This geologist made not one but two major contributions to our understanding of how the Earth works. Read about his geologic time scale and his contributions to the theory of continental drift.

Until the late 18th century, most people believed the Earth was about 6,000 years old. Hutton changed this belief by proposing that geologic forces operate at the same rate today as in the past.

The intense heat and pressure of the deep Earth are hard to imagine—and even harder to re-create. Currently, scientists need to work with samples so small they look like a grain of ground pepper.

While the idea that continents have drifted over time dates back to the 16th century, it wasn't until the 20th century that scientists figured out how plate tectonics work.

Each one of the thousands of earthquakes that occur every year offers a brief glimpse of what's happening deep inside the Earth. Lehmann used seismic signals to change our knowledge of the Earth's core.

Traditional healers are among those hurt by logging and development of the rain forest. In Central America, they've joined forces with farmers and scientists to preserve Belize's plant diversity.

By taking biopsy-like samples from centuries-old Siberian pines, scientists have reconstructed a 300-year record of temperature changes for the Arctic and the Northern Hemisphere.

In the past century, how much has life changed in the North Pacific? Explore this question with photographs on display in eight regional museums in the Russian far east.

Working without the aid of a computer, this mathematician went back 6,000 years and calculated how cycles in the Earth's orbit affect the advance and retreat of the polar ice caps.

One is the riskiest number... A more diverse plant population has a better chance of adapting to changes in the environment. Learn how to quantify the biodiversity of any area.