The Earth and Solar System have been evolving for 4.6 billion years. In this timeline, you can see how the key events fit into such a vast expanse of time. Notice that many of the formative events took place in the first 100 million years.

4,600 million years ago
Solar System's first solid grains—the building blocks of planets — form.

4,600-4,500 million years ago.
Within the first 100 million years, our Earth and Moon, the large asteroids, and the other planets and moons come into being.

4,000-3,800 million years ago
Cataclysmic bombardment of the Moon occurs.

2,000 million years ago
Earth’s atmosphere becomes markedly rich in oxygen as the number of photosynthetic plants increases.

540 million years ago
Life on Earth undergoes massive evolution and diversification.

200 million years ago
Supercontinent Pangaea begins to rift apart, breaking up into today's continents.

65 million years ago
Asteroid impact on Earth leads to extinction of many species, including dinosaurs.

1.8 million years ago
Homo erectus, closest ancestor of modern humans, appears.