Please note! This essay has been submitted by a student.
The interesting concept of gravitational waves has been known for over 100 years, but it was just recently detected, and it is incredibly important to our lives. Gravitational waves in outer space are invisible ‘ripples,’ or waves caused by very violent and energetic events in the universe. In other words, they are changes in the pull of gravity caused by mass moving around. Any object with mass that moves produces gravitational waves, including humans, cars, and trains. The gravitational waves made by us on Earth are too small to detect. They travel like ripples in a pond, getting smaller as they travel farther away from their source. They are also incredibly fast, travelling at the speed of light, around 186,000 miles per second. They squeeze and stretch anything in their path as they pass by. The most powerful gravitational waves are created during catastrophic events when objects move at very high speeds, like when two black holes orbit each other and merge, or when stars orbit each other or collapse.
Gravitational waves were actually predicted to exist back in 1916. Albert Einstein predicted its existence in his theory of relativity. He showed that large moving objects, like black holes orbiting each other, would disrupt space so that ‘waves’ of distorted space would radiate from the source. Though gravitational waves were predicted to exist, there wasn’t any actual proof of their existence until 1974. Two astronomers working at an observatory in Puerto Rico discovered two extremely dense and heavy stars orbiting each other. This was exactly the type of event that should radiate gravitational waves. Knowing that this discovery could be used to test Einstein’s prediction, astronomers began measuring how the period of the stars’ orbits changed over time. After eight years of observations, they found out that the stars were getting closer to each other at the exact rate predicted by Albert Einstein in the theory of relativity. The changes in the orbit agree with general relativity, so there is no doubt that it is emitting gravitational waves. Unfortunately, these confirmations have always come indirectly or mathematically and not through actual detection.
Gravitational waves are washing over Earth all the time, but our instruments have not been sensitive enough to detect them until recently. In September of 2015, scientists detected gravitational waves for the very first time. They used an instrument called LIGO, also known as the Laser Interferometer Gravitational-Wave Observatory. When a gravitational wave passes by Earth, it squeezes and stretches space. LIGO detects these motions. Each of the two LIGO observatories has two long ‘arms.’ A gravitational wave passing by causes the length of the arms to change slightly. The observatory uses lasers, mirrors, and very sensitive instruments to detect these tiny changes. These first gravitational waves happened 1.3 billion years ago, when two black holes crashed into one another, but, the ripples didn’t make it to Earth until 2015. While the origins of gravitational waves can be extremely violent, by the time the waves reach the Earth they are much smaller and less disruptive. The first detection of gravitational waves was a monumental event in science. Since LIGO’s first detection, we’ve gained unexpected insight into space. Before, almost everything we knew about the universe came from studying waves of light. Now, we have a new way to learn about the universe, and understand it, by studying waves of gravity. With this latest detection, astronomers were able to combine gravitational waves with more traditional ways of seeing the universe. Detecting and analyzing the information carried by gravitational waves will allow us to observe the universe in a completely new way. It will open up a new window of study on the Universe, give us a deeper understanding of these events, and bring in new research in physics, astronomy, and astrophysics. We may even learn more about gravity itself.
In conclusion, the discovery of gravitational waves is one of the greatest human scientific achievements, and it has changed the way we think and live. It’s exciting to imagine what revelations may now be spreading across space towards our tiny planet and its new way of perceiving and understanding the universe.