The region of the [[atmosphere]] above an altitude of 285 miles.<ref>Wile, Dr. Jay L. ''Exploring Creation With Physical Science''. Apologia Educational Ministries, Inc. 1999, 2000</ref>
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The '''exosphere is the region of the [[atmosphere]] above an altitude of 285 [[mile]]s.<ref>Wile, Dr. Jay L. ''Exploring Creation With Physical Science''. Apologia Educational Ministries, Inc. 1999, 2000</ref> The exosphere is the upper most layer of the [[earth]]'s [[atmosphere]]; the only layer where atmospheric gases can escape into [[outer space]].<ref>http://www.weather.gov/glossary/index.php?letter=e</ref>