Earth Formation, Age and Composition
Earth Formation
The Earth is the third planet on the Solar system which is inhabited by living things. The Earth was formed about 4.6 billion years ago, and it’s formation composition consists of a mixture of dust and gas. The Earth took shape and formed by constant collisions between dust particles, asteroids, and other smaller outer space planets.
Earth’s Age
The Earth’s age is estimated to be around 4.54 billion years. The scientific technique used to determine the age of the Earth is called Radiometric dating. In these technique, the ratios of various radioactive isotopes present in samples are measured to calculate its age. The Radiometric dating has three (3) major types used to determine the age of his samples it includes uranium-lead, radiocarbon and lead-lead dating.
Using the radiometric dating technique, meteorites which usually consists of bits of rock that have broken off from asteroids can be used to estimate the age of the Earth. Meteorites are better preserved than rocks on Earth, which disintegrate and breakdown through various chemical phases and with the movement of plate tectonics.
Earth’s Composition
The Earth’s composition consists of the Core, mantle, and crust.
Crust
The Crust is the Earth’s outer surface, which is 1% earth by mass. The crust is thin, has a brittle outer shell which is made up of rocks. The crust also has two main distinctive types which are Oceanic crust and Continental crust.
Mantle
The mantle consist of the highest percentage by mass of the Earth’s size. The mantle contains about 68% of Earth by mass, and the mantle is very hot and contains mainly solid rocks.
Core
The core contains of mostly iron metal and it contains the second percentage by mass after the mantle. The core consists of about 31% of the Earth.
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