Question

Why does the earth appear blue from space?
A) About 71% of the earth’s surface is covered with water which gives blue colour to earth
B) Earth is covered with blue air
C) Earth is covered with blue coloured mountains and rocks
D) All of the above

Answer 1

Hint:A combination of all the shades of the rainbow is the white light of the sun. Isaac Newton, who used a prism to distinguish the various colors and thereby form a spectrum, proved this. Light colours are described by their varying wavelengths.

Complete answer:
First we should know about Earth to answer this question. Earth is the Sun’s third planet and the only known astronomical object harbouring life. The Earth evolved about 4.5 billion years ago, as per radiometric dating calculations as well as other evidence. The gravity of the Earth engages with other space objects, notably the Sun and the Moon, as that is the only natural satellite of the Earth.
Now, let us find the solution from the options-
- The earth is largely (71 percent of the surface of the earth) covered by water. Water blocks the radiation of white light (sunlight). In reality, the sunlight looks white from a mixture of lights of many different colors. As illumination enters the water, the water consumes white light and reflects just blue light, lights of all colors. The earth from space, thus, looks blue. If all colors are removed by the water and only yellow is reflected, only yellow will appear.
- When molecules in the air emit blue light from the sun rather than they emit red light, a bright cloudless daytime sky is blue. We see red and orange shades as we look at the sun at sunset when the blue light has been spread out and out of the line of sight. Thus, option B is not the correct option.
- As they comprise particles greater than the wavelengths of light, which spread all wavelengths evenly, clouds and dust haze look white. But there may be other pollutants in the air which are much smaller also. The blue haze of certain mountainous regions is popular. Thus option C is not the correct option.

So, the correct answer is option (A) About 71% of the earth’s surface is covered with water which gives blue colour to earth.

Note: Any other blue coloration in existence is important for the Tyndall effect: like blue eyes, the opalescence of certain gemstones, and the colour on the wing of the blue jay. Based on the size of the dispersing particles, the colors may differ.