Meteorites

Many of the meteorites found on Earth are estimated to be around 4.6 billion years old. Meteorites are believed to be small rock bodies which failed to become planets, but remained when the solar system was formed. When these small bodies collide, come together, and grow to become planets, the resultant energy accumulates within the planets in the form of heat. The earth, newly formed due to such collisions, became so hot as to melt all its rocks and lose its original properties. The oldest rocks on earth are believed to have originated from when the planet cooled and solidified. Therefore, as with meteorites, the age of the earth is estimated to be around 4.6 billion years old.