A sound below 20 cycles a second is called infrasound. Infrasound is a type of low-frequency sound that is below the threshold of human hearing. Despite being inaudible to most people, infrasound can still have an impact on our bodies and surroundings.

Infrasound is often produced by natural phenomena such as earthquakes, volcanic eruptions, and severe weather events. It can also be generated by man-made sources like airplanes, machinery, and explosions. Infrasound waves are so low in frequency that they can travel long distances and penetrate through obstacles like buildings and mountains.

While we may not be able to hear infrasound, our bodies can still detect it. Studies have shown that exposure to infrasound can lead to a variety of physical and psychological effects, including nausea, dizziness, fatigue, and even feelings of fear or unease. This is because infrasound can affect our vestibular system, which is responsible for our sense of balance and spatial orientation.

Despite its potential negative effects, infrasound can also be used in beneficial ways. For example, some studies suggest that exposure to infrasound may have therapeutic effects, such as reducing stress and anxiety. Infrasound is also used in various technologies, such as seismic monitoring, military applications, and even music production.

Overall, infrasound is an interesting and powerful phenomenon that plays a significant role in our environment and daily lives. While we may not be able to hear it, its effects are still felt by our bodies and surroundings. Whether it's the rumble of an earthquake or the hum of a passing airplane, infrasound is a constant presence that shapes our world in ways we may not always be aware of.

Next time you feel a strange sensation or unease without a clear cause, remember that it could be the subtle influence of infrasound at work.

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