Things We Cannot See With Our Eyes But Exists
by T Santhosh
Updated Mar 28, 2024
Things We Cannot See With Our Eyes
There are a lot of 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 using telescopes or other scientific instruments. In science, dark matter and dark energy are also invisible substances, even though we cannot see them directly.
Black Holes
We can see a million stars glittering in the sky on a clear night, but not accurately. This is due to the light that each of these celestial bodies emits. However, due to the lack of light, other celestial bodies in our Milky Way galaxy, which are estimated at ten million to a billion, are invisible to our sight.
On the other hand, black holes absorb light and don’t let it pass through. Since light cannot get through the black holes because of their extreme density. Even with the most advanced tools and technologies available today, it is impossible to detect even one black hole.
UV/Infrared light
We already know that there are seven distinct colors that make up the sunlight that we see. Since light is made up of electromagnetic radiation, each of its colors has a particular wavelength. Only wavelengths between 380 nanometers and 700 nanometers are visible to the human eye.
We are unable to see any radiation or light on either side of this band. Not only are ultraviolet and infrared light waves with wavelengths less than 380 nm and greater than 700 nm invisible to humans, but they can also be harmful to us if they are exposed for a long period of time.
Air
We can survive for a few days, even without food and water, but we cannot survive for more than a few minutes without air. Since the air we breathe is invisible to us. Though we cannot see it, we can feel it, store it, and even transport it. The air is a mixture of gases, primarily composed of nitrogen and oxygen, that are only visible under the constraints of extremely cold temperatures and high pressures. The fact that something so essential to our existence is still not yet visible to us.
Radiation
Radiation and waves are the foundations of modern communication. A cell 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 globe. Radio waves have a wavelength of roughly 10 cm, while microwave radiation has a wavelength of 1 cm. This is because the wavelengths of these radiations are beyond our visible range.
Spinning objects
Consider the scenario where you are driving a car and someone tries to overtake you. As you look through the window, you'll see that the other car's wheels are actually turning in reverse, which is termed the "wagon-wheel" effect, an optical illusion that results in this tricky thing.
This effect is produced by the spinning motion of the rotating wheel, which gives the impression that the spokes are bending and moving on the opposite side. We also experience the same thing when we watch a ceiling fan. Beyond a certain speed, it is impossible to see the wheel spokes or the fan blades moving in the correct direction.
Pathogens
A report in the magazine states that scientists calculate the average human cell count to be around 30 trillion for a person weighing 70 kg, 1.7 meters tall, and between the ages of 20 and 30. In contrast, there are roughly 39 trillion bacteria inside our body. No matter how big the bacterium is, we are still unable to see it since anything smaller than 0.1 mm in length is not visible to human eyes. We would need the microscope in such cases.
Overexposure to these substances, particularly radiation and microbes, is extremely harmful to human health. Even though we are constantly exposed to these things in our daily lives, they are still invisible to us.
