Introduction
The concept of gravitational waves is a longstanding idea. Albert Einstein briefly covered it when he explained that ripples of space-time known as gravitational waves occur when large bodies orbit each other. He made these predictions in the development of the general theory of relativity in 1916. The calculations associated with the idea revealed that huge bodies such as black holes and neutron stars encircling each other at high speeds would cause ripples that would move outward from the source in all directions. Einstein added that the undulations would travel at the speed of light. This concept has been studied for many years and none of the experiments conducted has provided conclusive results to validate the claims, until five years ago. On 14 September 2015, the first successful direct observation of gravitational waves was recorded by the Laser Interferometer Gravitational-Wave Observatory (LIGO) in Louisiana and Washington.
Background of Gravitational Waves
Scientists have researched gravitational waves for many decades since Einstein predicted their existence in his 1916 theory of relativity. His calculations regarding the bending of light by the sunset the stage for further studies that validated his theory. A 1916 paper argued that if space were like a trampoline that can warp and curve, tapping it would cause undulations that would be “ripples in the fabric of space,” thus explaining the concept of gravitational waves (“Gravitational Waves,” 00:06:00-00:07:55). The calculations included in the paper were erroneous, but Einstein corrected them in 1918. Other scientists developed a systematic framework that authenticated the claim that gravitational waves were a real phenomenon. In the video titled “Gravitational Waves: A New Era of Astronomy Begins,” the LIGO team explains that the waves stretch and squeeze space. However, they are so small in magnitude that it is difficult to detect them. This problem was solved by scientists involved in the project: Rai Weiss, Barry Barish, Nergis Mavalvala, Frans Pretorius, and David Shoemaker. In the video, they discuss the concept of gravitational waves, the journey to discovery, and what the future holds for the field of astronomy.
One of the foremost scientists to study the phenomenon was Joe Webber, who conducted an experiment and claimed to have observed gravitational waves. However, his results were doubted by many who distanced themselves from his research. Weber was unrelenting and held on to his findings. Scientists were very skeptical of the possibility of observing the waves. An IBM physicist, Richard Garwin, conducted similar experiments to evaluate Weber’s claims; his detector caught a single pulse, which was attributed to noise. Studies continued until a breakthrough was attained by LIGO in 2015.
Discovery
The LIGO team was skeptical of the results after observing the waves and attributed them to an accidental or intentional process within the project. In the fall of 2015, rumors spread before the issuance of an official announcement that the team had discovered gravitational waves. They were apprehensive because they had not confirmed that the signal was a gravitational wave and not the result of an injected signal. Moreover, the detection apparatus was in the testing phase.
Weiss explains that the event had occurred 1.3 billion years ago, and it involved the collision of two black holes that caused waves that rippled through space (“Gravitational Waves, ” 00:19:40-00:20:20). The observatory detected the signal as it passed through planet Earth. The scientists explain that the discovery was coincidental because the wave appeared at a time when the observatory was in the testing phase. The detection was also made possible by the contribution of Pretorius, who has been studying black holes for more than two decades. One of the challenges they faced was the fear of sabotage as the results had to be similar in both the Washington and Louisiana stations. A previous experiment conducted at the South Pole by BICEP2 had reported the discovery of gravitational waves. However, further probes revealed that the undulations had been caused by Galactic dust (“Gravitational Waves,” 00:22:34-00:25:15). Prior experiments had been worse and the group had made significant improvements to the technology used. However, their results were wrong because of using insufficient detectors and a lack of peer review.
Frans was responsible for the numerical aspect of the discovery and provided solutions to the field equations of Einstein’s theory of relativity. The first answer to the equations was provided in 1915 by Carl Schwarzschild, and it turned out to be the first black hole solution (“Gravitational Waves,” 00:32:10-00:35:25). In 1963, Roy Kerr developed an explanation for calculations involving rotating black holes. Colliding black holes lack symmetry. Therefore, scientists took several years to compute answers to related field equations. The development of computing led to a breakthrough that resulted in the 2015 discovery by LIGO. It has been hailed as a historical event in the history of modern science because a gravitational wave is the most energetic astrophysical object observed since the big bang.
The Future
The detection of gravitational waves was a breakthrough in the field of astronomy because of its numerous possible applications. First, the waves could be used in studies to provide more insights into the nature of gravity (“Gravitational Waves,” 1:27:20-:1:29:30). Einstein’s theory was general and did not provide a deep understanding of the natural force. Second, it could be useful in the study of the universe. Gravitational waves are the only radiation form that can travel through very hot and compact materials without distortion (“Gravitational Waves,” 1:25:10-1:25:28). In that regard, it could be applied in the observation of the Big Bang theory that is credited with the origin of the universe. Third, gravitational waves could be used to solve string theory and introduce a concept that is not part of Einstein’s theory of relativity (“Gravitational Waves,” 1:25:40-1:26:37). The scientists’ main goal is to develop advanced instruments in order to increase the sensitivity and accuracy of their detections. For example, more advanced interferometers could be used to observe all the black holes in the universe. Numerically, the inclusion of neutron stars in the studies might enhance the detection of gravitational waves.
Conclusion
In the past century, one of the groundbreaking scientific discoveries was the detection of gravitational waves. For many decades, scientists were unsure of their existence. However, Einstein’s theory of general relativity provided an impetus for scientists to conduct experiments to find them in the universe. Weber’s experiments were invalidated because further studies revealed that the undulations that he had claimed to observe were pulses from noise. The scientific community through the LIGO team confirmed the existence of black holes in 2015 when they observed successfully a gravitational wave that had been caused by a collision of two black holes about 1.3 billion years ago. The video provides insights into the concept first alluded to by Einstein.
Work Cited
“Gravitational Waves: A New Era of Astronomy Begins.” YouTube, 2016. Web.