Introduction

Gravitational waves, the ripples in the fabric of spacetime caused by certain cosmic events, were first detected in 2015 by LIGO (Laser Interferometer Gravitational-Wave Observatory). Since then, the field of gravitational wave research has thrived, revealing new insights into the universe. However, has anyone felt the effect of the primordial gravitational waves that were discovered just two weeks ago? The answer is a resounding no. Here, we explore why gravitational waves are so subtle and why we cannot perceive them in the same way we feel the ground shake during an earthquake.

The Nature of Gravitational Waves

Gravitational waves are not like seismic waves. Unlike the ground vibrations that we can feel during an earthquake, gravitational waves are incredibly faint and subtle. Imagine a very faint wave in a lake. The effect on your boat depends on the size of this wave. If we liken the Earth to a boat on the lake, we can make some essential inferences: the lake is very calm in most areas, and it is also unexpectedly vast, with its edges far beyond our vision.

A Wave from the Edge of the Lake

Picture this: on the far side of this immense lake, two whirlpools representing black holes collide, producing a wave. As this wave travels across the lake, it weakens with distance. Furthermore, the expanding lake makes the wave fainter over time. By the time this wave reaches our boat, it is so faint that it is undetectable on the surface. We can only notice its presence through specialized instruments that can measure the infinitesimal changes in the surface, which symbolize spacetime and the curvature of spacetime as a result of the gravitational wave.

Comparing the Unfelt Waves to the Felt X-rays

The effect of these gravity waves is about a million times less than the feeling of a grain of salt on your shoulder. Just like you couldn't feel the difference between the grain of salt before it fell off and after it fell off, the same is true for gravitational waves. The human nervous system is not built to perceive these extremely subtle phenomena. In fact, humans can only respond to a very narrow range of stimuli that are essential for immediate individual action and survival.

The Limits of Human Perception

Our perception is limited to a very small range of phenomena. We can see, hear, and feel things that are relevant to our immediate needs and survival. Things that occur extremely fast or slowly, like cosmic time and geological changes, are beyond our direct experience. Even changes that affect our long-term existence, such as aging, are mostly out of our conscious awareness unless we use instruments or engage in special calculations.

Human Evolution and Perception

Human perception is a result of our evolutionary history. We have not evolved to sense very brief events or changes over long periods. This requires considerable effort and specialization. For instance, the invention of the compass, night goggles, X-ray machines, sonar, and radar all exemplify how humans have developed instruments to extend our sensory capabilities. As individuals, we may be capable of sensing these things, but it takes a great deal of effort and specialized training.

Conclusion

In the realm of gravitational waves, we are akin to a boat on a vast, calm lake, barely registering the faintest tremor from the far side. The primordial waves that were detected a few weeks ago are so subtle that they cannot be felt or detected by human senses alone. However, the study of these waves continues to expand our understanding of the universe, pushing the boundaries of what is possible with our instruments and our minds.