What is Gravitational Waves?

Find out how the movement of matter influences the curvature of space-time and leads to the creation of gravitational waves.

Mar 25, 2023 - 15:13
Jul 15, 2023 - 22:34
What is Gravitational Waves?
Image source: Nasa , Gravitational Waves.

In 1915, Einstein introduced his general theory of relativity, which seeks to describe the relationship between space-time and matter. Since then, numerous experiments have been conducted to test the validity of this theory, and the results have consistently astounded people with their accuracy and depth. At first, many people found it hard to believe that the world and the universe could be so different from what they had always assumed. However, as experimental evidence continued to pile up, people gradually came to accept that their previous understanding of the world was incomplete. They began to see that the world was more complex and intriguing than they had ever imagined.

Despite the unquestionable accuracy of the general theory of relativity, scientists have yet to detect gravitational waves, an important prediction of the theory. This has caused frustration among scientists who view general relativity as a fundamental pillar of modern physics. Despite this, they remain steadfast in their belief that gravitational waves are real and have devoted significant efforts over several generations to detecting them (which will be discussed in more detail in later chapters). So what exactly are these elusive gravitational waves?

To describe it in the simplest terms, gravitational waves can be described as "ripples in space-time". The concept of ripples occurring in both time and space may seem mysterious, so let me explain it more slowly. Many students may not have a strong grasp of general relativity, but there is no need to panic. In just a few minutes, you can learn the basics of this theory and use it to understand many of the concepts presented in this article.

To understand the concept of general relativity, one only needs to know two simple sentences. The first sentence is likely familiar:

  • Space-time is four-dimensional, comprised of three dimensions of space and one dimension of time. Space-time unifies space and time into a single entity.

    For example: You are presently occupying a specific point in time and space as you read this sentence.

    The second sentence is even more remarkable! It will give anyone an idea of what the general theory of relativity is discussing!

  • Space-time tells matter how to move; matter tells space-time how to bend or curve.

    Well, it's very simple. The general theory of relativity explains that space-time governs the movement of matter, while matter causes space-time to curve. This implies that how matter, such as objects with mass or energy (which has mass), moves in space-time depends on the nature of the space-time it is in. Conversely, space-time will be curved as long as matter is present within it. The extent and type of curvature are determined by the amount and distribution of matter within it.

Look, we don't need to worry about complicated mathematical formulas to understand the theory of relativity. We can still understand the fundamental concept of this theory. With this understanding, we can delve into the concept of gravitational waves more easily.

Look at a picture first:

The two black objects in the image are black holes, which are incredibly massive celestial bodies. Due to their huge mass, they cause space-time to bend according to the principle "matter tells space-time how to bend." Imagine a still lake. When an object is placed on its surface, it causes a curved dent in the water. This is similar to the effect of black holes on space-time nearby. When only one object is present, the water remains calm. However, if two objects move around each other like the black holes in the picture, the disturbance created is enormous, causing ripples in space-time.

Friends, let's consider this analogy - if the surface of water is space-time, then the ripples on it are gravitational waves. Gravitational waves are not just some abstract concept, but rather they are the actual distortions or fluctuations in space-time! Now, doesn't this make it easier to understand the concept? I believe that the more profound a theory is, the more accessible and understandable it can be made.

Careful learners may have realized that the movement of matter is the foundation for gravitational waves. The larger the mass of matter and the more intense its movement, the greater the disturbance to space-time, resulting in stronger gravitational waves.

Black holes are massive celestial objects, and as per "matter tells space-time how to bend," their mass causes significant curvature of space-time in their vicinity. In the image, two black holes are locked in a dance, so it's no surprise that time and space are experiencing upheaval around them.

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Sakib I am Sajedul Islam Sakib from Bangladesh. Currently I am a student at software engineer but also I like reading and learning new things, especially about Blogging and Education.