This document provides a brief description of the major currents and general circulation patterns of the world's oceans. Links to animations showing satellite imagery of ocean-surface topography and temperature are included. Links to references are embedded in the text. Full description.

This document discusses the history of mass extinctions throughout geologic time, their role in the evolutionary process, and a mathematical model that demonstrates how the evolutionary process might interact with environmental stresses to produce a distribution of extinctions similar to that seen in the fossil record. Full description.

This article discusses the United States' increasing vulnerability to natural disasters because of population and infrastructure concentrations in disaster-prone areas. Topics include the high cost of earthquakes, hurricanes, and tornadoes, a discussion of the frequency and severity of these events, changes in population and wealth as measured by revenue, and ways to decrease hazard vulnerability. Full description.

This collection of visualizations was made from Landsat imagery. Many of these visualizations are designed to show changes in our environment through time. Subjects include glacial retreat, urban growth, landforms and coastlines, floods, fires, deforestation, volcanism, and others. Full description.

This collection of images, movies, and animations from NASA's Solar and Heliospheric Observatory (SOHO) features a large selection of images of the sun and of solar phenomena. Although most of the imagery is of the sun, a few images of comets and planets as they transit the solar disk are available. Full description.

Visitors to this site can read and view satellite imagery about the most recent La Nina event, which produced less-than-normal snowfalls in Western North America. A TOPEX/Poseidon image of the Pacific ocean illustrates the warmer water and higher-than-normal sea surface height in the Western Pacific which are characteristic of a La Nina event. A discussion of the uncertainties of long-range climate ... Full description.

Users can learn about the GEOTAIL spacecraft and its mission to study the Earth's magnetotail. Materials presented include an overview of the project, a diagram of the spacecraft, and a description of the instrument packages carried aboard the satellite. Full description.

Students can learn about the conditions necessary for hurricanes to form and sustain themselves. The discussion is accompanied by remote imagery and an animation showing how wind shear can retard the development of a hurricane. Links to more detailed information are embedded in the text. Full description.

This document provides the user with an introduction to the structure and physical properties of the Sun. A brief discussion of hydrogen fusion is included, along with a table that lists some numerical information about our star. Links to a glossary are embedded in the text, and links to related sites are also provided. Full description.

This archive of ocean-color imagery produced by SeaWiFS and Aqua-MODIS contains images from 2002 to the present. The images are viewable in a variety of formats: chlorphyll concentration, sea surface temperature, aerosol index, smoke index, and many others. Yearly, seasonal, monthly, weekly, or daily images are available. Full description.