This search tool provides descriptions and availability information for geologic maps of the 50 States, the District of Columbia, and Puerto Rico. These geologic maps are published by a variety of organizations, including State geologic agencies, the U.S. Geological Survey (USGS), universities, and private companies. Title, date, scale, publisher, series (where applicable), and basic ordering information ... Full description.

This short biography of Copernicus describes his major contribution to science, the idea that the planets, including Earth, moved in orbits around the Sun. Links to additional information on related topics are embedded in the text. Full description.

This site presents information about the Advanced Composition Explorer (ACE) spacecraft and its mission, science goals, history, and background. The mission summary includes a brief description of the energetic particles from the sun and from interstellar and galactic sources that are the objectives of the ACE mission. Links to additional information are also supplied. Full description.

This site displays a brief animation of a supernova explosion and presents an explanation of the types and causes of supernovae. Links to a glossary are embedded in the text. Full description.

This document provides a brief introduction to supernova explosions. Topics include types of supernovae, causes of the explosions, and what happens to the material in a star after the explosion. Links to a glossary are embedded in the text. Full description.

This document discusses the loss of rainforest in South and Central America. Topics include the rate of disappearance and the primary causes. Links to conservation- and rainforest-related charitable sites are included. Full description.

Biosphere reserves are sites recognized under UNESCO's Man and the Biosphere Programme which innovate and demonstrate approaches to conservation and sustainable development. They are internationally recognized, nominated by national governments and remain under sovereign jurisdiction of the states where they are located. Biosphere reserves serve in some ways as 'living laboratories' for testing out ... Full description.

This guide provides information about caves in the United States which are open to the public. The directory is arranged by state and provides locations, operating hours, and telephone numbers for all caves in the U. S. which are developed for public access. Other materials include tips for visitors, a tutorial on cave photography, and a link to the "Virtual Cave," which includes maps and photos of ... Full description.

This text explains how glaciers scour and grind the Earth's surface, and about the sorts of deposits they leave behind. Emphasis is on glaciation in the mountains and valleys of Vermont. Links to related topics are included. Full description.

This online pamphlet discusses the concept of geologic time. Topics include the relative and radiometric time scales, the use of index fossils in making age determinations, and current thinking on the age of the Earth. Full description.