We love our nature as they give beauty. Do you know that how the earth has a green colour, because of the nature only. But now the greenary is decreasing from maximum pollution and building so many factories and from that so many people's are dying by the oxygen power so please do not cut trees do not hunt animals and maintain the number of people. Now you will be curious why is there blue part in the earth that is ocean,The ocean formed billions of years ago.

The distance to the center of the Earth is 6,371 kilometers (3,958 mi), the crust is 35 kilometers (21 mi) thick, the mantle is 2855km (1774 mi) thick and the remaining distance extends upto core of the earth. After five years, the Kola well had reached 7km (about 23,000ft). Work continued until the project was abandoned in 1989 because the drill became stuck in rock at a little over 12km (almost 40,000ft or 8 miles) deep. That is the current record for a depth reached by humans.

Over vast periods of time, our primitive ocean formed. Water remained a gas until the Earth cooled below 212 degrees Fahrenheit . At this time, about 3.8 billion years ago, the water condensed into rain which filled the basins that we now know as our world ocean.A further asteroid particle study supported the theory that a large source of earth's water has come from hydrogen atoms carried on particles in the solar wind which combine with oxygen on asteroids and then arrive on earth in space dust.Now you will be thinking that how deep is ocean,the average depth of the ocean is about 3,682 meters (12,080 feet). The deepest part of the ocean is called the Challenger Deep and is located beneath the western Pacific Ocean in the southern end of the Mariana Trench, which runs several hundred kilometers southwest of the U.S. territorial island of Guam.