AP BIOLOGY

Detailed explanation-1: -History. According to evidence from radiometric dating and other sources, Earth formed about 4.54 billion years ago.

Detailed explanation-2: -What was first thing in Earth 4.5 billion years ago? Over 4.5 billion years ago, our solar system formed from a giant molecular cloud that collapsed under its own tremendous gravity. The hot stew of hydrogen and helium gave birth to our sun and flung out a wide disc of gas and particles in the surrounding space.

Detailed explanation-3: -Earth is estimated to be 4.54 billion years old, plus or minus about 50 million years. Scientists have scoured the Earth searching for the oldest rocks to radiometrically date.

Detailed explanation-4: -By dating the rocks in Earth’s ever-changing crust, as well as the rocks in Earth’s neighbors, such as the moon and visiting meteorites, scientists have calculated that Earth is 4.54 billion years old, with an error range of 50 million years.

Detailed explanation-5: -Earth formed around 4.54 billion years ago, approximately one-third the age of the universe, by accretion from the solar nebula. Volcanic outgassing probably created the primordial atmosphere and then the ocean, but the early atmosphere contained almost no oxygen.