glasgow presented a new concept that would build on LISA – known as LISAmax. As they report, this observatory could potentially improve GW sensitivity by two orders of magnitude.
Fast Radio Bursts (FRBs) were first detected in 2007 (the Lorimer Burst) and have remained one of the most mysterious astronomical phenomena ever since. These bright radio pulses generally last a few milliseconds and are never heard from again (except in the rare case of Repeating FRBs). And then you have Gravitational Waves (GW), a phenomenon predicted by General Relativity that was first detected on September 14th, 2015. Together, these two phenomena have led to a revolution in astronomy where events are detected regularly and provide fresh insight into other cosmic mysteries.
In a new study led by the Australian Research Council Centre of Excellence for Gravitational Wave Discovery (OzGrav), an Australian-American team of researchers has revealed that FRBs and GWs may be connected. According to their study, which recently appeared in the journal Nature Astronomy, the team noted a potential coincidence between a binary neutron star merger and a bright non-repeating FRB. If confirmed, their results could confirm what astronomers have expected for some time – that FRBs are caused by a variety of astronomical events.
According to new research led by the Advanced Propulsion Laboratory at Applied Physics (APL-AP), GWs could also be used in the Search for Extraterrestrial Intelligence (SETI). As they state in their paper, LIGO and other observatories (like Virgo and KAGRA) have the potential to look for GWs created by Rapid And/or Massive Accelerating spacecraft (RAMAcraft). By combining the power of these and next-generation observatories, we could create a RAMAcraft Detection And Ranging (RAMADAR) system that could probe all the stars in the Milky Way (100 to 200 billion) for signs of warp-drive-like signatures.
In a recent study, an international team of researchers led by Cardiff University observed a binary black hole system originally detected in 2020 by the Advanced LIGO, Virgo, and Kamioki Gravitational Wave Observatory (KAGRA). In the process, the team noticed a peculiar twisting motion (aka. a precession) in the orbits of the two colliding black holes that was 10 billion times faster than what was noted with other precessing objects. This is the first time a precession has been observed with binary black holes, which confirms yet another phenomenon predicted by General Relativity (GR).
Gamma rays could be the new source for observing gravitational waves, according to a recent release from the Max Planck Institute for Radio Astronomy. This would make a possible third way to observe gravitational waves including laser interferometry and radio waves.
In 1916 Einstein predicted the existence of gravitational waves, ripples in space-time moving out in all directions away from massive accelerating objects. According to his theory, these waves would travel at the speed of light and would carry with them information about where they came from and would allow us to learn more about gravity.
In February 2016, scientists with the Laser Interferometer Gravitational-Wave Observatory (LIGO) confirmed the first-ever detection of a gravitational wave event. Originally predicted by Einstein’s Theory of General Relativity, GWs result from mergers between massive objects – like black holes, neutron stars, and supermassive black holes (SMBHs). Since 2016, dozens of events have been confirmed, opening a new window to the Universe and leading to a revolution in astronomy and cosmology.
In another first, a team of scientists led by the Center for Computational Relativity and Gravitation (CCRG) announced that they may have detected a merger of two black holes with eccentric orbits for the first time. According to the team’s paper, which recently appeared in Nature Astronomy, this potential discovery could explain why some of the black hole mergers detected by the LIGO Scientific Collaboration and the Virgo Collaboration are much heavier than previously expected.
The confirmation of gravitational waves back in 2017 continues to unlock whole new worlds of physics but also continues to elicit further questions. The detection of each gravitational wave brings a new challenge – how to find out what caused the event. Sometimes that is harder than it sounds. Now a team led by Alejandro Vigna-Gomez of the University of Copenhagen thinks they found a model of star death that helps to explain some previously inexplicable findings – and points to a galaxy with many more massive neutron stars than previously thought.
Materials science has once again come through for space exploration. Researchers at the Laser Interferometer Gravitational-Wave Observatory (LIGO) have developed a coating that could increase the sensitivity of LIGO by almost an order of magnitude. That would increase the detection rate of the gravitational waves the observatory is seeking from about once a week to once a day, mainly due to the increased volume of space that the observatory’s interferometers would be able to collect signals from.
Gravitational-wave astronomy is very different from that of electromagnetic light. While gravitational waves are faint and difficult to detect, they also pass through matter with little effect. In essence, the material universe is transparent to gravitational waves. This makes gravitational wave astronomy a powerful tool when studying the universe. But it’s still in the early stages, and there is much to learn about how gravitational waves behave.