可见光只占电磁波谱的一小部分。我们的眼睛对一系列的波长很敏感，但对伽玛

Only a small portion of the visible electromagnetic spectrum. Our eyes are sensitive to a range of wavelengths, but gamma, x-rays, infrared and ultraviolet light is not sensitive. Light travels almost unimaginable speed. C is the velocity of light 3 × 108 m / s, the speed of sound is 330 m / s. The speed of light is faster than sound a million times! In the real world, the speed of light is considered to be the limit. Photons reach the Earth's surface from the sun takes 8 minutes. C is a constant substantially constant universe. No one could tell us why it has such a value. If C is another value, especially when it is a very small value (such as the order of the speed of sound), the communication speed will slow down, we need to spend a lot of hours in order to receive information from other parts of the globe. Air travel unsafe, because we do not know what will happen in front.

Visible light accounts for only a small part of the electromagnetic spectrum. Our eyes are sensitive to a range of wavelengths, but not gamma, x-ray, infrared and ultraviolet. Light travels at an almost unimaginable speed. The speed of light C is 3 x 108 m/s and the sound speed is 330 m/s. Light is a million times faster than sound! In the real world, the speed of light is considered the limit. It takes 8 minutes for photons to reach earth from the surface of the sun. Constant C is the basic constant of the universe. No one can tell us why it has such value. If C is another value, especially if it is a very small value (such as the order of sound velocity), communication slows down, and it takes many hours for us to receive information from other parts of the planet. It's not safe to travel by air because we don't know what's going to happen ahead.

Visible light only accounts for a small part of the electromagnetic spectrum. Our eyes are sensitive to a range of wavelengths, but not gamma, X-ray, infrared and ultraviolet. Light travels at an almost unimaginable speed. The speed of light C is 3 × 108 M / s and the speed of sound is 330 M / s. Light is a million times faster than sound! In the real world, the speed of light is considered the limit. It takes eight minutes for photons to reach the earth from the surface of the sun. Constant C is the fundamental constant of the universe. No one can tell us why it has such value. If C is another value, especially when it is a very small value (such as the order of sound speed), the communication speed will slow down, and it will take us many hours to receive information from other parts of the earth. It's not safe to travel by air because we don't know what will happen in front of us.<br>