Keep reading to learn more about Earth's different layers, its atmosphere, and what makes the "blue planet" unique. Earth is made out of different layers, and those layers get hotter and more ...

Instead, it's documented in layers and layers of rock ... Geology Introduction: The Changing Planet Earth has been significantly altered over its 4.6-billion-year history by climate swings ...

Geologists have calculated the age of Earth at 4.6 billion years ... Even the Greeks and Romans realized that layers of sediment in rock signified old age. But it wasn't until the late 1700s ...