The Earth formed about 4.54 to 4.6 billion years ago. It originated from a cloud of gas and dust called the solar nebula that collapsed under gravity, leading to the formation of the Sun and surrounding planets. Earth started as a protoplanet and grew through collisions and accretion of planetesimals. It experienced differentiation into core and crust and a giant impact with a Mars-sized body likely led to the formation of the Moon. This formative period set the stage for Earth's early geological history and the eventual development of its atmosphere and oceans.