Eon (geology) facts for kids

In geology, an Eon is the largest division of geologic time. Think of Earth's entire 4.5-billion-year history as a giant timeline. Geologists break this timeline into big chunks, and the biggest chunks are called Eons. There are four main Eons:

• Hadean Eon: This is the oldest Eon, starting when Earth first formed. It was a time when the planet was very hot and still forming.
• Archean Eon: During this Eon, the first simple life forms, like bacteria, started to appear in the oceans.
• Proterozoic Eon: This Eon saw the development of more complex single-celled life and the first simple multi-celled organisms.
• Phanerozoic Eon: This is the current Eon we live in, which started about 541 million years ago. It's known for the explosion of complex life, including plants, animals, and eventually humans.

Each Eon represents hundreds of millions or even billions of years!