Light: Visible & Invisible

When we look at the world around us, we see a dazzling array of colors, shapes and textures. But what we see is only a tiny fraction of the electromagnetic spectrum, the range of wavelengths that includes visible light, as well as radio waves, microwaves, infrared, ultraviolet, X-rays and gamma rays. Most of the electromagnetic spectrum is invisible to our eyes, and some of it can even pass through solid objects.

Invisible light is the wavelengths in the electromagnetic spectrum too short or too long to be detected by the human eye.

Visible light is the part of the electromagnetic spectrum that our eyes can detect. It consists of wavelengths from about 380 nanometers (nm) to about 740 nm. The percentage of the electromagnetic spectrum that the human eye can see is about 0.0035 percent. The colors that we perceive depend on the wavelength and intensity of the light. For example, red light has a longer wavelength and lower frequency than blue light, which has a shorter wavelength and higher frequency.

But visible light is only a small portion of the electromagnetic spectrum. Below it, there are radio waves, which have wavelengths from about 1 millimeter (mm) to more than 100 kilometers (km). Radio waves are used for communication, such as radio, television and cell phones. They can also be used for radar, navigation and astronomy.

Above visible light, there are infrared waves, which have wavelengths from about 740 nm to 1 mm. Infrared waves are emitted by warm objects, such as humans, animals and stars. They can be detected by special cameras and sensors, and are used for thermal imaging, night vision and remote sensing.

Beyond infrared waves, there are ultraviolet waves, which have wavelengths from about 10 nm to 380 nm. Ultraviolet waves are produced by the sun and other hot objects, such as stars and black holes. They can cause sunburns and skin cancer, but they can also kill bacteria and help produce vitamin D. They are used for sterilization, fluorescence and astronomy.

Above ultraviolet waves, there are X-rays, which have wavelengths from about 0.01 nm to 10 nm. X-rays are generated by high-energy processes, such as nuclear reactions and collisions of electrons with atoms. They can penetrate many materials, such as bones and metals. They are used for medical imaging, security scanning and crystallography.

Finally, there are gamma rays, which have wavelengths shorter than 0.01 nm. Gamma rays are the most energetic and dangerous form of electromagnetic radiation. They are produced by nuclear explosions, radioactive decay and cosmic events. They can damage living cells and cause mutations and cancer. They are used for nuclear medicine, radiation therapy and astronomy.

As you can see, most of the light in the universe is invisible to our eyes. The human eye can only see a tiny fraction of the electromagnetic spectrum, which is the range of all types of radiation. This fraction is called the visible light spectrum, and it consists of wavelengths from about 380 to 700 nanometers. The percentage of the electromagnetic spectrum that the human eye can see is about 0.0035 percent.

What would happen if we see all light?

Seeing all the light at once would be overwhelming and confusing. We would not be able to distinguish between different sources and types of light, and everything would appear as a bright and chaotic mess. We would lose the ability to perceive shapes, colors, depth, and contrast. We would also be exposed to harmful radiation that could damage our eyes and skin.

Therefore, seeing all the light is not a desirable or realistic scenario. Our vision is fashioned in such a way that the specific range of light is visible that is relevant and useful for our survival and well-being. Seeing more or less than that would impair our perception and cognition, rather than enhance it.

Points to Ponder:

There are many types of light which human can see with the help of specialized equipment, however is it possible to have other kind of light that is still not make known to humankind?

There is natural gear and sensors that prevents man from seeing much of light which can be greatly hazardous for life. Are these sensors specially catered for or it just get developed?