SOLAR SYSTEM

Detailed explanation-1: -Formation. When the solar system settled into its current layout about 4.5 billion years ago, Earth formed when gravity pulled swirling gas and dust in to become the third planet from the Sun. Like its fellow terrestrial planets, Earth has a central core, a rocky mantle, and a solid crust.

Detailed explanation-2: -Precambrian time covers the vast bulk of the Earth’s history, starting with the planet’s creation about 4.5 billion years ago and ending with the emergence of complex, multicelled life-forms almost four billion years later.

Detailed explanation-3: -Once upon a time, about 4.5 billion years ago, the Earth was an unformed doughnut of molten rock called a synestia-and the moon was hidden in the filling. That’s one possible explanation for the moon’s formation, anyway.

Detailed explanation-4: -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.

Detailed explanation-5: -And researchers studying those grains say that 4.4 billion years ago, Earth was a barren, mountainless place, and almost everything was under water. Only a handful of islands poked above the surface. Scientists at the Australian National University are behind this study, led by researcher Dr. Antony Burnham.