Mesosphere: The mesosphere of a terrestrial planet is the third member of the atmosphere. On Earth, the mesosphere starts atop the stratosphere at approximately 50 kilometers above mean sea level and terminates roughly 85 kilometers above mean sea level. The mesosphere is where most meteors burn to determination. Like the stratosphere, the air in the mesosphere is thin. However, the oxygen levels in the mesosphere are too low to sustain human life. And much like the troposphere, temperatures increase with altitude within the mesosphere. The next member of the atmosphere above the mesosphere is the thermosphere.