from The American Heritage® Dictionary of the English Language, 4th Edition

  • n. A region of the earth's atmosphere where ionization caused by incoming solar radiation affects the transmission of radio waves. It extends from a height of 70 kilometers (43 miles) to 400 kilometers (250 miles) above the surface.

from Wiktionary, Creative Commons Attribution/Share-Alike License

  • n. The part of the Earth's atmosphere beginning at an altitude of about 50 kilometers (31 miles) and extending outward 500 kilometers (310 miles) or more.
  • n. The similar region of the atmosphere of another planet.

from the GNU version of the Collaborative International Dictionary of English

  • n. the outer region of the earth's atmosphere, beyond which is the exosphere; it contains a high concentration of free electrons and ions, and extends from about 50 miles to about 250 miles above the earth's surface, but the height shows daily and seasonal variation, and the composition of the particles in the ionosphere is also affected by events such as solar flares.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

  • n. the outer region of the Earth's atmosphere; contains a high concentration of free electrons


from Wiktionary, Creative Commons Attribution/Share-Alike License

iono- + -sphere


  • Nobel Prizeman himself, who gave me the warmest encouragement and help when I began to work on the ionosphere, is not alive today to let me hear his own words of approval.

    Edward V. Appleton - Banquet Speech

  • We have a diurnal pattern of a distribution of earthquakes controlled by a current in the ionosphere, which is controlled by the activity on the sun.

    SETI Institute: Life at the SETI Institute: Friedemann Freund - The Future of Forecasting Earthquakes

  • CFCs are also safe, inert and nonpoisonous-until they reach the ionosphere, that is.

    Ecoology Breakthrough: A Cfc-Less Fridge

  • The ionosphere is a duo-layered crust of particles several miles thick holding the atmosphere in place.

    Global Warming Creating Colder Winter Weather? 'Tis True

  • The ELF (extremely low frequency) resonator formed by the cavity between the Earth and the lower E-region of the ionosphere is a nature! resource, that will actually permit the terrestrial distribution of electrical power across a continent, without the necessity of an interconnecting land-line grid of high tension transmission lines.

    Chapter 6

  • This vast region, beginning at a height of approximately fifty kilometres and extending outwards for several radii of the Earth, is now known as the ionosphere; its exploration by rockets, satellites and radio waves has been a continuing process for more than two centuries.

    The Fountains of Paradise

  • The ionosphere is the wayward child of the sun; even now, its behaviour is not always predictable.

    The Fountains of Paradise

  • No, son, the ionosphere is the ceiling until we think up something better than rockets.

    The Past Through Tomorrow

  • "The ionosphere is a region of the upper atmosphere where there are a significant number of charged particles," Mr. Pedersen said.

    Signs of the Times

  • The green fireball might have provided an electrical connection between the ground and the ionized layer of atmosphere known as the ionosphere, providing the energy needed for ball lightning.

    Yahoo! News: Business - Opinion


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