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Gravitational waves are variations of gravitational fields or ‘ripples in space-time fabric’ that are often the result of major energy emitting astral processes. Albert Einstein was the first scientist to predict the existence of gravitational waves through his groundbreaking theory of relativity. When major events involving massive astral bodies happen, the resulting distortions in space-time are often felt as a tidal wave by the objects that stand in its path.
The gravitational force “acts perpendicular to the waves’ direction of propagation; these forces change the distance between points, and the size of the changes is proportional to the distance between the points” (Cofield 1). The basic formation of gravitational waves starts from unexpected acceleration of massive objects such as neutron stars or black holes. Consequently, the acceleration has the effect of disrupting space-time thereby sending the distortion in the form of waves across the entire universe in the same way that throwing a rock in a body of water does. Gravitational waves often travel at the speed of light and that is how they reach distant places like our planet (Aasi 40).
The waves also carry vital information concerning their source among other previously unknown clues about the composition of gravity and the universe. Gravitational waves are quite strong at their point of origin but the fact that they travel over long distances means that they lose most of their strength before they reach the earth. Prior to 2015, there were no equipments that could detect gravitational waves until the Laser Interferometer Gravitational-Wave Observatory was completed in September of the same year.
Although there has always been evidence to show the existence of gravitational waves, actual proof of their existence only came in February 11 2016 when waves resulting from two merging black holes were detected. In future, the discovery of gravitational waves (GW) will assist scientists in learning more about their origins and also find out everyday applications for GW, as it is the case with electromagnetic waves. This essay focuses on the recent discovery of GW, the theory behind their institution, the infrastructure behind their detection, and their possible applications in the future.
It is expected that Newton’s theory of gravity would offer mainstream basis for explaining GW. For instance, the gravity theory as explained by Newton is used to explain how the universe works and how celestial bodies relate to each other. Nevertheless, GW is a product of the theory of general relativity as it was first proposed by Albert Einstein in 1916. There are key disparities between the laws of general relativity and gravity whereby “slowly moving bodies and weak gravitational fields reduce to the standard laws of Newtonian theory” (Cho 300).
The highlight of the general relativity theory is the fact that it introduces the concept of space-time to the existing notion of gravitational forces. Einstein was mainly concerned with what happens when there are drastic changes in a certain gravitational field and how these alterations are propagated. In the ‘old-fashioned’ concept of gravitational forces, a change in a gravity field is instant and it travels in an infinite speed.
The theory of relativity nullifies the concept GW’s infinite speed and introduces the notion of waves that result from a ripple in the fabric of space-time. The relative nature of gravity is responsible for the advent of the theory of general relativity. Nevertheless, the nature of GW aligns with the form and strength of gravity as outlined by Newton’s theory.
For quite a long period of time, general relativity has remained untested. The theory was first proposed in 1916 but the slightest proof of GW was only witnessed in 1974. The chance to proof this phenomenon came when “astronomers working at the Arecibo Radio Observatory in Puerto Rico discovered a binary pulsar- two extremely dense and heavy stars in orbit around each other….and this was exactly the type of system that, according to general relativity, should radiate gravitational waves” (LIGO 1).
Astronomers used this chance to observe whether the behavior of the two bodies would align with the theory of relativity. Eight years of observation revealed that the stars were moving closer just as Einstein had predicted in his theory of relativity. It is now over 40 years since the two scientists started correlating the behaviors of two dense stars to the theory of relativity.
The notion of GW was conceived 100 years ago by Einstein but the journey to detect them directly has been long and tedious. The ability to detect GW requires complex science some of which consists of pioneering technology. The waves that were detected on February 11 involved a joint effort of about 1000 physicists in collaboration with LIGO. LIGO consists of two observation locations and identical machines that are located in Livingston, Louisiana and Hanford, Washington.
After rumors persisted for weeks about the discovery of GW by LIGO, the institute finally confirmed this groundbreaking development in February 11 2016. According to the official report, “LIGO researchers sensed a wave that stretched space by one part in 1021, making the entire Earth expand and contract by 1/100,000 of a nanometer, about the width of an atomic nucleus” (Cofield 1).
