Interesting Questions And Answers| Ignored Truths

If you say 70% then you are partially right. Seven-tenths of earth's surface is covered in water. But taking the Earth's mass into consideration water doesn't even account for fiftieth of one percent.The Earth is big-it weighs about 6 million,billion,billion kg. Half of this is mass is contained in the lower mantle, the massive semi-molten layer that begins 660 km (410 miles) below the crust, the mass of the land is forty times greater than that of the oceans.

A Japanese  experiment reported in Science in 2002 suggests that there may be five times as much as water dissolved in the lower mantle than sloshing around the Earth's surface. Using a pressure of 200,000 kg per cm and temperature of 1600^o C, the researchers created four mineral compounds similar to those found in the lower mantle. They added water and measured how much of it was absorbed.

If the Japanese are right, the proportion of the world that is water will have to be revised upwards - to 0.1 per cent.