In our regular life, we cannot see some things because they are invisible, but they are constantly exposed to us. So check out the things we can’t see with our eyes in this guide below.
Things we cannot see with our eyes
There are many things in the world that are invisible to human eyes. These things are often invisible to us. For example, air is invisible, but we can feel it. Similarly, what we cannot see with our eyes is sound. We can hear sounds like music, voices and animal noises, but we cannot see where the sound is coming from.
Even the stars, planets and galaxies are far away from us, so we cannot see them clearly without the use of telescopes or other scientific instruments. In science, dark matter and dark energy are also invisible substances, although we cannot see them directly.
Black holes
We can see millions of stars twinkling in the sky on a clear night, but not exactly. This is because of the light that each of these celestial bodies emits. However, due to the lack of light, the rest of the celestial bodies in our Milky Way Galaxy, estimated at ten million to one billion, are invisible to our eyes.
On the other hand, black holes absorb light and do not let it through. Because light cannot pass through black holes due to their extreme density. Even with the most advanced tools and technologies available today, it is impossible to detect even a single black hole.
UV/infrared light
We already know that there are seven different colors that make up the sunlight we see. Since light consists of electromagnetic radiation, each of its colors has a specific wavelength. Only wavelengths between 380 nanometers and 700 nanometers are visible to the human eye.
We cannot see any radiation or light from either side of this belt. Not only are ultraviolet and infrared light waves with wavelengths less than 380 nm and greater than 700 nm invisible to humans, they can also be harmful to us if exposed for long periods of time.
Air
We can survive for several days, even without food and water, but we cannot survive more than a few minutes without air. Because the air we breathe is invisible to us. Although we cannot see it, we can feel it, store it, and even transport it. Air is a mixture of gases, primarily composed of nitrogen and oxygen, which are only visible under the constraints of extremely low temperatures and high pressure. The fact that something so important to our existence is still not visible to us.
Radiation
Radiation and waves are the basis of modern communication. The mobile phone is where our day begins and ends. We use radios to hear songs and news, microwaves for cooking and Wi-Fi in our offices to send data around the world. Radio waves have a wavelength of approximately 10 cm, while microwave radiation has a wavelength of 1 cm. This is because the wavelengths of these radiations are beyond our visible range.
Objects that spin
Consider a scenario where you are driving a car and someone is trying to overtake you. As you look out the window, you’ll see that the other car’s wheels are actually spinning backwards, which is called the “wagon wheel” effect, an optical trick that results in this tricky thing.
This effect is created by the spinning motion of the rotating wheel, which gives the impression that the spokes are bending and moving on the opposite side. We experience the same thing when we look at a ceiling fan. Beyond a certain speed, it is impossible to see the wheel spokes or fan blades moving in the correct direction.
Causes of diseases
A report in the journal states that scientists calculate that the average number of human cells is about 30 trillion for a person weighing 70 kg, 1.7 meters tall and between 20 and 30 years old. In contrast, there are approximately 39 trillion bacteria inside our body. No matter how big a bacterium is, we still can’t see it because anything smaller than 0.1 mm in length is not visible to the human eye. In such cases we would need a microscope.
Excessive exposure to these substances, especially radiation and microbes, is extremely harmful to human health. Although we are constantly exposed to these things in our everyday life, they are still invisible to us.
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Categories: General
Source: HIS Education