ionosphere
[ahy-on-uh-sfeer]
- the region of the earth's atmosphere between the stratosphere and the exosphere, consisting of several ionized layers and extending from about 50 to 250 miles (80 to 400 km) above the surface of the earth.
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Origin of ionosphere
Dictionary.com Unabridged
Based on the Random House Unabridged Dictionary, © Random House, Inc. 2018
Examples from the Web for ionosphere
Historical Examples
Then we were able to modify that to heave sand and to let it tap the ionosphere.
Sand DoomWilliam Fitzgerald Jenkins
They struck the Earth's ionosphere, and their numbers diminished.
Out Like a LightGordon Randall Garrett
The ionosphere of Eisberg was much deeper and, although the intensity was less, the duration was much longer.
Unwise ChildGordon Randall Garrett
Without the landing grid and the power it took from the ionosphere, they could not receive supplies from the rest of the universe.
Sand DoomWilliam Fitzgerald Jenkins
It was not the intensity of the ionosphere that cracked the drive of the Brainchild; it was the duration.
Unwise ChildGordon Randall Garrett
ionosphere
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Collins English Dictionary - Complete & Unabridged 2012 Digital Edition
© William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins
Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012
Word Origin and History for ionosphere
Online Etymology Dictionary, © 2010 Douglas Harper
ionosphere
[ī-ŏn′ə-sfîr′]
- A region of the Earth's upper atmosphere, extending from a height of 70 km (43 mi) to 400 km (248 mi) and containing atoms that have been ionized by radiation from the Sun. The ionosphere lies mostly in the lower thermosphere and is subdivided into three regions, the D region (70 km to 90 km; 43 to 56 mi), the E region (90 km to 150 km; 56 to 93 mi), and the F region (150 km to 400 km; 93 to 248 mi). The concentration of ionized atoms is lowest in the D region, intermediate in the E region, and highest in the F region. The ionosphere is useful for radio transmission because radio waves, which normally propagate in straight lines, are reflected off the ionized gas particles, thereby being transmitted long distances across the Earth's curved surface. See more at D region E region F region.
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The American Heritage® Science Dictionary
Copyright © 2011. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.
ionosphere
[(eye-on-uh-sfeer)]
A region of the atmosphere that begins at an altitude of about thirty miles.
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Note
In this region, free particles carrying an electrical charge, atoms ionized (see ionization) by radiation from the sun, reflect radio waves. “Bouncing” radio waves off the ionosphere makes communication possible over long distances of the surface of the Earth.
The New Dictionary of Cultural Literacy, Third Edition
Copyright © 2005 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.