Albert Einstein’s Theory of Relativity revolutionized the discipline of physics, allowing for a deeper understanding of the relationship between space and time as well as the universe as a whole. But like most groundbreaking scientific discoveries, this theory was initially met with skepticism and disillusionment. What Einstein's Theory of Relativity lacked was the ability to directly detect gravitational waves due to significant noise complications at low frequencies where the antennae are in operation... until now.
On Feb. 11, 2016, the Laser Interferometer Gravitational Wave Observatory (LIGO) in affiliation with the National Science Foundation announced that for the first time in history, a team of their scientists had succeeded in directly detecting gravitational waves. This is the first evidence to support Einstein's prediction of the existence of gravitational waves. This groundbreaking achievement comes a century after Einstein proposed his Theory of General Relativity in 1915.
What is Einstein's Theory of General Relativity?
Einstein’s Theory of General Relativity is essentially an explanation of the structure, expansion and fate of the universe. In order to understand this theory, one must first understand space-time, which is the four dimensional combination of space and time. While we can move through three dimensions, our motion through a fourth dimension, time, is only in one direction. Gravity can cause two space probes moving around Earth to meet. This theory states that space-time can be curved (or distorted). General Relativity suggests that movements of massive objects such as black holes can produce gravitational waves, just as movements of a charged particle can produce light waves. Over the course of billions of years, two black holes orbiting around one another slowly approach, only moving faster in the last minutes before they collide. Once the two black holes collide, they merge to form a massive black hole. In doing so, part of the combined black holes’ mass is converted to energy, as displayed in Einstein’s formula E=mc2.
How did scientists manage to detect gravitational waves?
According to the LIGO Press Release, "The discovery was made possible by the enhanced capabilities of Advanced LIGO, a
major upgrade that increases the sensitivity of the instruments compared to the first
generation LIGO detectors, enabling a large increase in the volume of the universe
probed—and the discovery of gravitational waves during its first observation run."
Dr. Thorne, one of the main physicists involved in this project, explained that the black holes observed by LIGO "created a storm in which the flow of time speeded, then slowed, then speeded. A storm with space bending this way, then that.” Two massive black holes collided and merged, causing the production of gravitational waves that LIGO detected in September of 2015. Astrophysicists estimated that this took place more than a billion years ago!
The sound that scientists heard of these black holes colliding lasted only one-fifth of a second. The sound has been described as a 'thud' or a 'chirp.'
What does this mean for the future of physics?
This recent announcement thrilled the international scientific community, particularly those studying and working in the disciplines of physics, astrophysics and astronomy.
According to Dr. Thorne, “with this discovery, we humans are embarking on a marvelous new quest: the quest to explore the warped side of the universe—objects and phenomena that are made from warped space-time. Colliding black holes and gravitational waves are our first beautiful examples.”
The newfound ability to detect gravitational waves can pave the way for future discoveries in physics and astronomy. As France Cordóva, the director of the National Science Foundation (NSF), eloquently said, "Einstein would be beaming, wouldn't he?" He certainly would be.
