Author: Megan Loh
In the 21st century, scientific discovery and innovation surround us. Humanity pushes to explore the undiscovered, but what lies outside of our galaxy today still remains largely unknown. The Laser Interferometer Gravitational-Wave Observatory, otherwise known as LIGO, has been working to change that.
When you look up at the sky at night, you see an empty canvas splashed with white specks of brilliant, shining stars. There’s so much more in the darkness than just stars that the human eye, even the strongest telescopes, can see. This can be for two reasons: the body is too far away, or it does not let light escape from it—a black hole. What cannot be seen is black hole collisions, or a binary black hole system merging. One way to detect these spacetime anomalies is to use gravitational waves. LIGO’s main objective is to detect gravitational waves from outer space and use that data to discern irregularities in the data.
Advanced LIGO has run two observational runs as of March 2019, O1 and O2, and in those runs, they have detected a total of ten black hole mergers. This is an incredible scientific breakthrough for the astronomy community, as this could lead to many more implications and future studies on how the black holes actually merge, and what happens after they merge. Nobel laureate George Smoot argues that at least one of the mergers detected could actually be a gravitationally lensed black hole merger, which implies that the black hole collision occurred while there was a galaxy blocking the direct path to Earth. Galaxies effectively act as a spacetime lens for distant space objects, curving spacetime in order to magnify the light received by Earth. If Smoot’s hypothesis is true, the gravitational wave results could be a revolutionary discovery for the scientific community. If the detected black hole mergers were lensed events, they would be from the early universe, which would give scientists insight on the evolution of stars and black holes throughout time. The results of the O2 observational run were recently published by LIGO, the largest data set from advanced gravitational wave detectors to date. Scientists in the field will be able to use this data for additional scientific investigations to uncover more information about how black holes emit gravitational waves as they merge, and will be able to program a more accurate model of the merging of two black holes. The information that these studies provide are the key to unlocking the secrets of the universe, and discovering the undiscovered.
LIGO’s third observational run, O3, is set to start on April 1st of this year, and will run for one calendar year. For the upcoming run, they are currently running Engineering Run 14 to test equipment and make sure they are functional. Their sensitivity is 20-30% better than O2, with the best interferometer consistently running at 130 Megaparsecs. The two major improvements for O3 are optical squeezing, to lower the amount of noise detected, and increased laser power. Additionally, scientists have learned how to discharge the mirrors in the interferometer mid-run without breaking the vacuum seal, which will further eliminate noise and error. All of these improvements promise to bring a year full of scientific discoveries and breakthroughs in astronomy as LIGO searches for answers within our universe.
When I ask my peers if they have heard about LIGO, almost all perk up and respond, “Yes, of course I have!” But when I ask them if they know what LIGO stands for, what it does, or even if they know about any recent discoveries, they’re stuck. There are countless young minds waiting to learn about and even contribute to these studies, but they don’t have enough exposure to the topic. I think it’s incredibly important to educate others on the implications of LIGO’s research and how it works, in order to engage them and expand the community.
Black holes piqued my interest in middle school, particularly how they sink through the fabric of spacetime and don’t let light escape. In my eyes, they defied the laws of what defined the world around me. This particular topic riveted my attention when I joined the Gravitational-Wave Physics and Astronomy Center at my local university. Under the direction of Professor Read, I expanded my knowledge on the manipulation of black holes and black hole anomalies, and my fascination grew exponentially. How I define science is the exploration of the world around us and the explanation for how the world works. The implications of these studies, being at the frontier of scientific and extraterrestrial discovery, give so much meaning to science for me. These scientific studies bring us one step closer to understanding what surrounds us and taking the reigns of technological innovation.
One of the major highlights of the O3 run so far is the first picture of a real black hole!