The Earth

The Earth is over 4.54 billion years old (4,540,000,000)and still has many things we don't know about.  One thing we are still researching is Earth's layers because we can't go down beneath the Earth's surface also known as the crust.  On this website you will learn about Earth's layers:  The crust, the moho, the mantle, the lithosphere, the asthenosphere, the mesosphere, the inner core, and outer core.