Optical illusions are all about light, how it reaches our eyes and how our brain interprets them. A lot of physics is involved in understanding them.
You can think of many optical illusions made by man. But there are quite a number of them found in nature too. Some are interesting and some are unbelievable. Some are easy to be explained and some are hard to believe even after the explanation. You can call them pranks on us by nature ;)
Scroll down to see the various optical phenomena occurring in nature:
1. Twinkle Twinkle Little Star...
Remember "Twinkle Twinkle little star"? Probably the first rhyme you learnt after you started learning. Did you know that rhyme was based on an optical phenomenon? The fact is stars DO NOT twinkle.
Stars appear to twinkle because of turbulence in the atmosphere of the Earth. What happens is the light emitted by a star gets refracted in different directions which causes the brightness and the position of the image to keep changing slightly. Hence, the effect of twinkling is created.The images of the planet do not appear to twinkle because the size of a planet on the sky is big enough to eliminate the turbulent effects of the atmosphere, presenting a relatively stable image to the eye, whereas the stars are as good as a point of light due to the great distance they are at.
The nursery rhyme would have existed if its creator wrote from the moon. The stars won't twinkle if seen from any other celestial body because of the absence of atmosphere.
2. Beautiful Red Sunsets
Its easy to imagine a scenery of sunset. Isn't it? The basic color flashing before the eyes is red when it comes to imagining a scene of sunset. The sun does not change its color from yellow in the day time to red/orange at the time of sunset.
The reason of setting sum to appear red is that as the sun moves to a lower position, the light from it passes through more of atmosphere present near the horizon. The denser air molecules let only the red components of the white sunlight to travel, scattering away the rest of the colored components.A similar reason stands for the sky being blue. The air molecules scatter the blue components the most from all the seven colors with which sunlight is formed.
3. The Dark Colored Band In The Air
You must have noticed a dark blue or almost blackish band that stretches all over the horizon during the time of sunset. That is the shadow of our very own Earth, on its atmosphere. That is why it appears in opposite direction of the sunset i.e in the eastern sky. Similar scenario can be seen during sun rise, but in the eastern sky.
The Earth's shadow is very long and has a curve which is obviously because of the round shape of Earth. Lunar Eclipse is also the result of shadow of Earth falling on Moon. It happens when the all the three from Sun, Earth and Moon come in a straight line.
4. Water Water Everywhere...
This is one of the finest optical phenomenas occurring in nature. Imagine yourself on a hot, sunny day, wandering in a desert, without any water. The one thing you would wish for more than anything is water. That is what exactly you are likely to get an illusion of.
Light has different speed to travel in hot air and cool air. Mirage occurs when ground is hot and the air is cool. The air just above the ground is warmed due ti the heat from the ground. As the light passes from the cool air to the warm air, it bends. Our brain assumes the light to be in a straight line and that it is coming out from something on ground. Thus, creating the image of water.Mirage is very commonly found in deserts because of the heat. But they are likely to be seen anywhere if there is a difference in temperatures of air.
5. Fata Morgana
If mirage is strange, Fata Morgana is stranger. It is a superior form of a mirage. It distorts the image of the object or objects, to an extent that the objects become unrecognizable. the first picture is a Fata Morgana of a boat.
A Fata Morgana can be seen on land or at sea, in polar regions or in deserts. This kind of mirage can involve almost any kind of distant object, including boats, islands, and the coastline. A Fata Morgana is often rapidly changing due to changes in the temperature. The mirage comprises several inverted and erect images that are stacked on top of one another.
Fata Morgana is the Italian name for Morgan le Fay, the half-sister of King Arthur in Arthurian legend. Reputedly a sorceress who could change shape at will. She was said to live below the sea in a crystal palace that could also rise above the surface. The Fata Morgana effect was so named for the superstitious belief among sailors that she created illusory visions to lure men into a false port and to their death. The term first entered English usage in 1818.
Did you know the science behind such phenomenon? Do you know about more such fascinating things around you? Share your experiences with us in the comments below.Stay tuned to E-junkie for more such interesting stuff.
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