Earth is estimated to be 4.54 billion years old, +- 50 million years. This estimate is based on the analysis of Earth’s crust, its rocks, and those of the Moon, and several meteorites, using radiometric dating methods. Earth formed around 4.54 billion years ago, approximately one-third the age of the universe, by accretion from the solar nebula.
Human-like forms, or hominids, diverged from other primates somewhere between 2.5 and 4 million years ago. The earliest known hominid species is Sahelanthropus tchadensis, which lived about 7 million years ago. However, the modern human species, Homo sapiens, evolved much later, around 300,000 years ago. Homo sapiens is part of a larger group of human species called Homo, which also includes extinct relatives such as Neanderthals and Denisovans.
