One of the most exciting things about science is that it allows for the continual refinement and adaption of hypotheses, even after many years. Ideas that were completely theoretical can become concrete, and each generation is influenced by, and builds upon, the next.
It was just about a century ago that Albert Einstein proposed the existence of gravitational waves, and now practical experimentation has finally caught up to his theoretical analysis. Recently, researchers at the Laser Interferometer Gravitational-wave Observatory announced they had detected gravitational waves. This discovery confirms the predictions of Einstein’s theory of general relativity.
How were gravitational waves detected?
There are now research facilities dedicated to observing these waves and their effect on the natural world. Laser Interferometer Gravitational-wave Observatory, or LIGO, consists of two installations, one in Washington state and another in Louisiana, that work together to provide observations and insight into this fascinating natural phenomenon.
What are gravitational waves?
When a charge accelerates, it produces an electromagnetic wave. Similarly, when a mass accelerates, it produces a sort of wave of its own: gravitational. In most cases, these waves are undetectable, even by modern scientific standards. However, if the object is large enough — like a massive star — the resulting wave can be observed. The source of this disturbance may be in the Milky Way, or another relatively close galaxy.
When the wave passes by an observer, space-time is strained at a magnitude that is inversely proportional to the distance from the source.
How are gravitational waves measured?
There are two primary hurdles to measuring these waves: amplitude and distance. They have very small amplitudes, which make their effect miniscule, and they, like most everything in space, occur very far away. Only recently has the technology existed to investigate the waves, after the development of specialized types of Michelson interferometers. These machines combine powerful lasers and photodetectors. The lasers are split in two along an L-shape — one beam along each arm of the shape — which are then reflected back to the junction.
“Gravitational waves are capable of affecting light.“
Under normal circumstances, the beams bounce back and cancel each other out. However, gravitational waves are capable of affecting light, and as such can disrupt the pattern of one of the beams, which results in some light reaching the end of the junction. The photodetector picks up this activity, and the presence of a wave is suggested.
LIGO has three of these interferometers: two in Washington and one in Louisiana. To better analyze the results received, the observatory partners with similar organizations in Germany and Italy. Over time, the sensitivity of the instruments has gotten increasingly better, allowing more precise results and more usable data.
What is the future of gravitational waves?
The ability to measure this activity could have a profound influence on the future of astrophysics. Gravitational waves can pass through virtually anything without being dispersed, and do not need matter to be generated in the first place. This combination means that they are capable of carrying previously impossible-to-obtain information, including data about rare astrological phenomena. In fact, the confirmation of the existence of these waves is an important clue in piecing together the origins of the universe itself and can help scientists further understand space.
How can you integrate new discoveries into your lessons?
Exciting new scientific discoveries that make headlines are great opportunities to integrate current events into your lessons. In this case, it’s a chance to cover the foundational concepts in physics, astrophysics, and quantum mechanics that made the discovery of gravitational waves possible.
All of this foundational content is available in McGraw-Hill Education’s AccessScience—the award-winning STEM teaching and learning resource developed specifically for students and non-specialists. For instance, AccessScience provides in-depth articles written by expert scientists—complete with illustrations, photos, and links to citable literature—on the essential topics related to the discovery gravitational waves.Tags: STEM learning, stem science, gravitational waves, theory of general relativity, physics, astrophysics, quantum mechanics