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).
Auroras occur in the next layer, which is known as the ionosphere, or thermosphere, and finally the. exosphere gradually thins and merges with empty space. The troposphere is the layer of Earthâs atmosphere that meteorologists. watch most closely because itâs where weather happens. Of all the layers.