Without Light, There Won’t Be Any Sight
- Nov 21, 2016
- Sudipto Das
The visual ability of humans, as well as other animals, is a result of the complicated interaction of eyes, brains and most importantly, light. Once light reaches the eyes, certain signals are sent to the brain. The brain deciphers such information and thereby, you’ll be able to detect the location, appearance, and movement of the objects that are in sight. Without light, there won’t be any sight.
How do we actually see objects?
To see a specific object, light from that object has to enter the eyes. We can see various luminous objects like lightning, stars, the sun, light bulbs, etc. because they emit light. The light enters our eyes, and we can see the objects effortlessly.
Regarding non-luminous objects, we have to depend on the light emitted from luminous objects. Say, for example, the paper of a book. The paper doesn’t emit light but we can see the paper because light is reflected off the paper and enters into the eye.
So you see that if you switch off the lights in a room and cover up all the windows such that no light enters into the room, you will notice that no object in the room is visible. The room actually has objects that were visible a moment ago. There is a pair of eyes present in the room as well for detection (yours). There’s also the presence of a brain (yours) to decipher any information. But since there’s the absence of light, you would not be able to see any object.
The appearance of black is just a sign of the absence of light.
The difference between luminous objects and illuminated objects
Objects can be placed in 2 categories:
- Luminous objects,
- Illuminated objects.
Luminous objects, as we said above are the ones that emit light. Example- stars, the sun, light bulb, any light sources.
Illuminated objects are those objects capable of reflecting the light into the eyes. Example- the moon, the paper of a book observed under optimal light, etc.
Without luminous objects, we will not be able to see non-luminous objects
The sun emits light to illuminate objects on the earth. The sun is a luminous object for which you can actually detect objects on the earth.
During the evening, the earth comes to a position where the light from the sun does not reach your half of the earth. Therefore, everything appears to be black. Artificial sources of light become very important at that point of time because you won’t be able to visualize objects without light.
None of us emit light in the visible zone of the electromagnetic spectrum. We aren’t luminous objects. In simpler words, we are more or less similar to that of the moon. We make our existence known to others by reflecting the light to the eyes of people looking our way. It’s only due to reflection for which we see most objects in the physical world.
With that, we’ll bring this article to an end. Hope you had a good read.
Sudipto writes technical and educational content periodically for wizert.com and backs it up with extensive research and relevant examples. He's an avid reader and a tech enthusiast at the same time with a little bit of “Arsenal Football Club” thrown in as well. He's got a B.Tech in Electronics and Instrumentation.
Follow him on twitter @SudiptoDas1993
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