LIGO detects GW by watching out for incidences where space stretches even though the measurements of these distortions might be minuscule in proportion. For instance, in the latest discovery LIGO’s four kilometers arms only recorded a movement that was equivalent to the width of a single hair. Consequently, the precision that is required in the measurement is important to the wave detection process. The mechanism of GW detection by LIGO involves is as follows:
“Mirrors at the ends of each arm form a long “resonant cavity,” in which laser light of a precise wavelength bounces back and forth, resonating just as sound of a specific pitch rings in an organ pipe. Where the arms meet, the two beams can overlap. If they have traveled different distances along the arms, their waves will wind up out of step and interfere with each other. That will cause some of the light to warble out through an exit called a dark port in synchrony with undulations of the wave.” (LIGO 1).
The length of the two giant arms can enable scientists to detect even the most minute GW, as the stretching of the sections is measurable. Nevertheless, scientists have to factor out other sources of vibrations such as seismic waves, ground movements, and oceanic waves.
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During the latest discovery, computer simulations revealed that the GW was as a result of two massive objects that were about twenty-nine and thirty-six times the size of the sun orbiting each other and finally becoming one object. The objects were only 210 kilometers from each other before merging and this led scientists to conclude that they were black holes. Black holes are constituted solely of massive gravitational energy as occasioned in Einstein’s famous equation E=MC2.
Detection of GW depends on the activity of exotic astral objects such as black holes and neutrons, some of which are still a quagmire to astronomers and physicists. For example, the discovery of the GW was also the first incidence where the existence of black holes was detected. Previously, black holes could only be witnessed by observing the behavior of the objects near them. One scientist notes that the debate over the existence of black holes is now over (Zollman and Brown 325). Data from the detection of GW also revealed that when the two black holes merged they lost a substantial amount of their mass in form of gravitational radiation.
The Future of GW
The most revolutionary aspect of the GW discovery is the fact that astronomers have gained a new portal through which they can ‘observe’ the universe. GW gives observers a way to hear the things about the universe that they cannot see. After the discovery, the LIGO Executive Director was quoted saying: “what’s going to come now is we’re going to hear more things, and no doubt we’ll hear things that we expected to hear … but we will also hear things that we never expected” (Cofield 1). This new age of information points to a great future in astronomy. Onwards, scientists will have new methods of observing previously mysterious astral objects such as neutron stars and black holes.
Another game-changing aspect of the GW discovery is the fact that all detections come with a back-story. For instance, most GW are the result of violent cosmic events that can reveal other important details about the universe. Consequently, GW observatories have the potential to reveal details that are inaccessible through the existing modes of observations such as telescopes. In other cases, light from cosmic events can be blocked from view but GW cannot be hidden. For example, the activities of black holes do not emit any light and this means that GW detectors give the only hope of studying them in future.
The discovery of GW follows a pattern where astronomers are able to venture into new frontiers, as it was the case with telescopes, x-rays, gamma rays, and electromagnetic waves (Abbott 68). Each of these groundbreaking developments has enabled scientists to study new information about the cosmos. Consequently, the discovery of GW and modes of analyzing them is expected to do the same. In future, scientists are hoping o harness the fine details of GW and the theory of relativity. For instance, the graviton, or the element that carries the force of gravity is yet to be applied to everyday science.
The recent discovery of GW is a phenomenon that is 100 years in the making. On the other hand, when Einstein first predicted the existence of GW the basis of their reality appeared so far-fetched thereby creating doubt about the entire theory of relativity. In 2016, the question is no longer whether GW exist, but how they will contribute to the future of science. It is possible that in the coming decades the existence of previously mysterious objects such as neutron stars, supernovas, and black holes will have been demystified.
Aasi, John. “Searches for Continuous Gravitational Waves from Nine Young Supernova Remnants.” The Astrophysical Journal 813.1 (2015): 39. Print.
Abbott, Brian. “Search for Gravitational Waves from Binary Inspirals in S3 and S4 LIGO Data.” Physical Review 77.6 (2008): 62-102. Print.
Cho, Adrian. “Fear and Loathing in the Hunt for Gravitational Waves.” Science 352.6283 (2016): 300-301. Print.
Cofield, Calla. “Gravitational Waves: What their Discovery Means for Science and Humanity.” Space.com. 2016. Web.
LIGO. “Gravitational Waves.” LIGO Caltech. 2016. Web.
Zollman, Dean A., and Duncan Brown. “An Introduction to the Theme Issue.” American Journal of Physics 84.5 (2016): 325-326. Print.