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Q. The planet is known as the ‘blue planet’ is the _ _ _ _ _ _
A. Earth
B. Mars
C. Jupiter
D. Pluto
Ans. Earth
Because of its high water content (about 70%), Earth is also known as the blue planet.
The abundance of water on the surface of the Earth has earned it the moniker “Blue Planet.” We take liquid water for granted here on Earth; after all, our bodies are primarily composed of water. Liquid water, on the other hand, is a scarce resource in our solar system. Although no liquid water has been verified in our solar system, liquid oceans are thought to exist beneath the frozen crusts of Jupiter’s moon Europa and Saturn’s moon Enceladus. There hasn’t been a single drop of water found in interstellar space yet. Liquid water can only exist on a planet with the right mass, chemical composition, and location. Only such worlds could support life as we know it.
The majority of our planet’s surface is covered in liquid water. This water comes in a variety of forms, each with its unique set of characteristics. Rain is essentially pure water (containing only H₂O with trace amounts of elements and other compounds picked up from air dust), but fresh spring water, most lakes and rivers, and most springs contain more dissolved salts (0.02-0.4 per cent, or parts per hundred). Ocean water is substantially saltier, with an average salt concentration of 3.5 per cent (also known as “salinity”). Note that 3.5 percent equals 35 parts per thousand (ppt), the standard measure for reporting salinity and that this figure equals 35,000 parts per million (ppm) – a ppt is 1 gramme of salt dissolved in 1000 grammes of water, or a gramme per kilogramme (g/kg). Some spring and lake waters are saltier than the ocean, and they are referred to as “brines” because they can become salt-saturated. These various forms of water can be found in a variety of places on the planet.
