Look up: exosphere

1. Exosphere
   The outermost layer of the Earth's atmosphere.
   Found on http://www.bbc.co.uk/weather/weatherwise
   
   
2. exosphere
   [n] - the outermost atmospheric layer
   Found on http://www.webdictionary.co.uk/definitio
   
   
3. Exosphere
   The outermost part of the Earth's atmosphere. It is an ill-defined, highly rareified zone which starts at a height of about 700km (435 miles) and extends into the vacuum of space.
   Found on http://www.delscope.demon.co.uk/astronom
   
   
4. Exosphere
   This region is considered the very outer limits of the earth's atmosphere. Its lower boundary is often called the critical level of escape, where gas atoms are so widely spaced that they rarely collide with one another and have individual orbits. It is roughly 640000 metres above the surface of the Earth.
   Found on http://www.diracdelta.co.uk/science/sour
   
   
5. Exosphere
   The layer of the atmosphere lying above 400 km altitude. More Information.
   Found on http://www.atm.ch.cam.ac.uk/tour/glossar
   
   
6. exosphere
   region of the atmosphere upwards from about 500 km from which it is thought that the lighter gases may escape to space Category: The cosmos
   Found on http://www.mijnwoordenboek.nl/definition
   
   
7. exosphere
   noun the outermost atmospheric layer
   Found on http://wordnetweb.princeton.edu/perl/web
   
   
8. exosphere
   outermost region of a planet`s atmosphere, where molecular densities are low and the probability of collisions between molecules is very small. The ... [1 related articles]
   Found on http://www.britannica.com/eb/a-z/e/59
   
   
9. Exosphere
   The outermost zone in the Earth's atmosphere. This layer has an altitude greater than 480 kilometers and is primarily composed of hydrogen and helium gas.
   Found on http://www.physicalgeography.net/physgeo
   
   
10. EXOSPHERE
    This region is considered the very outer limits of the earth's atmosphere. Its lower boundary is often called the critical level of escape, where gas atoms are so widely spaced that they rarely collide with one another and have individual orbits. It is estimated to be some 400 plus miles (640 kilometers) above the surface. Related term: ionosphere
    Found on http://www.weather.com/glossary/e.html
    
    
11. exosphere
    the outer part of the Earth's atmosphere located above the thermosphere, in which the collision frequency is sufficiently low that the probability that certain particles will escape towards free space is relatively high when the vertical velocity of these particles is sufficiently high
    Found on http://www.electropedia.org/iev/iev.nsf/
    
    
12. exosphere
    exosphere: see atmosphere.
    Found on http://www.infoplease.com/ce6/sci/A09132
    
    
13. exosphere
    Uppermost layer of the atmosphere. It is an ill-defined zone above the thermosphere, beginning at about 700 km/435 mi and fading off into the vacuum of space. The gases are extremely thin, with hydrogen as the main constituent
    Found on http://www.talktalk.co.uk/reference/ency
    
    
14. Exosphere
    The `exosphere` is the uppermost layer of Earth`s atmosphere. In the exosphere, an upward travelling molecule moving fast enough to attain escape velocity can escape to space with a low chance of collisions; if it is moving below escape velocity it will be prevented from escaping from the celestial ...
    Found on http://en.wikipedia.org/wiki/Exosphere