Atmosphere of Earth However, polar stratospheric or nacreous clouds are occasionally seen in the lower part of this layer of the atmosphere where the air is coldest. The stratosphere is the highest layer that can be accessed by jet-powered aircraft. The troposphere is the lowest layer of Earth's atmosphere. It extends from Earth's surface to an average height of about , although this altitude varies from about at the geographic poles to at the Equator, with some variation due to weather. The troposphere is bounded above by the tropopause, a boundary marked in most places by a temperature inversion (i.e. a layer of
Live Earth concert, Washington, D.C. Gore speak and Brooks play from what event organizers called a "JumboTron" outside the immediate viewing area. Due to last minute organizing, there were no working audio speakers that could project sound to the JumboTron viewers. Live Earth concert, Washington, D.C. The Live Earth concert in Washington, D.C., officially known as "Mother Earth", was held on the National Mall in Washington, D.C., United States and was sponsored by and held on the premises/venue of the Smithsonian's National Museum of the American Indian. It was only hours before the Washington D.C. concert was scheduled to begin that organizers were able to