Formation of the Earth

Answer

The earth is generally believed to be four to five billion years old. This is the broad accepted range used in the chapter.

Answer

Modern scientific methods to know the age of the earth have been used for about two centuries. These methods include tidal force, sedimentation, erosion, salinity of the ocean, and radioactivity.

Answer

By the tidal friction first method, the age of the earth is calculated as 4000 million years, or 4 billion years. The idea is linked to the moon’s changing tidal friction as it moved away from the ear…

Answer

The moon is moving away from the earth at the rate of 13 cm per year. Scientific study of tides and rotation of the earth gave this value.

Answer

The moon is currently 3,84,000 km away from the earth. At a rate of 13 cm per year, it would take 2.95 billion years to move this distance. On this basis, the age of the earth is determined at 4 billi…

Answer

The age of the earth = The thickness of sediment / The annual rate of deposit in of the sediment. This method uses the thickness of sedimentary layers and their yearly deposition rate.

Answer

The age of the sedimentary rocks has been calculated as 4 billion years on this basis. Some scientists also believe erosion could not have started for at least one billion years after the earth's birt…

Answer

The rate of sedimentation per year is not the same every year and differs from place to place. Many interruptions also occur in the sedimentary sequence. These changes make the method less exact.