These gorgeous images were taken by the sophisticated NASA instrument MODIS (MODerate resolution Imaging Spectroradiometer). Land surface data were acquired from June through September of 2001. The clouds were acquired on two separate days--July 29, 2001, for the Northern Hemisphere and November 16, 2001 for the Southern Hemisphere.

Image courtesy NASA
  • On April 22, 1970, the first Earth Day was observed. Twenty million people participated in the inaugural events. Earth Day was founded by Sen. Gaylord Nelson (D-Wisconsin) an environmentalist. The two largest gatherings of the first Earth Day were held in Washington, D.C., and New York City. However, events were hosted all over the nation, at colleges, universities, and schools, and in communities. This first Earth Day was designed to educate participants in the importance of the environment. It was created to advocate for conservation and sustainability. Nelson urged students and fellow environmentalists to raise awareness about ecology with the same passion that displayed by opponents to the Vietnam War.
    Earth Day paved the way for many environmental organizations, and even the Environmental Protection Agency, which was created just eight months later. It also helped to create support for legislative acts such as the Clean Air Act. Today, Earth Day encourages the importance of long-term ecological sustainability. It helps us to be aware of the demand for clean water, air, and land. More than 200 million people in 141 countries celebrate Earth Day every April 22.
  • Term Part of Speech Definition Encyclopedic Entry
    advocate Verb

    to argue in favor of something.

    conservation Noun

    management of a natural resource to prevent exploitation, destruction, or neglect.

    Encyclopedic Entry: conservation
    Earth Day Noun

    April 22, an international holiday to honor the need to protect the environment.

    Encyclopedic Entry: Earth Day
    environmentalist Noun

    person who studies or works to protect the Earth's ecosystems.

    inaugural Adjective


    sustainability Noun

    use of resources in such a manner that they will never be exhausted.

    Encyclopedic Entry: Sustainability