The Navajo are the second largest tribe in the U.S. and they have the largest reservation stretching across Colorado, Utah, New Mexico and Arizona with over 25,000 square miles. They were also among the largest group of Indians to migrate to Los Angeles in the 1950s and 60s.
The ionosphere is a shell of electrons and electrically charged atoms and molecules that surrounds the Earth, stretching from a height of about 50 km (31 mi) to more than 1,000 km (620 mi).
The Ionosphere. Exosphere. The Exosphere is the outermost layer of the atmosphere. It extends from the thermopause-the transition boundary which separates the exosphere from the thermosphere below-to 6,200 miles (10,000 km) above the earth.tratosphere. The Stratosphere extends from the tropopause up to 31 miles above the Earth's surface. This layer holds 19 percent of the atmosphere's gases but very little water vapor. Temperature increases with height as radiation is increasingly absorbed by oxygen molecules leading to the formation of Ozone.